DETAILED ACTION
A summary of this action:
Claims 1-22 have been presented for examination.
This action is non-Final.
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Claim Rejections - 35 USC § 101
35 U.S.C. 101 reads as follows:
Whoever invents or discovers any new and useful process, machine, manufacture, or composition of matter, or any new and useful improvement thereof, may obtain a patent therefor, subject to the conditions and requirements of this title.
Claims 1-22 are rejected under 35 U.S.C. 101 because the claimed invention is directed to an abstract idea of a mental process or mathematical concept without significantly more.
Step 1: Claims 1-12 and 21-22 are directed to a method, which is a process and is a statutory category invention. Claims 13-19 are directed to a system, which is a system and is a statutory invention. Therefore, claims 1-22 are directed to patent eligible categories of invention.
Claim 1
Step 2A, Prong 1: Independent claim 13, as drafted, are a process that, under its broadest reasonable interpretation, cover performance of the limitation in the mind but for the recitation of generic computer components. That is, other than reciting “plurality of sensors,” “computing device,” “processor,” and “computer-readable storage,” nothing in the claim element precludes the step from practically being performed in the mind.
Independent claims 1 recites defining a plurality of candidate stimulation treatments comprising injection of an acidic fluid, which is an abstract idea and covers mental processes of assessing the stimulated fluid production from a well in a formation, as described in [6] of the specification, because the claims are derived from Mental Processes based on concepts performed in the human mind or with the aid of pencil and paper.
Independent claim 1 recites based on the measurements, simulating fracture propagation in the formation, induced by pressurized fluid injection, the simulating comprising defining grid cells representing a fracture, which is an abstract idea and covers mental processes of assessing the stimulated fluid production from a well in a formation, as described in [6] of the specification, because the claims are derived from Mental Processes based on concepts performed in the human mind or with the aid of pencil and paper.
Independent claim 1 recites simulating transport of an injected acidic fluid through the formation, wherein the simulating transport comprises tracking movement of units of the acidic fluid between ones of the grid cells, which is an abstract idea and covers mental processes of assessing the stimulated fluid production from a well in a formation, as described in [6] of the specification, because the claims are derived from Mental Processes based on concepts performed in the human mind or with the aid of pencil and paper.
Independent claim 1 recites simulating etching of rock in the fracture to obtain a model of an etched fracture comprising a plurality of rock pillars representing non-uniform etching in the grid cells, which is an abstract idea and covers mental processes of assessing the stimulated fluid production from a well in a formation, as described in [6] of the specification, because the claims are derived from Mental Processes based on concepts performed in the human mind or with the aid of pencil and paper.
Independent claim 1 recites simulating compaction of rock in the formation based on an etched fracture size for each one of the grid cells, to obtain a compacted fracture size associated with each one of the grid cells, which is an abstract idea and covers mental processes of assessing the stimulated fluid production from a well in a formation, as described in [6] of the specification, because the claims are derived from Mental Processes based on concepts performed in the human mind or with the aid of pencil and paper.
Independent claims 1 and 22 similarly recite calculating a predicted fluid conductivity associated with the candidate stimulation treatment, based on the simulating, which is an abstract idea and covers mental processes of assessing the stimulated fluid production from a well in a formation, as described in [6] of the specification, because the claims are derived from a Mathematical Concept based on mathematical relationships, formulas, equations, or calculations.
Independent claims 1 and 22 similarly recite defining a final stimulation treatment based on one of the candidate stimulation treatments and the predicted fluid conductivity, which is an abstract idea and covers mental processes of assessing the stimulated fluid production from a well in a formation, as described in [6] of the specification, because the claims are derived from Mental Processes based on concepts performed in the human mind or with the aid of pencil and paper.
Independent claim 13 recites a measuring characteristics of the formation, which is an abstract idea and covers mental processes of assessing the stimulated fluid production from a well in a formation, as described in [7] of the specification, because the claims are derived from Mental Processes based on concepts performed in the human mind or with the aid of pencil and paper.
Independent claim 13 recites simulating a plurality of candidate stimulation treatments comprising injection of an acidic fluid, which is an abstract idea and covers mental processes of assessing the stimulated fluid production from a well in a formation, as described in [7] of the specification, because the claims are derived from Mental Processes based on concepts performed in the human mind or with the aid of pencil and paper.
Independent claim 13 recites a fracture propagation model for simulating fracture propagation induced by pressurized fluid injection in the formation, by defining grid cells representing a fracture, which is an abstract idea and covers mental processes of assessing the stimulated fluid production from a well in a formation, as described in [7] of the specification, because the claims are derived from Mental Processes based on concepts performed in the human mind or with the aid of pencil and paper.
Independent claim 13 recites a transport model for simulating transport of an injected acidic fluid through the formation by tracking movement of units of the acidic fluid between ones of the grid cells, which is an abstract idea and covers mental processes of assessing the stimulated fluid production from a well in a formation, as described in [7] of the specification, because the claims are derived from Mental Processes based on concepts performed in the human mind or with the aid of pencil and paper.
Independent claim 22 recites defining a plurality of candidate stimulation treatments comprising injection of a slurry comprising acidic fluid and proppant, which is an abstract idea and covers mental processes of assessing the stimulated fluid production from a well in a formation, as described in [8] of the specification, because the claims are derived from Mental Processes based on concepts performed in the human mind or with the aid of pencil and paper.
Independent claim 22 recites based on the measurements, simulating fracture propagation and fluid- proppant slurry transport in the formation, using a particle-in-cell method, which is an abstract idea and covers mental processes of assessing the stimulated fluid production from a well in a formation, as described in [8] of the specification, because the claims are derived from Mental Processes based on concepts performed in the human mind or with the aid of pencil and paper.
Independent claim 22 recites simulating etching of rock in the fracture to obtain a model of an etched fracture comprising a plurality of rock pillars representing non-uniform etching in the grid cells, which is an abstract idea and covers mental processes of assessing the stimulated fluid production from a well in a formation, as described in [8] of the specification, because the claims are derived from Mental Processes based on concepts performed in the human mind or with the aid of pencil and paper.
Independent claim 22 recites simulating compaction of rock in the formation based on an etched fracture size for each one of the grid cells, to obtain a compacted fracture size associated with each one of the grid cells, which is an abstract idea and covers mental processes of assessing the stimulated fluid production from a well in a formation, as described in [8] of the specification, because the claims are derived from Mental Processes based on concepts performed in the human mind or with the aid of pencil and paper.
Thus, the claims recite the abstract idea of a mental process performed in the human mind, or with the aid of pencil and paper.
Dependent claims 2-12 and 14-22 further narrow the abstract ideas, identified in the independent claims. See analysis below.
Step 2A, Prong 2: The judicial exception is not integrated into a practical application. Independent claim 13 recites the additional limitation “plurality of sensors,” “computing device,” “processor,” and “computer-readable storage,” this limitation does not integrate the judicial exception into a practical application because it is nothing more than generally linking the use of the judicial exception to a particular technological environment. See MPEP 2106.05(h). Alternatively, this additional element merely uses a computer device as a tool to perform the abstract idea. (MPEP 2106.05(f)).
The additional recited claims 1 and 13 similarly recite obtaining measurements of formation characteristics, are mere instructions to implement an abstract idea using a computer in its ordinary capacity, or merely uses the computer as a tool to perform the identified abstract idea. See MPEP (2106.05(f)) use of a computer or other machinery in its ordinary capacity for economic or other tasks (e.g., to receive, store, or transmit data) or simply adding a general purpose computer or computer components after the fact to an abstract idea (e.g., a mental process) does not integrate a judicial exception into a practical application. (MPEP 2106.05(f)(2)).
The additional recited claims 1 recites injecting the acidic fluid into the formation according to the final stimulation treatment, are mere instructions to implement an abstract idea using a computer in its ordinary capacity, or merely uses the computer as a tool to perform the identified abstract idea. See MPEP (2106.05(f)) use of a computer or other machinery in its ordinary capacity for economic or other tasks (e.g., to receive, store, or transmit data) or simply adding a general purpose computer or computer components after the fact to an abstract idea (e.g., a mental process) does not integrate a judicial exception into a practical application. (MPEP 2106.05(f)(2)).
The additional recited claims 13 recites injecting the acidic fluid with proppant into the formation according to the final stimulation treatment, are mere instructions to implement an abstract idea using a computer in its ordinary capacity, or merely uses the computer as a tool to perform the identified abstract idea. See MPEP (2106.05(f)) use of a computer or other machinery in its ordinary capacity for economic or other tasks (e.g., to receive, store, or transmit data) or simply adding a general purpose computer or computer components after the fact to an abstract idea (e.g., a mental process) does not integrate a judicial exception into a practical application. (MPEP 2106.05(f)(2)).
Dependent claims 2-12, and 14-22 further narrow the abstract ideas, identified in the independent claims, and do not introduce further additional elements for consideration beyond those addressed above. The additional elements have been considered both individually and as an ordered combination in to determine whether they integrate the exception into a practical application. Therefore, the dependent claims do not integrate the claimed invention into a practical application.
Step 2B:
The claims do not amount to significantly more. The judicial exception does not amount to significantly more. Independent claim 13 recites the additional limitation “plurality of sensors,” “computing device,” “processor,” and “computer-readable storage,” this limitation does not amount to significantly more because it is nothing more than generally linking the use of the judicial exception to a particular technological environment. See MPEP 2106.05(h). Alternatively, this additional element merely uses a computer device as a tool to perform the abstract idea. (MPEP 2106.05(f)).
The additional recited claims 1 and 13 similarly recite obtaining measurements of formation characteristics, are mere instructions to implement an abstract idea using a computer in its ordinary capacity, or merely uses the computer as a tool to perform the identified abstract idea. See MPEP (2106.05(f)) use of a computer or other machinery in its ordinary capacity for economic or other tasks (e.g., to receive, store, or transmit data) or simply adding a general purpose computer or computer components after the fact to an abstract idea (e.g., a mental process) does not amount to significantly more. (MPEP 2106.05(f)(2)).
The additional recited claims 1 recites injecting the acidic fluid into the formation according to the final stimulation treatment, are mere instructions to implement an abstract idea using a computer in its ordinary capacity, or merely uses the computer as a tool to perform the identified abstract idea. See MPEP (2106.05(f)) use of a computer or other machinery in its ordinary capacity for economic or other tasks (e.g., to receive, store, or transmit data) or simply adding a general purpose computer or computer components after the fact to an abstract idea (e.g., a mental process) does not amount to significantly more. (MPEP 2106.05(f)(2)).
The additional recited claims 13 recites injecting the acidic fluid with proppant into the formation according to the final stimulation treatment, are mere instructions to implement an abstract idea using a computer in its ordinary capacity, or merely uses the computer as a tool to perform the identified abstract idea. See MPEP (2106.05(f)) use of a computer or other machinery in its ordinary capacity for economic or other tasks (e.g., to receive, store, or transmit data) or simply adding a general purpose computer or computer components after the fact to an abstract idea (e.g., a mental process) does not amount to significantly more. (MPEP 2106.05(f)(2)).
Dependent claims 2-12, and 14-22 further narrow the abstract ideas, identified in the independent claims, and do not introduce further additional elements for consideration beyond those addressed above. The additional elements have been considered both individually and as an ordered combination in to determine whether they amount to significantly more. Therefore, the dependent claims do not amount to significantly more.
Therefore, the claims as a whole does not include additional elements that are sufficient to amount to significantly more than the judicial exception because the additional elements, when considered alone or in combination, do not amount to significantly more than the judicial exception.
As stated in Section I.B. of the December 16, 2014 101 Examination Guidelines, “[t]o be patent-eligible, a claim that is directed to a judicial exception must include additional features to ensure that the claim describes a process or product that applies the exception in a meaningful way, such that it is more than a drafting effort designed to monopolize the exception.”
The dependent claims include the same abstract ideas recited as recited in the independent claims, and merely incorporate additional details that narrow the abstract ideas and fail to add significantly more to the claims.
Dependent claims 2 and 14 similarly recite “wherein each candidate stimulation treatment comprises a plurality of stages, each having a defined duration, pumping rate, acid type and concentration and proppant type and concentration,” which further narrows the abstract idea identified in the independent claim, which is directed to a “Mental Process.”
Dependent claim 3 recites “wherein the simulating fracture propagation is based on a candidate stimulation treatment, formation properties, and the pressure of injected acidic fluid,” which further narrows the abstract idea identified in the independent claim, which is directed to a “Mental Process.”
Dependent claim 4 recites “wherein the simulating fracture propagation comprises calculating a fracture size for each of the grid cells,” which further narrows the abstract idea identified in the independent claim, which is directed to a “Mental Process.”
Dependent claim 5 recites “wherein the simulating transport of an injected acidic fluid comprises using a particle-in-cell method with the grid cells,” which further narrows the abstract idea identified in the independent claim, which is directed to a “Mental Process.”
Dependent claim 6 recites “for each of the candidate stimulation treatments, simulating transport of a proppant through the fracture using a particle-in- cell method,” which further narrows the abstract idea identified in the independent claim, which is directed to a “Mental Process.”
Dependent claim 7 recites “for each of the candidate stimulation treatments, simulating compaction of rock in the formation around the proppant,” which further narrows the abstract idea identified in the independent claim, which is directed to a “Mental Process.”
Dependent claims 8 and 17 similarly recite “wherein the simulating compaction of rock comprises calculating compression of rock pillars at each one of a plurality of the grid cells,” which further narrows the abstract idea identified in the independent claim, which is directed to a “Mental Process.”
Dependent claims 9 and 18 similarly recite “for each of the candidate stimulation treatments, simulating the consumption of acid by etching of rock,” which further narrows the abstract idea identified in the independent claim, which is directed to a “Mental Process.”
Dependent claim 10 recites “wherein the simulating transport comprises maintaining data records corresponding to units of fluid,” which further narrows the abstract idea identified in the independent claim, which is directed to a “Mental Process.”
Dependent claims 11 and 21 similarly recite “wherein the simulating transport comprises tracking positions of the units of fluid at ones of the grid cells in a plurality of time steps,” which further narrows the abstract idea identified in the independent claim, which is directed to a “Mental Process.”
Dependent claim 12 recites “for each of the candidate stimulation treatments, tracking a consumed portion of acid in ones of the data records corresponding to units of fluid,” which further narrows the abstract idea identified in the independent claim, which is directed to a “Mental Process.”
Dependent claim 15 recites “wherein the simulating fracture propagation comprises defining a formation model based on measurements from the plurality of sensors,” which further narrows the abstract idea identified in the independent claim, which is directed to a “Mental Process.”
Dependent claim 16 recites “wherein the rock bending model includes instructions for simulating bending of rock around proppant,” which further narrows the abstract idea identified in the independent claim, which is directed to a “Mental Process.”
Dependent claim 17 recites “wherein the rock bending model includes instructions for simulating bending of rock around proppant,” which further narrows the abstract idea identified in the independent claim, which is directed to a “Mental Process.”
Dependent claim 19 recites “wherein the simulating transport comprises a particle-in-cell method,” which further narrows the abstract idea identified in the independent claim, which is directed to a “Mental Process.”
Dependent claim 20 recites “wherein the simulating consumption of etching comprises maintaining a data records corresponding to units the acidic fluid, the data records including a proportion of spent acid,” which further narrows the abstract idea identified in the independent claim, which is directed to a “Mental Process.”
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
Claims 1-22 are rejected under are rejected under 35 U.S.C. 103 as being unpatentable over WANG (US 20140251601 A1), herein WANG, MORRIS, (US 20150060058 A1), herein MORRIS, in view of ECONOMIDES (Reservoir Stimulation), herein ECONOMIDES, in view of BULEKBAY, (US 20180334614 A1), herein BULEKBAY, in view of WU (INTEGRATED 3D ACID FRACTURING MODEL), herein, WU, and in view of MOU (Modeling Acid Transport and Non-Uniform Etching), herein MOU.
Claim 1
Claim 1 is rejected because WANG teaches method of acid stimulation of fluid production from a well in a formation WANG ([Abstract] “receiving parameter information for the stimulation operation, the stimulation operation including injecting an acid stimulation fluid into an earth formation along a selected length of a borehole from a tubular disposed in the borehole.”)
WANG also teaches obtaining measurements of formation characteristics WANG ([0003] “Temperature and fluid flow measurements of wellbores in earth formations may be utilized to monitor stimulation processes.”)
WANG also teaches injecting the acidic fluid into the formation according to the final stimulation treatment WANG ([0029] “FIG. 3 is a diagram of an example of fluid flow of acid during an exemplary stimulation. In this example, acid (included in stimulation fluid) is injected from the surface though a conduit such as the tubular 18. The acid flows through an interface (e.g., injection device 24) such as a sliding sleeve valve interface into an annular region of the borehole, i.e., an annulus 46. In this example, the acid is injected into the annulus at the downhole end of an isolated zone near a packer 42. As shown in this example, the acid flows into the formation 16, but also produces a counterflow along the annulus.”)
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WANG does not explicitly teach defining a plurality of candidate stimulation treatments comprising injection of an acidic fluid.
However, MORRIS teaches simulating compaction of rock in the formation based on an etched fracture size for each one of the grid cells, to obtain a compacted fracture size associated with each one of the grid cells MORRIS ([Column 24 | Lines 9-16] “The development of an accurate and efficient numerical 10 model for predicting the deformation and conductivity of either natural or artificially propped fractures is provided. This is achieved by leveraging two internal representations of the pillars/channels within the fracture as: 1) a fine grid for flow simulation to avoid spurious creation or destruction of channels, and 2) a simplified cylindrical pillars to efficiently predict the mechanical changes in aperture.”)
However, MORRIS teaches calculating a predicted fluid conductivity associated with the candidate stimulation treatment, based on the simulating MORRIS ([Column 4 | Lines 28-37] “Another approach approximates detailed asperities with a more coarse collection of cylinders for the mechanical calculation. With both mechanical models, the deformed state is then converted into a pore network model which the conductivity of the fracture during flow-back and subsequent production. This alternative approach may be faster than the first approach and may have reduced accuracy. In some cases, the approaches may be compared for validation and/or to detect issues, such as water injection and multiple fluid interactions.”)
It would have been obvious to one of ordinary skill in the art, before the effective filing date, to combine the teachings of MORRIS with WANG, as the references relates to hydrocarbon production using well stimulation techniques. MORRIS would modify WANG wherein calculating a predicted fluid conductivity associated with the candidate stimulation treatment, based on the simulating. The benefits of doing so may be injected into the wellbore in a manner that provides the desired fractures. (MORRIS [0006]).
The combination of WANG and MORRIS does not explicitly teach defining a final stimulation treatment based on one of the candidate stimulation or simulating transport of an injected acidic fluid through the formation, wherein the simulating transport comprises tracking movement of units of the acidic fluid between ones of the grid cells.
However, ECONOMIDES teaches defining a final stimulation treatment based on one of the candidate stimulation ECONOMIDES ([Section 2-6 Layered Reservoir Testing] “Layered formations pose special problems for reservoir management that can be best addressed with a layer-by-layer characterization of reservoir parameters. The multilayer transient test is designed to provide the average pressure, productivity index, and well and reservoir parameters for two or more layers commingled in a common wellbore. When a contrast in performance is apparent in commingled layers, this test can determine whether the contrast is due to large variations in layer kh values or to large variations in skin effect. In the former case, there may be implications for waterflood vertical displacement efficiency. In the latter case, there may be a workover treatment that would improve the performance of layers with higher skin factors. Alternatively, the test may show which layer skins have been lowered by a recent stimulation treatment. The sequence of the multilayer transient test is the key to its success. This test merges stabilized and transient flow rate and pressure measurements using a production logging tool. A typical test sequence is illustrated in Fig. 2-14. Beginning.”)
ECONOMIDES also teaches simulating transport of an injected acidic fluid through the formation, wherein the simulating transport comprises tracking movement of units of the acidic fluid between ones of the grid cells ECONOMIDES ([Section 17-3.5. Application to Field Design | Injection Rate] “To ensure wormhole propagation and successful treatment, the acid velocity near the wellbore should be sufficiently high to reach the wormholing regime…For a more accurate design, use of a numerical simulator is required (Bartko et al., 1997). Using a finite-difference simulator enables tracking acid velocity and mineralogy evolution. The amount of rock dissolved as a function of time and acid location can then be calculated in each grid block.”)
It would have been obvious to one of ordinary skill in the art, before the effective filing date, to combine the teachings of ECONOMIDES with WANG and MORRIS, as the references relates to hydrocarbon production using well stimulation techniques. ECONOMIDES would modify WANG and MORRIS wherein simulating transport of an injected acidic fluid through the formation, wherein the simulating transport comprises tracking movement of units of the acidic fluid between ones of the grid cells. The benefits of doing so renewed itself many times since its
inception and has contributed substantial financial benefits to the oil and gas industry. (ECONOMIDES [Preface]).
The combination of WANG, MORRIS and ECONOMIDES does not teach defining a plurality of candidate stimulation treatments comprising injection of an acidic fluid
However, BULEKBAY teaches defining a plurality of candidate stimulation treatments comprising injection of an acidic fluid BULEKBAY ([Abstract] “Methods and systems for enhancing acid fracture conductivity of acid fracture treatments on subterranean formations are provided. An example method of acid fracture treatment includes initiating fracturing of a subterranean formation in which a wellbore is formed to create a formation fracture, after initiating the fracturing for a period of time, injecting an acidic fluid into the wellbore to etch walls of the formation fracture to thereby create fracture conductivity, introducing a gas into the wellbore to foam fluids in the wellbore, and increasing a foam quality of the fluids with time during the treatment. The foam quality is based on a volume of the introduced gas and a total volume of the fluids in the wellbore.”)
It would have been obvious to one of ordinary skill in the art, before the effective filing date, to combine the teachings of BULEKBAY with WANG, MORRIS and ECONOMIDES, as the references relates to hydrocarbon production using well stimulation techniques. BULEKBAY would modify WANG, MORRIS and ECONOMIDES wherein defining a plurality of candidate stimulation treatments comprising injection of an acidic fluid. The benefits of doing so enables to enhance conductivity of an acid fractured wellbore, for example, in a high temperature high stress-depleted carbonate formation. (BULEKBAY [0026]).
WU teaches based on the measurements, simulating fracture propagation in the formation, induced by pressurized fluid injection, the simulating comprising defining grid cells representing a fracture WU ([Section 1.2.2 Coupling Method | pdf page 20 of 89] “Hagoort et al. (1980) developed a mathematical reservoir model to simulate the propagation of waterflood-induced hydraulic fractures in a symmetry element of a waterflood pattern. The model consists of a conventional single-phase reservoir simulator coupled with an analytical fracture model. The model is capable of simulating fracture propagation as a function of injection and production rates or pressures, reservoir and fluid properties, and formation-fracturing pressures… This methodology has been further developed by Ji and Settari (2007) to combine a reservoir model, a geomechanical model, and a fracture geometry model by using the same grid system to model each part. Their model can handle simultaneously a 3-D planar fracture growth, poroelastic effects, varying fracture conductivity and fracture volume in the reservoir model.”)
It would have been obvious to one of ordinary skill in the art, before the effective filing date, to combine the teachings of WU with WANG, MORRIS, ECONOMIDES and BULEKBAY, as the references relates to hydrocarbon production using well stimulation techniques. BULEKBAY would modify WANG, MORRIS, ECONOMIDES and BULEKBAY wherein based on the measurements, simulating fracture propagation in the formation, induced by pressurized fluid injection, the simulating comprising defining grid cells representing a fracture. The benefits of doing allows for correlated permeability in flow direction results in higher conductivity than randomly distributed permeability. (WU [Introduction]).
MOU also teaches simulating etching of rock in the fracture to obtain a model of an etched fracture comprising a plurality of rock pillars representing non-uniform etching in the grid cells MOU ([Section 1.2 Problem Description] “The success of acid fracturing depends on uneven acid etching along the fracture surfaces caused by heterogeneities, such as local mineralogy variation, leakoff variation because of permeability variations, and variations in stress that causes different fracture opening widths. Acid fracture conductivity is created only if less dissolved parts act like pillars to keep the fracture open under closure stress. Heterogeneities likely occur on the scale that neither is used in laboratory measurements of acid fracture conductivity, in which core samples are too small to observe such features, nor in typical acid fracture simulations, in which grid block size is much larger than the scale of heterogeneity due to computational limitations. Channeling characteristics caused by heterogeneities need to have widths on the order of inches for providing lasting conductivity after fracture closure. Such features are sometimes seen in laboratory tests of acid fracture conductivity (Gong, 1997), but this is not common or easily repeatable because the breath of the fracture in lab tests is typically only an inch or two. Current acid fracturing models have a larger grid block size than can practically capture channels that are of the order of inches in breadth. A typical two-dimensional acid fracturing model can only predict uniform dissolution along contour lines fixed by the fracture geometry assumptions. For example, a model based on a PKN or KGD fracture predicts uniform rock dissolution, and hence, created conductivity. Although a three-dimensional model can predict non-uniform etching throughout the fracture domain computational limitations result in dividing the fracture into grid blocks with dimension of several feet to tens of feet on a side.”)
It would have been obvious to one of ordinary skill in the art, before the effective filing date, to combine the teachings of MOU with WANG, MORRIS, ECONOMIDES, BULEKBAY, and WU, as the references relates to hydrocarbon production using well stimulation techniques. MOU would modify WANG, MORRIS, ECONOMIDES, BULEKBAY, and WU wherein simulating etching of rock in the fracture to obtain a model of an etched fracture comprising a plurality of rock pillars representing non-uniform etching in the grid cells. The benefits of doing so develops an intermediate-scale acid fracture model with grid size small enough and the whole dimension big enough to capture local and macro heterogeneity effects and channeling characteristics in acid fracturing. (MOU [Introduction]). Accordingly, claim 1 is rejected based on the combination of these references.
Claim 2
Claim 2 is rejected because the combination of WANG, MORRIS, ECONOMIDES, BULEKBAY, WU, and MOU teaches the claim 1 limitations.
WANG teaches wherein each candidate stimulation treatment comprises a plurality of stages, each having a defined duration, pumping rate, acid type and concentration and proppant type and concentration WANG ([Figure 6], [0012], “FIG. 6 is a flow chart providing an exemplary method of simulating a stimulation operation, performing a stimulation, and/or evaluating the stimulation based on a model.”) See also WANG ([0065] “FIG. 6 illustrates a method 50 of monitoring and/or analyzing an acid stimulation process. The method 50 may include any combination of stimulation, prediction, monitoring, analysis and control of the stimulation. The method 50 is described in conjunction with the stimulation system described in FIGS. 1 and 2 in conjunction with the DTS assembly 28 and/or the surface processing unit 30, although the method 50 may be utilized in conjunction with any suitable combination of temperature sensing devices and processors. The method 50 includes one or more stages 51-56. In one embodiment, the method 50 includes the execution of all of stages 51-56 in the order described. However, certain stages may be omitted, stages may be added, or the order of the stages changed.”) Accordingly, claim 2 is rejected based on the combination of these references.
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Claim 3
Claim 3 is rejected because the combination of WANG, MORRIS, ECONOMIDES, BULEKBAY, WU, and MOU teaches the claim 1 limitations.
The combination of WANG, MORRIS, ECONOMIDES, BULEKBAY, and WU does not explicitly teach wherein the simulating fracture propagation is based on a candidate stimulation treatment, formation properties, and the pressure of injected acidic fluid.
However, MOU teaches wherein the simulating fracture propagation is based on a candidate stimulation treatment, formation properties, and the pressure of injected acidic fluid MOU ([Chapter 1 Introduction] “Carbonate reservoir acid stimulation consists of matrix acidizing, acidizing natural fractures, and acid fracturing. The first two are stimulation methods in which acid is injected at a pressure lower than the formation fracture pressure. The main purpose of matrix acidizing in carbonate is to bypass formation damage near a wellbore by generating wormholes. In case of naturally fractured carbonate reservoirs with or without damage, acidizing can be used to stimulate the reservoirs. It is different from matrix acidizing of un-fractured carbonate formations because the acid mainly flows through natural fractures. As an effective stimulation technique alternative to propped fracturing in carbonate reservoirs all around the world, acid fracturing, initially applied to oilfields in the 1960s, is a stimulation method in which rock dissolution by acid along the surfaces of the hydraulically created fracture or reopened existing fractures is expected to create conductivity after fracture closure. Usually, acid is injected following a viscous pad fluid which is used to initiate a fracture.”)
It would have been obvious to one of ordinary skill in the art, before the effective filing date, to combine the teachings of MOU with WANG, MORRIS, ECONOMIDES, BULEKBAY, and WU, as the references relates to hydrocarbon production using well stimulation techniques. MOU would modify WANG, MORRIS, ECONOMIDES, BULEKBAY, and WU wherein the simulating fracture propagation is based on a candidate stimulation treatment, formation properties, and the pressure of injected acidic fluid. The benefits of doing so develops an intermediate-scale acid fracture model with grid size small enough and the whole dimension big enough to capture local and macro heterogeneity effects and channeling characteristics in acid fracturing. (MOU [Introduction]). Accordingly, claim 3 is rejected based on the combination of these references.
Claim 4
Claim 4 is rejected because the combination of WANG, MORRIS, ECONOMIDES, BULEKBAY, WU, and MOU teaches the claim 1 limitations does not explicitly teach wherein the simulating fracture propagation comprises calculating a fracture size for each of the grid cells.
However, ECONOMIDES teaches wherein the simulating fracture propagation comprises calculating a fracture size for each of the grid cells ECONOMIDES ([Section 3-6 In-Situ Stress Measurement | pdf page 105 of 807] “The amount of fluid and the injection rate used during fluid injection are preferably selected to achieve a predetermined fracture size at the end of the test. This approach, however, requires the use of a fracture propagation model to estimate the fracture geometry during propagation and closure.
It would have been obvious to one of ordinary skill in the art, before the effective filing date, to combine the teachings of ECONOMIDES with WANG and MORRIS, as the references relates to hydrocarbon production using well stimulation techniques. ECONOMIDES would modify WANG and MORRIS wherein the simulating fracture propagation comprises calculating a fracture size for each of the grid cells. The benefits of doing so renewed itself many times since its inception and has contributed substantial financial benefits to the oil and gas industry. (ECONOMIDES [Preface]). Accordingly, claim 4 is rejected based on the combination of these references.
Claim 5
Claim 5 is rejected because the combination of WANG, MORRIS, ECONOMIDES, BULEKBAY, WU, and MOU teaches the claim 1 limitations
The combination of WANG and MORRIS does not teach wherein the simulating transport of an injected acidic fluid comprises using a particle-in-cell method with the grid cells.
However, ECONOMIDES teaches wherein the simulating transport of an injected acidic fluid comprises using a particle-in-cell method with the grid cells ECONOMIDES ([Section A17-3.5 Application to Field Design | Injection Rate] “Table 17-4 shows that pump rates applied for matrix acidizing are usually well above the critical rate for wormholing. Field data generally confirm these results and show that good stimulation can be obtained even with moderate pumping rates over large intervals (see the case study in Sidebar 17B). It is common practice to increase pumping rates as injectivity increases during a treatment. Applying high rates ensures that all portions of the reservoir reach the wormholing regime, even in case of injectivity contrasts between different zones. It also allows sustaining wormhole growth as the stimulation radius increases and the velocity at the acid front decreases. Furthermore, in fissured reservoirs where the purpose of the treatment is to clean up fissures, applying high rates increases the live acid penetration.”)
It would have been obvious to one of ordinary skill in the art, before the effective filing date, to combine the teachings of ECONOMIDES with WANG and MORRIS, as the references relates to hydrocarbon production using well stimulation techniques. ECONOMIDES would modify WANG and MORRIS wherein the simulating transport of an injected acidic fluid comprises using a particle-in-cell method with the grid cells. The benefits of doing so renewed itself many times since its inception and has contributed substantial financial benefits to the oil and gas industry. (ECONOMIDES [Preface]). Accordingly, claim 5 is rejected based on the combination of these references.
Claim 6
Claim 6 is rejected because the combination of WANG, MORRIS, ECONOMIDES, BULEKBAY, WU, and MOU teaches the claim 5 limitations
The combination of WANG and MORRIS does not teach for each of the candidate stimulation treatments, simulating transport of a proppant through the fracture using a particle-in- cell method.
However, ECONOMIDES teaches for each of the candidate stimulation treatments, simulating transport of a proppant through the fracture using a particle-in- cell method ECONOMIDES ([Section 6-5.3 Proppant Transport] “Another effect on proppant placement is fluid migration (Nolte, 1988b) or encapsulation (Cleary and Fonseca, 1992). Fracturing fluids are generally viscoelastic. Although it is beyond the scope of this section to discuss this phenomenon in detail, one of its important effects is to drive proppant to the center of the flow channel. This migration could result in a dense sheet near the center of the channel, surrounded by clear fluid. This has the effect of accelerating particle settling, especially for low proppant concentrations. Unwin and Hammond (1995) presented simulations showing the effect of this migration on proppant placement.
It would have been obvious to one of ordinary skill in the art, before the effective filing date, to combine the teachings of ECONOMIDES with WANG and MORRIS, as the references relates to hydrocarbon production using well stimulation techniques. ECONOMIDES would modify WANG and MORRIS wherein for each of the candidate stimulation treatments, simulating transport of a proppant through the fracture using a particle-in- cell method. The benefits of doing so renewed itself many times since its inception and has contributed substantial financial benefits to the oil and gas industry. (ECONOMIDES [Preface]).Accordingly, claim 6 is rejected based on the combination of these references.
Claim 7
Claim 7 is rejected because the combination of WANG, MORRIS, ECONOMIDES, BULEKBAY, WU, and MOU teaches the claim 6 limitations.
ECONOMIDES teaches for each of the candidate stimulation treatments, simulating compaction of rock in the formation around the proppant ECONOMIDES ([Section 6-8.3 Perforation Friction] “These effects, and their implementation in a fracture simulator, are described in more detail in Romero et al. (1995). Figure 6-15 illustrates the difference between the resulting pressure responses when perforation friction and erosion are included in the calculation and when they are neglected for a PKN geometry model. The pressure increases as expected for a confined fracture, until proppant reaches the perforations. Then the pressure decreases, mainly because of the increase in the discharge coefficient. After about 2000 lbm of sand is injected, the slope becomes positive again, almost paralleling the slope prior to the sand, which indicates a constant discharge coefficient and a slow increase of the perforation diameter.”) See also ECONOMIDES ([Figure 6-15].”)
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ECONOMIDES Figure 6-15 Reference
It would have been obvious to one of ordinary skill in the art, before the effective filing date, to combine the teachings of ECONOMIDES with WANG and MORRIS, as the references relates to hydrocarbon production using well stimulation techniques. ECONOMIDES would modify WANG and MORRIS wherein for each of the candidate stimulation treatments, simulating compaction of rock in the formation around the proppant. The benefits of doing so renewed itself many times since its inception and has contributed substantial financial benefits to the oil and gas industry. (ECONOMIDES [Preface]). Accordingly, claim 7 is rejected based on the combination of these references.
Claim 8
Claim 8 is rejected because the combination of WANG, MORRIS, ECONOMIDES, BULEKBAY, WU, and MOU teaches the claim 6 limitations
The combination of WANG and MORRIS does not teach wherein the simulating compaction of rock comprises calculating compression of rock pillars at each one of a plurality of the grid cells.
However, ECONOMIDES teaches wherein the simulating compaction of rock comprises calculating compression of rock pillars at each one of a plurality of the grid cells ECONOMIDES ([Section 6-8.3 Perforation Friction] “In the revised system, an accumulator attached to the sample maintains constant far-field reservoir pressure during surge flow. This pressure is applied to the sample through a series of auxiliary cores that simulate the flow impedance of the rock surrounding the well. The result is a more realistic simulation of downhole conditions during perforating. The simulated reservoir also allows an indirect measurement of flow rate through the perforation during the surge flow process. By measuring the transient pressure drop across the simulated reservoir, the flow rate through it can be determined from its known impedance. After pseudosteady-state conditions are attained, the flow rates through the two are approximately equal. With proper calibration, this leads to a real-time measurement of the flow rate starting about 0.3 s after detonation. The measurement in turn can be converted to time-resolved values of core flow efficiency (CFE) by dividing the result by the predicted ideal flow rate. Appendix Fig. 12 illustrates the development of CFE with time for a test in Berea sandstone at 1500-psi underbalance. The CFE rises sharply in the first second to 0.8, increases to about 0.85 over the next few seconds and then remains as they move radially away from the perforation. Rock near the perforation is stressed to failure and flows with pseudo-plasticity, whereas rock farther away remains elastic. After the shock dissipates, the failed material returns to an elastic state, although with a lower strength. The net effect of the permanent plastic displacement is a zone of rock that remains under compression even after the shock dissipates.”)
It would have been obvious to one of ordinary skill in the art, before the effective filing date, to combine the teachings of ECONOMIDES with WANG and MORRIS, as the references relates to hydrocarbon production using well stimulation techniques. ECONOMIDES would modify WANG and MORRIS wherein the simulating compaction of rock comprises calculating compression of rock pillars at each one of a plurality of the grid cells. The benefits of doing so renewed itself many times since its inception and has contributed substantial financial benefits to the oil and gas industry. (ECONOMIDES [Preface]). Accordingly, claim 8 is rejected based on the combination of these references.
Claim 9
Claim 9 is rejected because the combination of WANG, MORRIS, ECONOMIDES, BULEKBAY, WU, and MOU teaches the claim 1 limitations.
The combination of WANG and MORRIS does not teach for each of the candidate stimulation treatments, simulating the consumption of acid by etching of rock.
However, ECONOMIDES teaches for each of the candidate stimulation treatments, simulating the consumption of acid by etching of rock ECONOMIDES ([6-9.4 Energy Balance Fraturing] “The acid reaction rate at a surface is thus a complex function of the activities of all species involved in the reaction. Detailed modeling of the reaction in terms of these activities is not required for a hydraulic fracture simulator, because of the large amount of uncertainty in the other parameters. Instead, the reaction rate can be assumed to be governed by the simple equation for the rate of acid consumption r (Settari, 1993).
It would have been obvious to one of ordinary skill in the art, before the effective filing date, to combine the teachings of ECONOMIDES with WANG and MORRIS, as the references relates to hydrocarbon production using well stimulation techniques. ECONOMIDES would modify WANG and MORRIS wherein for each of the candidate stimulation treatments, simulating the consumption of acid by etching of rock. The benefits of doing so renewed itself many times since its inception and has contributed substantial financial benefits to the oil and gas industry. (ECONOMIDES [Preface]). Accordingly, claim 9 is rejected based on the combination of these references.
Claim 10
Claim 10 is rejected because the combination of WANG, MORRIS, ECONOMIDES, BULEKBAY, WU, and MOU teaches the claim 1 limitations.
The combination of WANG and MORRIS does not teach wherein the simulating transport comprises maintaining data records corresponding to units of fluid.
However, ECONOMIDES teaches wherein the simulating transport comprises maintaining data records corresponding to units of fluid ECONOMIDES ([Section 6-12 Pressure History Matching] “The only direct output from the formation during a fracture treatment is the pressure history measured during and after pumping the treatment. Chapter 9 discusses the interpretation of these pressure records in detail. However, these analyses can be only quantitatively accurate for relatively simple fracture geometries. This section considers the application of a formal theory of inversion (see Sidebar 6M) to complement qualitative interpretation and to increase the quantitative information available from the pressure record.”)
It would have been obvious to one of ordinary skill in the art, before the effective filing date, to combine the teachings of ECONOMIDES with WANG and MORRIS, as the references relates to hydrocarbon production using well stimulation techniques. ECONOMIDES would modify WANG and MORRIS wherein the simulating transport comprises maintaining data records corresponding to units of fluid. The benefits of doing so renewed itself many times since its inception and has contributed substantial financial benefits to the oil and gas industry. (ECONOMIDES [Preface]). Accordingly, claim 10 is rejected based on the combination of these references.
Claim 11
Claim 11 is rejected because the combination of WANG, MORRIS, ECONOMIDES, BULEKBAY, WU, and MOU teaches the claim 10 limitations
The combination of WANG and MORRIS does not teach wherein the simulating transport comprises tracking positions of the units of fluid at ones of the grid cells in a plurality of time steps.
However, ECONOMIDES teaches wherein the source code defines instruction sequences for more than one execution thread ECONOMIDES ([Section 6-9.8 Acid Fracturing: Fracture Geomtery Model] “The movement of acid perpendicular to the fracture wall is considered in this section. The preceding sections discuss the fluid flow equations typically solved in fracture models. Acid movement within the fracture can be modeled similarly to the movement of proppant. For a fracture simulator to simulate acid fracturing treatments accurately, several specific requirements must be met relating to, • fluid tracking in the fracture and reservoir • recession of the active fracture length and • effect of etching on the relation between pressure and width. Although typical fluid flow calculation schemes use a coarse grid (about 10 elements), accurate fluid front tracking can be obtained only by following up to 50 fluid stages. Typical treatments include only about 10 different stages, but stages can be subdivided for better tracking of the large gradients that may occur inacid concentration within a single stage.”)
It would have been obvious to one of ordinary skill in the art, before the effective filing date, to combine the teachings of ECONOMIDES with WANG and MORRIS, as the references relates to hydrocarbon production using well stimulation techniques. ECONOMIDES would modify WANG and MORRIS wherein the source code defines instruction sequences for more than one execution thread. The benefits of doing so renewed itself many times since its
inception and has contributed substantial financial benefits to the oil and gas industry. (ECONOMIDES [Preface]). Accordingly, claim 11 is rejected based on the combination of these references.
Claim 12
Claim 12 is rejected because the combination of WANG, MORRIS, ECONOMIDES, BULEKBAY, WU, and MOU teaches the claim 10 limitations
The combination of WANG and MORRIS does not teach for each of the candidate stimulation treatments, tracking a consumed portion of acid in ones of the data records corresponding to units of fluid.
However, ECONOMIDES teaches for each of the candidate stimulation treatments, tracking a consumed portion of acid in ones of the data records corresponding to units of fluid ECONOMIDES ([Section 6-10 Multilayer Fracturing] “Figure 6-21 shows an example of a multilayer fracture treatment modeled as a set of PKN fractures. The fluid partitioning was measured using a spinner flowmeter, and the downhole pressure was recorded. The model accurately captures the behavior of the system.”)
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DOWEL Figure 6-21 Reference
See also ECONOMIDES ([Section 6-9.7 Acid Reaction Model] “If reaction occurs, the acid concentration varies across the fracture width, and the surface concentration is less than the bulk acid concentration. The surface concentration is such that the amount consumed at the surface is balanced by transport to the surface by diffusion. The wall concentration for a given bulk concentration is obtained by equating the right-hand sides of Eqs. 6-134 and 6-138 to obtain
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.”)
It would have been obvious to one of ordinary skill in the art, before the effective filing date, to combine the teachings of ECONOMIDES with WANG and MORRIS, as the references relates to hydrocarbon production using well stimulation techniques. ECONOMIDES would modify WANG and MORRIS wherein for each of the candidate stimulation treatments, tracking a consumed portion of acid in ones of the data records corresponding to units of fluid. The benefits of doing so renewed itself many times since its inception and has contributed substantial financial benefits to the oil and gas industry. (ECONOMIDES [Preface]). Accordingly, claim 12 is rejected based on the combination of these references.
Claim 13
Claim 13 is rejected because WANG teaches a plurality of sensors for measuring characteristics of the formation WANG ([0022] “Various sensors or sensing assemblies may be disposed in the system to measure downhole parameters and conditions. For example, pressure and/or temperature sensors may be disposed at the production string at one or more locations ( e.g., at or near injection devices 24). Such sensors may be configured as discrete sensors such as pressure/temperature sensors or distributed sensors. The DTS assembly 28 is configured to measure temperature continuously or intermittently along a selected length of the string 12, and includes at least one optical fiber that extends along the string 12, e.g., on an outside surface of the string or the tubular 18. Temperature measurements collected via the DTS assembly 28 can be used in a model to estimate fluid flow parameters in the string 12 and the borehole 14, e.g., to estimate acid distribution in the formation 16 and/or production zones.”)
WANG also teaches a computing device comprising a processor and a computer-readable storage WANG ([0023] “In one embodiment, theDTSassembly28, the injection assemblies 24, and/or other components are in communication with one or more processors, such as a surface processing unit 30 and/or a downhole electronics unit 32. The communication incorporates any of various transmission media and connections, such as wired connections, fiber optic connections and wireless connections. The surface processing unit 30, electronics unit 32 and/or DTS assembly include components as necessary to provide for storing and/or processing data collected from various sensors therein. Exemplary components include, without limitation, at least one processor, storage, memory, input devices, output devices and the like. For example, the surface processing unit includes a processor 34 including a memory 36 and configured to execute software for processing measurements and generating a model as described below.”)
WANG also teaches computer-readable instructions stored on the computer-readable storage, for simulating a plurality of candidate stimulation treatments comprising injection of an acidic fluid WANG ([0096] “In support of the teachings herein, various analyses and/or analytical components may be used, including digital and/or analog systems. The system may have components such as a processor, storage media, memory, input, output, communications link (wired, wireless, pulsed mud, optical or other), user interfaces, software programs, signal processors ( digital or analog) and other such components (such as resistors, capacitors, inductors and others) to provide for operation and analyses of the apparatus and methods disclosed herein in any of several manners well-appreciated in the art. It is considered that these teachings may be, but need not be, implemented in conjunction with a set of computer executable instructions stored on a computer readable medium, including memory (ROMs, RAMs), optical (CD-ROMs), or magnetic ( disks, hard drives), or any other type that when executed causes a computer to implement the method of the present invention. These instructions may provide for equipment operation, control, data collection and analysis and other functions deemed relevant by a system designer, owner, user or other such personnel, in addition to the functions described in this disclosure.”) See also WANG ([0042-0047].) The combination of WANG and MORRIS does not explicitly teach a rock-bending model for simulating compaction of rock in the formation based on an etched fracture size for each one of the grid cells, to obtain a compacted fracture size associated with each one of the grid cells or instructions for evaluating a predicted fluid conductivity associated with each of the candidate stimulation treatments, based on the simulating, wherein one of the candidate simulation treatments is defined as a final simulation treatment in response to the predicted fluid conductivity meeting performance criteria.
ECONOMIDES also teaches a rock-bending model for simulating compaction of rock in the formation based on an etched fracture size for each one of the grid cells, to obtain a compacted fracture size associated with each one of the grid cells ECONOMIDES ([Section 3.3.2] “To perform a micro-hydraulic fracture in an openhole, the selected test interval is isolated from the surrounding well using a packer arrangement (Fig. 3-22). Fluid is then injected in the interval at a constant flowrate. During injection, the wellbore is pressurized up to the initiation of a tensile fracture. Initiation is usually recognized by a breakdown on the pressure versus time record, hence the name breakdown pressure (Fig. 3-23). In practice, breakdown is not always obtained. Initiation could also occur prior to breakdown. After the initial breakdown, injection should continue until the pressure stabilizes. Injection is then stopped and the pressure allowed to decay. The fracturing fluid is usually a low-viscosity fluid for low permeability zones or a drilling mud for zones with higher ranges of permeability. Usually less than 100 gal is injected into the formation at flow rates ranging from 0.25 to 25 gal/min. The amount of fluid and the injection rate used during fluid injection are preferably selected to achieve a predetermined fracture size at the end of the test. This approach, however, requires the use of a fracture propagation model to estimate the fracture geometry during propagation and closure.”)
ECONOMIDES also teaches instructions for evaluating a predicted fluid conductivity associated with each of the candidate stimulation treatments, based on the simulating, wherein one of the candidate simulation treatments is defined as a final simulation treatment in response to the predicted fluid conductivity meeting performance criteria ECONOMIDES ([Section 12-1 Introduction] “Evaluation of the fracture geometry, well deliverability and reservoir performance of fractured wells with post-treatment well and reservoir responses has been extensively investigated. Post-treatment measurements of the created fracture geometry have been obtained with various logging and microseismic fracture mapping techniques. Pressure transient analysis has been used as a posttreatment evaluation procedure for estimating the fracture extension into the reservoir as well as for obtaining estimates of the fracture conductivity and reservoir properties. With the reservoir and fracture parameter estimates obtained with these and various other post-treatment analysis techniques, a production systems analysis can be performed to determine the post-treatment deliverability of the fractured well.”)
It would have been obvious to one of ordinary skill in the art, before the effective filing date, to combine the teachings of ECONOMIDES with WANG and MORRIS, as the references relates to hydrocarbon production using well stimulation techniques. ECONOMIDES would modify WANG and MORRIS wherein instructions for evaluating a predicted fluid conductivity associated with each of the candidate stimulation treatments, based on the simulating, wherein one of the candidate simulation treatments is defined as a final simulation treatment in response to the predicted fluid conductivity meeting performance criteria. The benefits of doing so renewed itself many times since its
inception and has contributed substantial financial benefits to the oil and gas industry. (ECONOMIDES [Preface]).
The combination of WANG, MORRIS, ECONOMIDES, BULEKBAY does not explicitly teach an etching model for simulating etching of rock in the fracture to obtain a representation of an etched fracture comprising a plurality of rock pillars from non-uniform etching in the grid cells.
However, WU teaches an etching model for simulating etching of rock in the fracture to obtain a representation of an etched fracture comprising a plurality of rock pillars from non-uniform etching in the grid cells WU ([Section 4.2 Case 2: Field Example] “Using E-StimPlan, the fracture geometry just before the first acid injection stage is presented in Figure 4.11. The fracture width assigned to each node was output to a file which could be read by the acid etching model. Etching is calculated during this displacement to summarize the acid-etched width created during the entire gelled acid stage. According to the work on this case done by Oeth (Oeth, 2013), the total conductivity is calculated by adding all the etched-width computed after each acid injection stage. Figure 4.13 illustrates the total acid-etched width map (Oeth, 2013). Figure 4.14 and Table 4.6 show the total conductivity after acid injection treatment.”)
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WU Figure 4.11 Reference
It would have been obvious to one of ordinary skill in the art, before the effective filing date, to combine the teachings of WU with WANG, MORRIS, ECONOMIDES and BULEKBAY, as the references relates to hydrocarbon production using well stimulation techniques. WU would modify WANG, MORRIS, ECONOMIDES and BULEKBAY wherein an etching model for simulating etching of rock in the fracture to obtain a representation of an etched fracture comprising a plurality of rock pillars from non-uniform etching in the grid cells. The benefits of doing allows for correlated permeability in flow direction results in higher conductivity than randomly distributed permeability. (WU [Introduction]).
The combination of WANG, MORRIS, ECONOMIDES, BULEKBAY, and WU does not explicitly teach a fracture propagation model for simulating fracture propagation induced by pressurized fluid injection in the formation, by defining grid cells representing a fracture or a transport model for simulating transport of an injected acidic fluid through the formation by tracking movement of units of the acidic fluid between ones of the grid cells.
However, MOU teaches a fracture propagation model for simulating fracture propagation induced by pressurized fluid injection in the formation, by defining grid cells representing a fracture MOU ([Section 1.1 Background pdf page 19 of 24] “The primary objectives of designing acid fracturing treatments are to optimize live acid penetration distance and conductivity. The main parameters in a design include acid type and strength, acid injection volume, and injection rate of the acid. Acid fracture conductivity, a measure of the capacity for fluid flow through a fracture, is influenced by the amount of rock dissolved, the fracture surface etching patterns, the rock strength, and the closure stress. If a very small amount of rock is dissolved on the fracture surfaces, very little conductivity will be obtained because of very small fracture width. Uniform rock dissolution along the fracture gives little conductivity because the fracture will close under closure stress. By its nature, the success of acid fracturing depends on uneven acid etching along the fracture surface caused by heterogeneities such as variations in local mineralogy, variations in leakoff behavior, and variations in local stress that cause different fracture opening widths along the surfaces. Conductivity is created only if the less dissolved parts act like pillars to keep more dissolved parts open. As a tool to design and optimize acid fracturing treatments, an acid fracturing simulator generally includes two parts: a fracture propagation module, which traces the fracture propagation and can be achieved by using existing hydraulic fracturing models although acid/rock reaction and leakoff behavior make it different from fracture propagation in hydraulic fracturing, and an acid transport module, which traces acid flow in the fracture.”)
MOU also teaches a transport model for simulating transport of an injected acidic fluid through the formation by tracking movement of units of the acidic fluid between ones of the grid cells MOU ([Section 1.1 Background pdf page 19 of 24] “a tool to design and optimize acid fracturing treatments, an acid fracturing simulator generally includes two parts: a fracture propagation module, which traces the fracture propagation and can be achieved by using existing hydraulic fracturing models although acid/rock reaction and leakoff behavior make it different from fracture propagation in hydraulic fracturing, and an acid transport module, which traces acid flow in the fracture. Acid fracture simulators calculate fracture conductivity using correlations, developed based on laboratory measurements of fracture conductivity on samples which are a few inches in every direction. Acid fracture conductivity correlations describe how fracture conductivity changes with closure stress. They include two parts: fracture conductivity at zero closure stress and the rate of conductivity change with closure stress.
It would have been obvious to one of ordinary skill in the art, before the effective filing date, to combine the teachings of MOU with WANG, MORRIS, ECONOMIDES, BULEKBAY, and WU, as the references relates to hydrocarbon production using well stimulation techniques. MOU would modify WANG, MORRIS, ECONOMIDES, BULEKBAY, and WU wherein transport model for simulating transport of an injected acidic fluid through the formation by tracking movement of units of the acidic fluid between ones of the grid cells. The benefits of doing so develops an intermediate-scale acid fracture model with grid size small enough and the whole dimension big enough to capture local and macro heterogeneity effects and channeling characteristics in acid fracturing. (MOU [Introduction]). Accordingly, claim 13 is rejected based on the combination of these references.
Claim 14
Claim 14 is rejected because it is the system embodiment of claim 2, with similar limitations to claim 2, and is such rejected using the same reasoning found in claim 2.
Claim 15
Claim 15 is rejected because the combination of WANG, MORRIS, ECONOMIDES, BULEKBAY, WU, and MOU teaches the claim 13 limitations
The combination of WANG and MORRIS does not teach explicitly teach wherein the simulating fracture propagation comprises defining a formation model based on measurements from the plurality of sensors.
However, ECONOMIDES teaches wherein the simulating fracture propagation comprises defining a formation model based on measurements from the plurality of sensors ECONOMIDES ([Section 11-4.6 Vital Signs from Sensors] “The monitoring of hydraulic fracture treatments has evolved from simple pressure strip charts to sophisticated computer recording and display. The information displayed by these instruments provides the supervising engineers with diagnostics on how the treatment is proceeding. Real-time execution decisions are made during the treatment based on this information. Sensors acquire input data to track and account for the numerous operations taking place on location. Most of the parameters required for evaluating a fracturing treatment can be followed with sensors. Pressure, density, rate, temperature, pH value and viscosity are some of the more common parameters displayed and recorded.
It would have been obvious to one of ordinary skill in the art, before the effective filing date, to combine the teachings of ECONOMIDES with WANG and MORRIS, as the references relates to hydrocarbon production using well stimulation techniques. ECONOMIDES would modify WANG and MORRIS wherein the simulating fracture propagation comprises defining a formation model based on measurements from the plurality of sensors. The benefits of doing so renewed itself many times since its inception and has contributed substantial financial benefits to the oil and gas industry. (ECONOMIDES [Preface]). Accordingly, claim 15 is rejected based on the combination of these references.
Claim 16
Claim 16 is rejected because the combination of WANG, MORRIS, ECONOMIDES, BULEKBAY, WU, and MOU teaches the claim 13 limitations.
The combination of WANG and MORRIS does not teach wherein the rock bending model includes instructions for simulating bending of rock around proppant.
However, ECONOMIDES teaches wherein the rock bending model includes instructions for simulating bending of rock around proppant ECONOMIDES ([Section 1-3.5 Hydraulic Fracturing in Production Engineering] “Optimal fracture conductivity With advent of the TSO technique especially in high-permeability, soft formations (called frac and pack), it is possible to create short fractures with unusually wide propped widths. In this context a strictly technical optimization problem can be formulated: how to select the length and width if the propped fracture volume is given. The following example from Valkó and Economides (1995) addresses this problem, using the method derived by Prats (1961). • Example of optimal fracture conductivity Consider the following reservoir and well data: k = 0.4 md, h = 65 ft, re/rw = 1000, μ = 1 cp, pe = 5000 psi and pwf = 3000 psi. Determine the optimal fracture half-length xf, optimal propped width w and optimal steady-state production rate if the volume of the propped fracture is Vf = 3500 ft3. Use a value of 10,000 md for the fracture permeability kf, taking into account possible damage to the proppant, and assume that the created fracture height equals the formation thickness. Use the Cinco-Ley and Samaniego-V. (1981b) graph (Fig. 1-11), which assumes pseudoradial flow.”)
It would have been obvious to one of ordinary skill in the art, before the effective filing date, to combine the teachings of ECONOMIDES with WANG and MORRIS, as the references relates to hydrocarbon production using well stimulation techniques. ECONOMIDES would modify WANG and MORRIS wherein the rock bending model includes instructions for simulating bending of rock around proppant. The benefits of doing so renewed itself many times since its
inception and has contributed substantial financial benefits to the oil and gas industry. (ECONOMIDES [Preface]). Accordingly, claim 16 is rejected based on the combination of these references.
Claim 17
Claim 17 is rejected because it is the system embodiment of claim 8, with similar limitations to claim 8, and is such rejected using the same reasoning found in claim 8.
Claim 18
Claim 18 is rejected because it is the system embodiment of claim 9, with similar limitations to claim 9, and is such rejected using the same reasoning found in claim 9.
Claim 19
Claim 19 is rejected because it is the system embodiment of claim 6, with similar limitations to claim 6, and is such rejected using the same reasoning found in claim 6.
Claim 20
Claim 20 is rejected because the combination of WANG, MORRIS, ECONOMIDES, BULEKBAY, WU, and MOU teaches the claim 13 limitations.
The combination of WANG and MORRIS does not explicitly teach wherein the simulating consumption of etching comprises maintaining a data records corresponding to units the acidic fluid, the data records including a proportion of spent acid.
However, ECONOMIDES teaches wherein the simulating consumption of etching comprises maintaining a data records corresponding to units the acidic fluid, the data records including a proportion of spent acid ECONOMIDES ([Section 14-2 Damage Characterization] “All equipment to be used in stimulation operations should be properly maintained to perform reliably and accurately. As discussed in Section 13-5 for treatment design, adherence to the design is required to increase the chance of success. Calibration of all measuring devices, such as transducers and flowmeters, should be a regular part of maintenance procedures. Calibration conditions should mimic operating conditions to the extent required to properly calibrate the equipment. Sufficient inventories of spare parts should be available to make maintenance repairs quickly. Calibration tests should be conducted routinely and the results documented. Careful recording of events during the treatment should be made, including records of unusual observations by operations personnel (McLeod and Coulter, 1969). Over the past decade, the emphasis on improved monitoring and recording equipment and QC rather than pumping and mixing equipment has resulted in better records for post job treatment evaluation and improved matrix success.”)
It would have been obvious to one of ordinary skill in the art, before the effective filing date, to combine the teachings of ECONOMIDES with WANG and MORRIS, as the references relates to hydrocarbon production using well stimulation techniques. ECONOMIDES would modify WANG and MORRIS wherein the simulating consumption of etching comprises maintaining a data records corresponding to units the acidic fluid, the data records including a proportion of spent acid. The benefits of doing so renewed itself many times since its
inception and has contributed substantial financial benefits to the oil and gas industry. (ECONOMIDES [Preface]). Accordingly, claim 20 is rejected based on the combination of these references.
Claim 21
Claim 21 is rejected because the combination of WANG, MORRIS, ECONOMIDES, BULEKBAY, WU, and MOU teaches the claim 13 limitations.
The combination of WANG and MORRIS does not explicitly teach wherein the simulating transport comprises tracking positions of the units of fluid at ones of the grid cells in a plurality of time steps.
However, ECONOMIDES teaches wherein the simulating transport comprises tracking positions of the units of fluid at ones of the grid cells in a plurality of time steps ECONOMIDES ([Section 17-3.5 Application to Field Design] “For a more accurate design, use of a numerical simulator is required (Bartko et al., 1997). Using a finite-difference simulator enables tracking acid velocity and mineralogy evolution. The amount of rock dissolved as a function of time and acid location can then be calculated in each grid block using local conditions of mineralogy and acid concentration and velocity. Reaction parameters and the rate of wormhole growth are correlated from experimental data obtained with linear cores for a broad range of flow and acid conditions. Tracking the wormhole propagation front allows calculating a skin effect factor s, assuming an infinite permeability in the stimulated area:
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.”)
It would have been obvious to one of ordinary skill in the art, before the effective filing date, to combine the teachings of ECONOMIDES with WANG and MORRIS, as the references relates to hydrocarbon production using well stimulation techniques. ECONOMIDES would modify WANG and MORRIS wherein the simulating transport comprises tracking positions of the units of fluid at ones of the grid cells in a plurality of time steps. The benefits of doing so renewed itself many times since its inception and has contributed substantial financial benefits to the oil and gas industry. (ECONOMIDES [Preface]). Accordingly, claim 21 is rejected based on the combination of these references.
Claim 22
Claim 22 is rejected because it is the method embodiment of claim 1, with similar limitations to claim 1, and is such rejected using the same reasoning found in claim 1.
ECONOMIDES also teaches comprising injection of a slurry comprising acidic fluid and proppant ECONOMIDES ([Section 1-7.2 Hydraulic Fracturing] “Unlike matrix stimulation, fracturing can be one of the more complex procedures performed on a well (Fig. 1-23). This is due in part to the high rates and pressures, large volume of materials injected, continuous blending of materials and large amount of unknown variables for sound engineering design. The fracturing pressure is generated by single action reciprocating pumping units that have between 700 and 2000 hydraulic horsepower (Fig. 1-24). These units are powered by diesel, turbine or electric engines. The pumps are purpose-built and have not only horsepower limits but job specification limits. These limits are normally known (e.g., smaller plungers provide a higher working pressure and lower rates). Because of the erosive nature of the materials (i.e., proppant) high pump efficiency must be maintained or pump failure may occur. The limits are typically met when using high fluid velocities and high proppant concentrations (+18 ppg). There may be numerous pumps on a job, depending on the design. Mixing equipment blends the fracturing fluid system, adds the proppant and supplies this mixture to the high-pressure pumps. The slurry can be continuously mixed by the equipment (Fig. 1-25) or batch mixed in the fluid storage tanks. The batch-mixed fluid is then blended with proppant in a continuous stream and fed to the pumps.”)
ECONOMIDES also teaches simulating fracture propagation and fluid- proppant slurry transport in the formation, using a particle-in-cell method ECONOMIDES ([Section 6-5 Proppant Placement] “Density differences between fluids may result in the denser fluid flowing under the lighter fluid or the lighter fluid overriding the denser fluid. This phenomenon, known as convection or gravitational flow, is important in many fields, such as saltwater intrusion under fresh water (Badon Ghyben, 1888; Herzberg, 1901). In fracturing, it may be relevant if a high density slurry stage flows under a previously pumped stage or pad, as well as for other 2D aspects of fluid flow, such as those considered by Clifton and Wang (1988). The last (gravitational) term on the right-hand side of Eq. 6-105 is the convective term. This can be treated as a source term, just as the other two terms are storage or sink terms, resulting from width change and leakoff. Baree and Conway (1994), Unwin and Hammond (1995) and Smith and Klein (1995) showed that this is generally not significant for most properly designed fracturing treatments. Smith and Klein showed that if excess pad was pumped, the fluid flow after pumping stops (i.e., afterflow) could lead to convection until the pad leaked off. Also, Eq. 6-105 shows the extreme sensitivity of convection to fracture width. If the width is large (e.g., in a low-modulus rock), convection may be more critical. Fortunately, such low moduli are usually associated with high permeabilities, in which case TSO designs and rapid leakoff after shut-in effectively prevent convection. Cleary and Fonseca (1992) presented a dimensionless number that reflects the ratio of buoyant and viscous forces. This ratio can be used to estimate the effect of different conditions on the severity of convection. Finally, Clark and Courington’s (1994) and Clark and Zhu’s (1994) experiments on convection largely verify the theoretical and numerical results described here.”)
It would have been obvious to one of ordinary skill in the art, before the effective filing date, to combine the teachings of ECONOMIDES with WANG and MORRIS, as the references relates to hydrocarbon production using well stimulation techniques. ECONOMIDES would modify WANG and MORRIS wherein simulating fracture propagation and fluid- proppant slurry transport in the formation, using a particle-in-cell method. The benefits of doing so renewed itself many times since its inception and has contributed substantial financial benefits to the oil and gas industry. (ECONOMIDES [Preface]). Accordingly, claim 22 is rejected based on the combination of these references.
Conclusion
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/M.K.V./Examiner, Art Unit 2186
/RENEE D CHAVEZ/Supervisory Patent Examiner, Art Unit 2186