DETAILED ACTION
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 .
Priority
Application 17/963,827 filed on 10/11/2022 is a CON of PCT/US2021/026402 filed on 04/08/2021 and claims benefit of 63/009,097 filed on 04/13/2020.
Response to Amendment
This office action is in response to amendments submitted on 12/15/2025 wherein claims 1-5 are pending.
Claim Rejections - 35 USC § 112
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claim1 is rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
Regarding claim 1: Applicant claims, “determining a relationship between (ii) a delay time of the first observable measured pressure response in the well after a change in the fractional choke opening” (line 10 and 12-13). Examiner is uncertain as to what the determined relationship is between as only a delay time has been claimed in this limitation therefore the claim is indefinite.
Regarding claims 2-5: Claims 2-5 are also rejected under 35 USC 112(b) as they depend from claim 1.
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.
Claims 1-5 are rejected under 35 U.S.C. 103 as being unpatentable over Brana et al., U.S. Pub. No. 2016/0102511 A1 in view of Hardt et al., U.S. Pub. No. 2017/0037690 A1, in view of Dietrich et al., herein after Dietrich, U.S. Pub. No. 2021/0230966 A1.
Regarding Independent claim 1 Brana teaches:
“A method for tuning a managed pressure drilling system comprising a variable orifice choke operating to controllably restrict fluid flow from a drilling well” (Brana, Abstract.)
“the method comprising: (a) determining a relationship between change in measured flow rate of fluid through the choke with respect to fractional choke opening at a constant pressure drop across the choke in a managed pressure drilling system installed on a drilling unit” (Brana, fig. 5, ¶ 0036-¶ 0037, ¶ 0077, ¶ 0079-¶ 0082: Brana teaches “Fluid leaving the wellbore 16 flows through the automated choke manifold” (¶ 0037) where the “automated choke manifold” has “a mass flow meter 24, pressure sensors (not shown) (¶ 0036). “Software components of the control system 100 then compare the flowrate in and out of the wellbore 16, the injection pressure (or standpipe pressure), the surface backpressure (measured upstream from the drilling chokes 22), the position of the chokes 22, and the mud density. Comparing these variables, the control system 100 identifies minute downhole influxes and losses on a real-time basis to manage the annulus pressure during drilling” (Brana, ¶ 0037) where “Comparing these variables” discloses “determining a relationship” between the “change in measured flow rate of fluid through the choke with respect to fractional choke opening at a constant pressure drop across the choke.” In addition, the “annular pressure management in the system 10” is provided that “maintains a predefined pressure in the wellbore 16” disclosing a “constant pressure drop across the choke.” Moreover, “flow is used for the parameter in the error so that the error is calculated between the measured flow 114 and the set point flow 112” (¶ 0079), “a gain factor is dynamically calculated based on the magnitude of the error” (¶ 0080) and applied to the calculated error to “determine a choke position adjustment” which “is added to the current position 120 of the choke (block 126), which gives a new choke position 128 relative to the previous position”(¶ 0081), after this “the entire process of the control 110 repeats itself in which the new choke position 128 becomes the current position so a new adjustment is calculated as needed” (¶ 0082) where the change in the choke position discloses a relationship between the “change in measured flow rate of fluid through the choke with respect to fractional choke opening” as a change in the “measured flow rate” results from a change in the choke position. “Limits are applied to the new choke position 128 to maintain range integrity (0-100%)” (¶ 0081) where the “control 110 calculates the position of the choke 22 (e.g., in terms of percent open 0-100% (¶ 0067) disclosing a “fractional choke opening.”)
“(b) determining a relationship between change in measured fluid pressure in the well and change in the fractional choke opening at a constant fluid flow rate into the well in the installed managed pressure drilling system” (Brana, fig. 5, ¶ 0036-¶ 0038, ¶ 0044, ¶ 0056-¶ 0057, ¶ 0064, ¶ 0067, ¶ 0077-¶ 0078, ¶ 0080-¶ 0082: Brana teaches “Fluid leaving the wellbore 16 flows through the automated choke manifold” (¶ 0037) where the “automated choke manifold” has “a mass flow meter 24, pressure sensors (not shown) (¶ 0036). “Software components of the control system 100 then compare the flowrate in and out of the wellbore 16, the injection pressure (or standpipe pressure), the surface backpressure (measured upstream from the drilling chokes 22), the position of the chokes 22, and the mud density. Comparing these variables, the control system 100 identifies minute downhole influxes and losses on a real-time basis to manage the annulus pressure during drilling” (Brana, ¶ 0037) where “Comparing these variables” discloses “determining a relationship” between the “change in the measured fluid pressure in the well and change in the fractional choke opening at a constant fluid flow rate.” In addition, “using the choke manifold 20 to apply surface backpressure within the closed loop, the control system 100 can produce a reciprocal change in bottomhole pressure” (¶ 0038, see also ¶ 0056-¶ 0057) therefore the “surface backpressure” discloses a “pressure in the well.” Brana teaches maintaining a flow-in, flow-out equilibrium for a specified time ¶ 0044) disclosing “a constant fluid flow rate into the well.” Moreover, “pressure is used for the parameter in the error so that the error is calculated between the measured pressure 114 and the set point pressure 112” (¶ 0078), “a gain factor is dynamically calculated based on the magnitude of the error” (¶ 0080) and applied to the calculated error to “determine a choke position adjustment” which “is added to the current position 120 of the choke (block 126), which gives a new choke position 128 relative to the previous position”(¶ 0081), after this “the entire process of the control 110 repeats itself in which the new choke position 128 becomes the current position so a new adjustment is calculated as needed” (¶ 0082) where the change in the choke position characterizes the “change in measured fluid pressure in the well with respect to change in the fractional choke opening” as a change in the “measured fluid pressure” results in a change in the choke position. “Limits are applied to the new choke position 128 to maintain range integrity (0-100%)” (¶ 0081) and the “position of the choke” is “in terms of percent open 0-100% (¶ 0064) and “control 110 calculates the position of the choke 22 (e.g., in terms of percent open 0-100% (¶ 0067) disclosing a “fractional choke opening.”)
“(c) determining a relationship between (i) a response time of a first observable change in measured pressure in the well and changes in the fractional choke opening” (Brana, fig. 7B, ¶ 0101-¶ 0105: Fig. 7B depicts a response curve (152) using a standard PID control (¶ 0102) and a response curve 155 using the “disclosed choke control” (¶ 0103) where the “choke control” discloses “changes in the fractional choke opening.” In comparison to the increase of the PID control system, the choke control increase 156 is more rapid (response time) reaching and maintaining the set point of 140 psi (¶ 0104) and the decrease 157 is smoother and more rapid (response time) than decrease 154 of the PID control disclosing “determining a relationship between a response time of measured pressure and changes in the fractional choke opening.”)
While Brana teaches “using the choke manifold 20 to apply surface backpressure within the closed loop, the control system 100 can produce a reciprocal change in bottomhole pressure” (¶ 0038, see also ¶ 0056-¶ 0057) disclosing a “pressure in the well” however, Brana does not teach measuring the “fluid pressure in the well.”
Hardt teaches a measuring device 127 for measuring the pressure downhole (¶ 0021).
Brana teaches using measured pressure and a pressure set point to determine the adjustment of the choke in order to adjust the pressure. Additionally, Brana teaches a blow out preventor which a person of ordinary skill in the art would understand contains pressure sensors, therefore it would have been obvious for one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the method for tuning a managed pressure drilling system as taught by Brana by including well pressure measurements as taught by Hardt because there are fewer manipulations with direct measurements and therefore direct measurements provide a system with greater accuracy and reliability.
Brana teaches:
“determining a relationship between (iii) a surface back pressure applied to the well and the fractional choke opening in the installed managed pressure drilling system” (Brana, ¶ 0107: the choke positions (fractional choke opening) are adjusted for example, opened, to “maintain the surface back pressure within the desired drilling window” (¶ 0107) disclosing “determining a relationship between a surface back pressure applied to the well and to the fractional choke opening” as the back pressure is maintained due to the adjustment of the choke. Moreover, Fig. 1 depicts a Managed Pressure Drilling (MPD) system 10 which includes a choke manifold 20 with chokes 22 disclosing “the fractional choke opening in the installed managed pressure drilling system”).
“using the determined relationships in at least one of (a), and (b) and the determined relationships in (c) to calculate control parameters for a proportional integral differential controller having as a controlled output the fractional choke opening and as a control input the fluid pressure in the well before the choke” (Brana, ¶ 0036-¶ 0037, ¶ 0063-¶ 0064, ¶ 0074-¶ 0077: Brana teaches “the processing unit 102 can operate a choke control 110 according to the present disclosure for monitoring, tuning, and controlling the choke(s) 22” (¶ 0074) where “data related to the flow coefficient of the choke 22 is used as a tuning factor within a choke control” (¶ 0063) where “the flow coefficient (Cv) . . . relates flow rate of a choke valve to the differential pressure produced” (¶ 0064). Moreover, “the choke control 110 uses the choke’s flow coefficient (Cv) for tuning the control and determining the required adjustment to the current choke position” (¶ 0075) where the “choke position” is in terms of percent open between 0% and 100% (¶ 0077). Additionally, the surface backpressure is “measured upstream from the drilling chokes 22” (¶ 0037) disclosing “fluid pressure in the well before the choke.”)
“wherein during the determining the relationships in (b) and (c) operating fluid pumps at a constant rate and measuring pressure at a plurality of predetermined fractional choke openings” While Brana teaches fluid pumps and measuring pressure at a plurality of fractional choke openings (see above), Brana does not explicitly teach the pumps are “at a constant rate” and the plurality of fractional choke openings are “predetermined.”
Dietrich teaches “The simplistic calibration set-up is a pump that has a variable speed drive to create different flow rates measured by a flowmeter and a pressure transducer upstream of the choke assembly” (¶ 0083). Fig 7 depicts 3 different flow rates where the speed of the pump is constant for each of the different flow rates. Additionally, “While holding the flowrate Q constant (disclosing “operating the fluid pumps at a constant rate”) for each step, the choke is closed in small stepped increments until the pressure in the upstream side 32 of the central flow conduit (which may be measured using a pressure sensor connected to port 9) reaches pmax” (¶ 0086) discloses “measuring pressure at a plurality of predetermined fractional choke openings.”
It would have been obvious for one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the method for tuning a managed pressure drilling system as taught by Brana by including operating the pump at a constant rate and using predetermined fractional choke openings as taught by Dietrich to decouple the pump’s effect from the choke’s effect in order to provide a method that “creates an accurate continuous gain scheduling PID calibration table to which further gain scheduling can be added, if required, for the particular manages pressure drilling parameters at the wellsite” (Dietrich, ¶ 0080).
Brana teaches:
“directing the controlled output to an automatic choke to automatically control the fractional choke opening thereof in response to the control input” (Brana, Abstract, ¶ 0038-
¶ 0042: Brana teaches “the control system 100 can automatically detect, control, and circulate out such influxes by operating the chokes 22 on the choke manifold 20” (¶ 0039) where the “influxes” include a “kick” which occur “because the pressure exerted by the column of drilling fluid is not great enough to overcome the pressure exerted by the fluids in the formation being drilled” (¶ 0040).)
Brana does not teach:
“determining a relationship between (ii) a delay time of the first observable measured pressure response in the well after a change in the fractional choke opening.”
Hardt teaches:
“determining a relationship between (ii) a delay time of the first observable measured pressure response in the well after a change in the fractional choke opening” (Hardt, fig. 1, ¶ 0009-¶ 0010, ¶ 0016, ¶ 0021, ¶ 0024, ¶ 0030, ¶ 0037-¶ 0038: Hardt teaches “prioritizing of each of the responses of two or more pressure control components may be based on various operating variables including, for example, downhole drilling requirements, impact on rate of penetration, impact on bottom hole cleaning, and speed of response, i.e., length of time response takes to implement and length of time for response to affect bottom hole pressure, downhole drilling requirements, and magnitude of desired change in pressure” (¶ 0030) where “speed of response” discloses “delay time” and “prioritizing” “speed of response” discloses “determining a relationship between a delay time of measured pressure response in the well” as the “speed of response” is different for the different “pressure control components.” A “measuring device 127” is “for measuring a pressure downhole while drilling” (¶ 0021) and “pressure control components” include “control choke 136”(¶ 0026) which changes the choke opening. Moreover, the “PLC 152 may instruct a choke disposed in the choke manifold 136 to fully open in order to reduce pressure in the well bore 104” (¶ 0038) disclosing a “pressure response in the well after a change in fractional choke opening”).
It would have been obvious for one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the method for tuning a managed pressure drilling system as taught by Brana by including analyzing the pressure response time as taught by Hardt to provide a more thorough understanding of the pressure response in order to “improve efficiency and safety while drilling a well bore by effectively mitigating adverse fluid events” (Hardt, ¶ 0009).
Regarding Claim 2 Brana teaches:
“pumping fluid through a conduit extended into the well” (Brana, fig. 1, ¶ 0033-¶ 0034, ¶ 0048: Fig. 1 depicts mud pumps 50 and a drill string 14 disclosing “pumping fluids through a conduit extended into the well” as mud pumps pump fluid (¶ 0048) and the drill string is a conduit and is within the wellbore.)
“adjusting the fractional choke opening and changing a rate of the pumping fluid so that the measured fluid pressure remains constant” (Brana fig. 2B, ¶ 0050-¶ 0053: Brana teaches “controlling pressure during drilling essentially requires moving the chokes 22 with a control to achieve a necessary amount of pressure or flow according to the purposes of the well control operations governed by the control system” (¶ 0050). Opening the choke increases the fluid flow thereby decreasing pressure and closing the choke decreases the flow rate while increasing the pressure (see fig. 2B). Therefore “maintaining a predefined pressure” which involves “eliminating and minimizing pressure spikes and oscillations that might exceed the drilling window parameters” (¶ 0052) is achieved by using the PID (proportional-integral-derivative) control to control the chokes in order to adjust and stabilize wellbore pressure and flow (¶ 0053) where “maintaining a predefined pressure” discloses “the measured fluid pressure remains constant,” “moving the chokes” discloses “adjusting the fractional choke opening,” and adjusting flow discloses “changing the rate of the pumping fluid.”
Brana does not teach:
“measuring flow rate of fluid leaving the well through an annular space between the conduit and a wall of the well, measuring pressure of fluid in the well upstream of the choke,
Hardt teaches:
“pumping fluid through a conduit extended into the well, measuring flow rate of fluid leaving the well through an annular space between the conduit and a wall of the well, measuring pressure of fluid in the well upstream of the choke” (Hardt, fig 1, ¶ 0019: Fig. 1 depicts a flow meter 123 and a pressure transducer 126 where the flow meter 123 measures the flow rate of the return line 102 (¶ 0019) disclosing “measuring the flow rate of fluid leaving the well through an annular space between the conduit and a wall of the well” and the pressure transducer 126 measures the pressure of the fluids delivered to the choke therefore “upstream of the choke,” Therefore the combination of Brana and Hardt discloses the limitations “pumping fluid through a conduit extended into the well, measuring flow rate of fluid leaving the well through an annular space between the conduit and a wall of the well, measuring pressure of fluid in the well upstream of the choke, adjusting the fractional choke opening and changing a rate of the pumping fluid so that the measured fluid pressure remains constant.”)
It would have been obvious for one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the method for tuning a managed pressure drilling system as taught by Brana as modified by measuring flow rate and pressure as taught by Hardt in order to maintain efficient hole cleaning for wellbore stability, operational efficiency, and to provide safe and effective drilling operations.
Regarding Claim 3 Brana as modified does not teach:
“measuring fluid pressure in the well upstream of the choke and change in the measured fluid pressure upstream of the choke with respect to the change in the fractional choke opening while pumping fluid into the well at a constant rate.”
Hardt teaches:
“measuring fluid pressure in the well upstream of the choke, and change in the measured fluid pressure upstream of the choke with respect to the change in the fractional choke opening while pumping fluid into the well at a constant rate” (Hardt, fig. 1, ¶ 0016, ¶ 0021, ¶ 0038: Hardt teaches a “rig pump pumping drilling fluid into the drill string” (¶ 0010), a plurality of sensors including a “pressure transducer 126 for measuring a pressure of fluid exiting the marine riser 116” (¶ 0021) which is fluid delivered to the choke therefore “upstream of the choke” (¶ 0016, fig 1) disclosing “measuring fluid pressure in the well upstream of the choke.” The “PLC 152 may instruct a choke disposed in the choke manifold 136 to fully open in order to reduce pressure in the well bore 104” (¶ 0038) disclosing a “change in the measured fluid pressure with respect to change in the fractional choke opening.” Moreover, “a method in accordance with embodiments disclosed herein may include pumping 401 a drilling fluid at an initial pump rate through a drill string 112, while maintaining a first casing pressure and a first riser level” (¶ 0035) disclosing “pumping fluid into the well at a constant rate”).
It would have been obvious for one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the method for tuning a managed pressure drilling system by characterizing change is the flow rate of a fluid flow through the choke as taught by Brana as modified by including measuring pressure change upstream of the choke as taught by as taught by Hardt to provide a more complete picture of the managed pressure drilling system in order to provide a system with an improved “efficiency and safety while drilling a well bore by effectively mitigating adverse fluid events” (Hardt, ¶ 0009).
Regarding Claim 4 Brana as modified does not teach:
“measuring pressure in the well upstream of the choke with respect to time, and determining an elapsed time between change in the fractional choke opening and a change in the measured pressure while pumping fluid into the well at a substantially constant rate.”
Hardt teaches:
“measuring pressure in the well upstream of the choke with respect to time, and determining an elapsed time between change in the fractional choke opening and a change in the measured pressure while pumping fluid into the well at a substantially constant rate” (Hardt, ¶ 0021, ¶ 0030, ¶ 0038: Hardt teaches “measuring device 127 for measuring a pressure downhole while drilling” (¶ 0021), the “PLC 152 may instruct a choke disposed in the choke manifold 136 to fully open in order to reduce pressure in the well bore 104” (¶ 0038) disclosing a “change in the fractional choke opening,” and “speed of response, i.e., length of time response takes to implement and the length of time for response to affect bottom hole pressure” (¶ 0030) disclosing the “measuring pressure in the well upstream of the choke” must be “with respect to time” in order to determine the “speed of response.” Moreover, “a method in accordance with embodiments disclosed herein may include pumping 401 a drilling fluid at an initial pump rate through a drill string 112, while maintaining a first casing pressure and a first riser level” (¶ 0035) disclosing “pumping fluid into the well at a substantially constant rate”).
It would have been obvious for one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the method for tuning a managed pressure drilling system as taught by Brana as modified by including analyzing the pressure response time as taught by Hardt to provide a more thorough understanding of the pressure response in order to “improve efficiency and safety while drilling a well bore by effectively mitigating adverse fluid events” (Hardt, ¶ 0009).
Regarding claim 5 Brana as modified does not teach:
“operating a fluid pump at a predetermined rate, fully opening the choke, decreasing the fractional choke opening in predetermined steps, and measuring pressure drop across the choke.”
Dietrich teaches:
“operating a fluid pump at a predetermined rate, fully opening the choke, decreasing the fractional choke opening in predetermined steps, and measuring pressure drop across the choke” (Dietrich, fig. 7, ¶ 0083-¶ 0086: Dietrich teaches “The simplistic calibration set-up is a pump that has a variable speed drive to create different flow rates measured by a flowmeter and a pressure transducer upstream of the choke assembly” (¶ 0083) where “the desired flowrate calibration range is determined from 0 to Qmax, then divided into a predetermined number of flow rate steps (n)” (¶ 0085) disclosing “operating a fluid pump at a predetermined rate” as each different flowrate corresponds to a different pump speed. Fig 7 depicts 3 different flow rates where the speed of the pump is constant for each of the different flow rates. Additionally, “While holding the flowrate Q constant for each step, the choke is closed in small stepped increments until the pressure in the upstream side 32 of the central flow conduit (which may be measured using a pressure sensor connected to port 9) reaches pmax” (¶ 0086) discloses “decreasing the fractional choke opening in predetermined steps, and measuring pressure drop across the choke.” A person of ordinary skill in the art would understand a choke in the fully opened position would be the common starting point as the pressure would be at a minimum.)
It would have been obvious for one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the method for tuning a managed pressure drilling system as taught by Brana as modified by including operating the pump at a constant rate and using predetermined fractional choke openings as taught by Dietrich to decouple the pump’s effect from the choke’s effect in order to provide a method that “creates an accurate continuous gain scheduling PID calibration table to which further gain scheduling can be added, if required, for the particular manages pressure drilling parameters at the wellsite” (Dietrich, ¶ 0080).
Response to Arguments
Applicant’s arguments (remarks) filed on 12/15/2025 have been fully considered.
Regarding Claim Objections page 4 of Applicant’s remarks, based on Applicant’s arguments and changes made to the claims, the objections have been withdrawn.
Regarding Claim Rejections – 35 U.S.C. § 112 page 4-5 of Applicant’s remarks, based on Applicant’s arguments and changes made to the claims, the 35 USC 112(b) rejections have been withdrawn. Due to the amendments, new 35 USC 112(b) rejections have been written.
Regarding Claim Rejections – 35 U.S.C. 103 page 5-11 of Applicant’s remarks, Applicant argues “The Applicant has amended claim 1 to recite that the method comprises "determining a relationship between change in measured flow rate of fluid through the choke and a constant pressure drop across the choke." Brana, to the extent it discloses any form of characterization of choke opening with respect to flow rate at constant pressure drop clearly does not disclose determining the claimed relationship of measured flow rate at constant pressure drop with respect to choke opening on a managed pressure drilling system installed on a drilling unit. To the extent any such choke opening relationship is disclosed in Brana, it is either predetermined or laboratory determined. Accordingly, the foregoing determining a relationship is not disclosed in Brana.” (remarks, page 5-6).
Examiner respectfully disagrees. Brana teaches “Software components of the control system 100 then compare the flowrate in and out of the wellbore 16, the injection pressure (or standpipe pressure), the surface backpressure (measured upstream from the drilling chokes 22), the position of the chokes 22, and the mud density. Comparing these variables, the control system 100 identifies minute downhole influxes and losses on a real-time basis to manage the annulus pressure during drilling” (Brana, ¶ 0037) where “Comparing these variables” discloses “determining a relationship” between the “change in measured flow rate of fluid through the choke with respect to fractional choke opening at a constant pressure drop across the choke” and between “change in the measured fluid pressure in the well and change in the fractional choke opening at a constant fluid flow rate.” Brana uses the generic equation “
P
o
u
t
=
K
p
c
v
*
e
t
+
P
c
” , in determining the relationship between the above mentioned variables.
P
c
is the current choke position and
P
o
u
t
is the new choke position relative to the current choke position,
e
t
is the Instantaneous Error at time (t) (SP-PV) where SP is the pressure set point (or set point flow), and PV is the measured pressure (or measured flow) (¶ 0078-¶ 0079), and
K
p
c
v
=
C
V
*
g
*
e
i
where
K
p
c
v
is the correction factor,
C
V
is the flow coefficient,
g
is the gain, and
e
i
is the interpolated error factor (Brana, ¶ 0085-¶ 0095) to determine specific relationships using measured data such as (SP-PV), where SP is the pressure set point (or set point flow) and PV is the measured pressure (or measured flow), which changes as measured pressure or flow changes, and the correction factor,
K
p
c
v
, which is determined using a “spline interpolation based on the current choke position 120 relative to the choke’s flow coefficient
C
V
” (Brana, ¶ 0081) which changes as the choke’s position and flow coefficient change. (See Brana, fig 5 and fig 6A) thereby “determining a relationship” with respect to the above mentioned variables. Examiner respectfully suggests expressly reciting the type of change to narrow the claim language. Examiner respectfully suggests expressly reciting the type of relationship or how a relationship is determined in order to narrow the claim language.
Applicant argues “As explained with reference to the choke characterization explained above, claim 1 has been amended to recite "determining a relationship" between change in fluid pressure in the well and the change in the fractional choke opening at a constant fluid flow rate into the well. Brana does not disclose any such relationship determination. Further, the Office's reasoning is believed to be incorrect. It is true that a change in surface backpressure produces a corresponding change in bottom hole pressure. However the magnitude of this change, and the fluid pressure profile over the (axial length) depth of the well is influenced by many factors” (remarks, page 6)
Examiner respectfully disagrees. Brana teaches “Software components of the control system 100 then compare the flowrate in and out of the wellbore 16, the injection pressure (or standpipe pressure), the surface backpressure (measured upstream from the drilling chokes 22), the position of the chokes 22, and the mud density. Comparing these variables, the control system 100 identifies minute downhole influxes and losses on a real-time basis to manage the annulus pressure during drilling” (Brana, ¶ 0037) where “Comparing these variables” discloses “determining a relationship” between the “change in the measured fluid pressure in the well and change in the fractional choke opening at a constant fluid flow rate” (see above). Additionally, a “change in the measured fluid pressure in the well” is the claim language which Brana teaches. Examiner respectfully suggests expressly reciting the type of change to narrow the claim language.
Applicant argues “Additionally, Brana allegedly teaches maintaining a flow-in, flow-out equilibrium for a specified time, para. 0044) disclosing "a constant fluid flow rate into the well." The Applicant respectfully disagrees and points out that paragraph 0044 says, "once the flow-out and flow-in difference is brought under control, the control system 100 will maintain its equilibrium for a specified time before switching to the next mode", bringing the difference under control does not necessarily mean a constant fluid flow rate, it might well be that more fluid is pumped down to account for losses, or less fluid to account for influx control” (remarks page 6).
Examiner respectfully disagrees. Brana teaches “Once the flow-out and flow-in difference is brought under control, the control system 100 will maintain this equilibrium for a specified time before switching to the next mode” (Brana, ¶ 0044) where, in the paragraph above, Brana explains the “difference is brought under control” while the “stand pipe pressure will be maintained constant by automatically adjusting the surface backpressure. . .” (Brana, ¶ 0043) where if the stand pipe pressure is constant, the “fluid flow rate into the well” will also be constant.
Applicant argues “As previously stated, "characterizing" in claim 1 has been amended in every instance to "determining a relationship" which is simply not disclosed by Brana. Further, the allegedly disclosed response time is an entirely different response time. In claim 1, the response time of the well means the difference between a setpoint change and a first observable measurable pressure reaction from the well. In Brana, the time is disclosed as being between a setpoint change, and the well pressure to reach the new that new setpoint. To the extent the Office takes the position that "response time" reads on the time parameter disclosed in Brana, the Applicant respectfully points out that Brana does not disclose the claimed determining a relationship” (remarks, page 7).
Examiner respectfully disagrees. Fig. 7B depicts a response curve 152 using a standard PID control (¶ 0102) and a response curve 155 where the “test was conducted using a fixture that provided a flow of fluid with an actuator to control a choke valve to adjust and maintain pressure” (Brana, ¶ 0101) which discloses “changes in the fractional choke opening.” The response curve in fig. 7B depicts a comparison of response curves in two different systems where the choke control increase 156 of curve 155 is more rapid (response time) reaching and maintaining the set point of 140 psi from 70 psi (¶ 0104) and the decrease 157 is smoother and more rapid (response time) than the response times of curve 152. The response time curves disclose “determining a relationship between a response time of measured pressure and changes in the fractional choke opening.” Therefore Brana reads on the claim language.
Applicant argues “The Applicant believes that this is an incorrect statement. Characterizations are not the same as maintaining a certain backpressure. Characterizations (determining a relationship) are static measurements with a fixed choke position, and a stabilized system, maintaining a surface back pressure will involve continuously changing choke positions, it is a dynamic process. Characterization (determining the relationships) is used to calculate the correct control parameters to allow for an efficient backpressure control” (remarks, page 7).
Examiner respectfully disagrees. Brana teaches “the disclosed choke control 110 can use the error between measure pressure and pressure set point to adjust the choke position (e.g., open the chokes) to handle the loss and maintain the surface back pressure within the desired drilling window” (Brana, ¶ 0107) teaching changes in the choke position results from changes in the measured pressure and are used to adjust and maintain the surface back pressure thereby teaching a “determining a relationship between a surface back pressure applied to the well and the fractional choke opening.” Examiner respectfully suggests expressly reciting the type of relationship or how a relationship is determined in order to narrow the claim language.
Applicant argues “The Applicant respectfully disagrees. For any MPD control system to work properly the pressure before the choke has to be measured, this is the "surface back pressure". However, the "surface back pressure" is distinct from the "pressure in the well". The pressure in the well is influenced by many factors and varies across the well depth, fluid composition across the well, surface back pressure, bit characteristics, etc” (remarks page 8).
Examiner respectfully disagrees. Brana teaches the surface backpressure is “measured upstream from the drilling chokes 22” (¶ 0037) disclosing “fluid pressure in the well before the choke.” As can be seen, claim language states, “fluid pressure in the well before the choke” and Applicant agrees that the surface back pressure is a fluid pressure measured before the choke therefore Brana discloses the claim language. Additionally, stated in MPEP 2111.01 II “Though understanding the claim language may be aided by explanation contained in the written description, it is important not to import into claim limitations that are not part of the claim” (1st paragraph). “Well pressure” is not part of the claim language.
Applicant argues “The Applicant respectfully disagrees. Dietrich, para. 0076 teaches "In situ calibration methods of the PID controller can be difficult. Part of the problem is the widely varying range of pressures and flowrates that can be encountered in a typical drilling operation". Dietrich para. 0082 teaches also "The advantage of such a solution is that we have a completely known and calibrated "choke system" which when installed at the drilling location can have further gain adjustments incorporated that are specific to the drilling conditions like the drilling fluid compressibility, the well bore volume and therefore inherent wellbore storage characteristics ".
Therefore the solutions as described in Dietrich are offsite, use different equipment and are specifically geared towards determining equipment characteristics, as with Brana and Hardt. This patent describes a method of "further gain adjustments" to incorporate specific drilling/well conditions. None of the references describes a method to characterize these well conditions, apart from mentioning that "attempt to do on-site calibrations of the PID controller but this is less than satisfactory", Dieterich 0082. It would be clear for a person skilled in the art that the methods described in the prior art do not work, otherwise those would have mentioned as such]” (remarks, page 8-9).
Examiner respectfully disagrees. Dietrich is used only to teach “operating the fluid pumps at a constant rate” and “measuring pressure at a plurality of predetermined fractional choke openings.”
Applicant argues “The Applicant respectfully disagrees. Hardt 0009 does not mention characterization of measured pressure response, para. 0010 does not mention characterization of measured pressure response, para. 0016 only describes the use of a choke manifold as back pressure device; there is no mention of fractional choke openings or of delay times, paras. 0024, 0037 and 0038 do not mention characterization of measured pressure response, wherein as explained above, "characterizing" has been amended to read "determining a relationship." (remarks, page 9).
Examiner respectfully disagrees. Hardt teaches “prioritizing of each of the responses of two or more pressure control components may be based on various operating variables including, for example, downhole drilling requirements, impact on rate of penetration, impact on bottom hole cleaning, and speed of response, i.e., length of time response takes to implement and length of time for response to affect bottom hole pressure, downhole drilling requirements, and magnitude of desired change in pressure” (¶ 0030) thereby prioritizing “speed of response” discloses “determining a relationship between a delay time of measured pressure response in the well” as the “speed of response” is different for the different “pressure control components.”
Applicant argues “The Applicant respectfully disagrees. The "delay" disclosed in Hardt is not the reaction time of the well, but is the reaction time of surface (or controlling devices) and is not related at all to the well. Hardt specifically mentions "responses of two or more pressure control components ". There needs to be more than one component, otherwise the method as described in Hardt does not work. Reference Hardt para. 0034 for examples "decreasing a pump rate of a rig pump 132, increasing a pump rate of the riser pump 138, opening a choke disposed in the choke manifold 136, and or decreasing a weight of the drilling fluid pumped down hole 104 with the mixing tank system" It is clear for persons skilled in the art that opening a choke has a faster response compared to changing pump rates of changing the weight of the drilling fluid. This is the delay time mentioned in Hardt - and not the well pressure response delay time recited in claim 1 (which is based on well characteristics and not equipment specifics)” and “The Applicant respectfully disagrees. Pressure response time as taught by Hardt is pressure response time of equipment and not the well. A person skilled in the art would recognize changing the mud weight will take a long time (long response time) compared to changing a choke opening (short response time). The method as claimed aims to quantify the well characteristics to properly tune choke controllers where Hardt would provide no ability correct the choke operating parameters for changes in well conditions (as contrasted with equipment conditions)” (remarks, page 10).
Examiner respectfully disagrees. Brana teaches a “speed of response” such as “length of time for response to affect bottom hole pressure” (¶ 0030) disclosing a “delay time of the first observable measured pressure response in the well” where the response is due to a change in choke opening by the control choke (¶ 0026).
Regarding dependent claims 2-5, the above answers are sufficient to respond to the Applicant’s arguments.
Conclusion
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. Dillard et al., U.S. Pub. No. 2017/0328151 A1, teaches using a choke to set the flow value to a calculated flow value based on the flow coefficient value and a pressure differential measured across the choke.
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/DENISE R KARAVIAS/Examiner, Art Unit 2857
/MICHAEL J DALBO/Primary Examiner, Art Unit 2857