Prosecution Insights
Last updated: April 19, 2026
Application No. 18/562,792

METHOD FOR MULTISTAGE FRACTURING OF A GEOTHERMAL WELL

Non-Final OA §102§103
Filed
Nov 20, 2023
Examiner
WALLACE, KIPP CHARLES
Art Unit
3674
Tech Center
3600 — Transportation & Electronic Commerce
Assignee
Ncs Multistage LLC
OA Round
1 (Non-Final)
78%
Grant Probability
Favorable
1-2
OA Rounds
2y 10m
To Grant
99%
With Interview

Examiner Intelligence

Grants 78% — above average
78%
Career Allow Rate
717 granted / 914 resolved
+26.4% vs TC avg
Strong +25% interview lift
Without
With
+25.2%
Interview Lift
resolved cases with interview
Typical timeline
2y 10m
Avg Prosecution
24 currently pending
Career history
938
Total Applications
across all art units

Statute-Specific Performance

§101
0.6%
-39.4% vs TC avg
§103
54.0%
+14.0% vs TC avg
§102
29.2%
-10.8% vs TC avg
§112
11.5%
-28.5% vs TC avg
Black line = Tech Center average estimate • Based on career data from 914 resolved cases

Office Action

§102 §103
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 . Claim Rejections - 35 USC § 102 The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action: A person shall be entitled to a patent unless – (a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention. Claim(s) 25-27 is/are rejected under 35 U.S.C. 102a1 as being anticipated by Kruger (US 20170321934 A1). With respect to claim 25, Kruger discloses a method of stimulating a formation to facilitate geothermal heat harvesting comprising: providing a conduit (4) within a well (3), the conduit comprising a series of valves (combination 7, 61, figs. 3, 9), each valve having one or more ports (7) which are openable to allow fluid flow through a wall of the conduit; performing the following steps for one or more valve of the series of valves: selectively opening a valve of the series of valves (pgph. 81); injecting a treatment fluid through the open valve into the formation to open and fill fractures within the formation (pgphs. 81, 82), wherein the treatment fluid comprises a thermally conductive granular solid (proppants are granular solids that conduct heat to some degree); and sealing the open valve to prevent further fluid communication between the formation and the conduit via the sealed valve (pgph. 79); unsealing the valves (pgphs. 79, 81) to permit fluid flow between the conduit and the formation; and circulating a working fluid within the conduit and the fractures to harvest heat from the formation (pgph. 82). With respect to claims 26 and 27, Kruger further discloses wherein the method comprises providing a thermally conductive granular solid within an annulus between the conduit and the well (pgph. 82) wherein the method comprises providing a second conduit (9) within a second well (8), wherein both conduits are in fluid communication with each other through the formation, wherein circulating the working fluid comprises injecting the working fluid into one of the conduits and recovering the working fluid at the other conduit (pgph. 82). Claim Rejections - 35 USC § 103 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. Claim(s) 1, 2, 4, 7-12, 14, 17-21, 23, and 24 is/are rejected under 35 U.S.C. 103 as being unpatentable over Kruger (US 20170321934 A1) in light of Nevison (US 20200191444 A1), hereinafter Nev. With respect to claim 1, Kruger discloses a method of stimulating a formation to facilitate geothermal heat harvesting comprising: providing a conduit (4) within a well, the conduit comprising a series of valves (combination 7, 61, pgph. 79), each valve having one or more ports (7) which are openable to allow fluid flow through a wall of the conduit; performing the following steps for one or more valve of the series of valves, to create system within the well: selectively opening a valve of the series of valves (pgph. 81); injecting a treatment fluid through the open valve into the formation to open and fill fractures within the formation (pgphs. 81, 82); and sealing the open valve to prevent further fluid communication between the formation and the conduit via the sealed valve (pgph. 79); However, Kruger does not disclose forming a closed-loop system and therefore does not disclose circulating the fluid with all the valves closed. Nevertheless, Nev discloses fracturing a geothermal wellbore in a closed-loop system and circulating fluid through the conduit with communication between the conduit and the formation sealed off (pgphs. 3, 9, 28, 52, 53, 64). Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date to have converted the wellbore of Kruger to a closed-loop system in order to reduce contamination of the heat transfer fluid and to reduce environmental impact of a geothermal system as taught by Nev (pgph. 3), this conversion would entail closing of the valves of Kruger after fracturing and propping in order to produce the closed system as taught by Nev (pgphs. 9, 53) and placement of a tubing (such as 530 of Nev) into the conduit of Kruger and circulation of the working fluid with the valves closed (necessary for hydraulic isolation) as taught by Nev (pgph. 64). With respect to claim 2, Kruger further discloses wherein the sealing of the open valve comprises closing the ports of the valve by shifting a sliding sleeve to directly block the ports (pgph. 79). With respect to claim 4, Kruger further discloses wherein each of the valves is configured to be selectively opened by a shifting tool or other object into the well which impinges on, and moves, one or more components of the valve to be opened (pgph. 79). With respect to claim 7, Nev discloses wherein the treatment fluid has a thermal conductivity of more than 0.6 W/m.K (pgphs. 108-110). With respect to claim 8, Nev discloses wherein the treatment fluid comprises one or more of: tin, Beryllium Oxide (pgph. 109). With respect to claim 9, Nev discloses wherein the treatment fluid consists of non-aqueous materials (pgph. 106). With respect to claims 10-12, Nev discloses wherein the treatment fluid comprises thermally conductive proppant in a carrier fluid, the thermally conductive proppant being formed of a material with a thermal conductivity of at least 10 W/m.K, wherein the treatment fluid comprises one or more of: conductive nano particles, thermally conductive powder, thermally conductive beads; thermally conductive ceramics, thermally conductive elements, a metal, alumina, aluminum, and graphite (pgph. 107, 109). With respect to claims 14, Nev discloses wherein the formation is a dry formation (pgph. 108, 104). With respect to claims 17 and 18 Nev discloses wherein a thermally conductive fluid is injected between the conduit and formation prior to stimulating the formation, wherein the thermally conductive fluid has a different composition then the treatment fluid (pgph. 103). With respect to claim 19, Kruger in light of Nev discloses wherein the valves are sealed, and a working fluid is injected into the conduit in a closed-loop configuration to harvest heat from the formation and return it to surface without directly contacting the formation (discussed supra). With respect to claims 20, Nev discloses wherein the treatment fluid is a fracturing fluid configured to create fractures in the formation when injected into the formation under pressure (pgphs. 108-110). With respect to claims 21, Nev discloses wherein the treatment fluid comprises an acid configured to grow fractures within the formation by dissolving portions of rock (pgph. 103). The limitations of claims 23 and 24 are substantially similar to those of previously rejected claims 1, 2, 4, and 10-12. Claim(s) 3 is/are rejected under 35 U.S.C. 103 as being unpatentable over Kruger and Nev as applied to claim 1 above, and further in view of Ayasse (US 20170226834 A1), hereinafter Ay. With respect to claim 3, Kruger and Nev fails to disclose the blocking by seating as claimed. Nevertheless, Ay discloses using ball-actuated sleeves where a ball (sealing member) seats on a sleeve (thereby blocking the conduit between the valve and the surface) and slides it closed (pgph. 61) Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date to have used a ball to close the sleeves of Kruger as taught by Ay since this is the application of a known technique in a similar device to improve it in the same way with predictable and obvious results and a reasonable expectation for success. Claim(s) 5 is/are rejected under 35 U.S.C. 103 as being unpatentable over Kruger and Nev as applied to claim 1 above, and further in view of Perkins (US 4705113 A). With respect to claim 5, Kruger and Nev fails to disclose the circulating. Nevertheless, Perkins discloses circulating several well volumes of a cooling fluid to cool the well prior to injecting the treatment fluid at pressures sufficient to fracture the formation (col. 3 l. 45 – col. 4 l. 48). Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date to have circulated cooling fluid in Kruger prior to fracturing in order to reduce the required fracturing pressure as taught by Perkins (col. 2 ll. 23-37). Claim(s) 6 is/are rejected under 35 U.S.C. 103 as being unpatentable over Kruger and Nev as applied to claim 1 above, and further in view of Agashe (US 20170240801 A1), hereinafter Ag. With respect to claim 6, Kruger and Nev fails to disclose the use of a salt as claimed. Nevertheless, Ag discloses the use of a salt (ammonium chloride, pgph. 39) which is configured to be molten at downhole temperatures and pressures (it is capable of melting at temperatures commonly reached on downhole geothermal wells). Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date to have used a fracturing fluid containing in Kruger in order to help the surfactant maintain micelle entanglement as taught by Ag (pgph. 25). Claim(s) 13 and 15 is/are rejected under 35 U.S.C. 103 as being unpatentable over Kruger and Nev as applied to claim 1 above, and further in view of Gill (US 20170260442 A1). With respect to claim 3, Kruger and Nev fails to disclose the use of a material configured to melt downhole. Nevertheless, Gill discloses that it is common for geothermal wells to be around or above 300 degrees C (pgph. 6), and Nev discloses the use of tin as a granular particle in the treatment fluid (pgph. 109). Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date to have provided the well system of Kruger in light of Nev in a formation which reached 300 degrees or more since this is the application of a known technique in a similar device to improve it in the same way with predictable and obvious results and a reasonable expectation for success and to have used tin in the treatment fluid (which will melt at these temperatures) in order to increase conductivity as taught by Nev (pgph. 109). With respect to claim 14, Gill discloses this (pgph. 6). Claim(s) 16 is/are rejected under 35 U.S.C. 103 as being unpatentable over Kruger and Nev as applied to claim 1 above, and further in view of Leggett (US 20150204993 A1). With respect to claim 16, Kruger and Nev fails to disclose the pressure claimed. Nevertheless, Leggett discloses that it is common for geothermal wells to be around or above 30MPa (pgph. 41) Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date to have provided the well system of Kruger in light of Nev in a formation with a temperature at or above 26MPa as taught by Leggett (pgph. 41) since this is the application of a known technique in a similar device to improve it in the same way with predictable and obvious results and a reasonable expectation for success. Claim(s) 22 is/are rejected under 35 U.S.C. 103 as being unpatentable over Kruger in light of Patel (US 20210381340 A1). With respect to claim 22, Kruger discloses an apparatus for stimulating a formation to facilitate geothermal heat harvesting comprising: a conduit, the conduit having a series of valves along its length, each valve having ports which are openable and sealable in sequence to control fluid flow through the wall, wherein in a sealed configuration, each port is sealed (discussed supra). However, Kruger fails to disclose the use of metal-to-metal seals for the sleeve 61. Nevertheless, Patel discloses a sleeve which uses metal seals to seal a port (pgph. 39). Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date to have used the sealing configuration of Patel with the sleeve of Kruger in order to provide a system which seals at lower pressures while preventing blowouts as taught by Patel (pgph. 39). Conclusion The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. US 20150300327 A1 also discloses fracturing in a geothermal well, as does US 20210396430 A1 who uses tin which melts to increase conductivity. Any inquiry concerning this communication or earlier communications from the examiner should be directed to KIPP CHARLES WALLACE whose telephone number is (571)270-1162. The examiner can normally be reached Monday - Friday 12:00 PM - 8:00 PM. Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice. If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Doug Hutton can be reached at (571) 272-4137. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300. Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000. /KIPP C WALLACE/Primary Examiner, Art Unit 3674 10/08/2025
Read full office action

Prosecution Timeline

Nov 20, 2023
Application Filed
Oct 08, 2025
Non-Final Rejection — §102, §103 (current)

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Study what changed to get past this examiner. Based on 5 most recent grants.

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Prosecution Projections

1-2
Expected OA Rounds
78%
Grant Probability
99%
With Interview (+25.2%)
2y 10m
Median Time to Grant
Low
PTA Risk
Based on 914 resolved cases by this examiner. Grant probability derived from career allow rate.

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