Prosecution Insights
Last updated: April 18, 2026
Application No. 19/197,226

CEMENT SYSTEM FOR CO2 INJECTION AND SEQUESTRATION IN MAFIC/ULTRAMAFIC ROCK AND METHOD OF USE

Non-Final OA §103§112
Filed
May 02, 2025
Examiner
LEE, CRYSTAL J
Art Unit
3674
Tech Center
3600 — Transportation & Electronic Commerce
Assignee
Protostar Group Ltd.
OA Round
1 (Non-Final)
82%
Grant Probability
Favorable
1-2
OA Rounds
2y 3m
To Grant
99%
With Interview

Examiner Intelligence

Grants 82% — above average
82%
Career Allow Rate
415 granted / 506 resolved
+30.0% vs TC avg
Strong +22% interview lift
Without
With
+21.9%
Interview Lift
resolved cases with interview
Typical timeline
2y 3m
Avg Prosecution
20 currently pending
Career history
526
Total Applications
across all art units

Statute-Specific Performance

§101
1.8%
-38.2% vs TC avg
§103
49.3%
+9.3% vs TC avg
§102
15.7%
-24.3% vs TC avg
§112
28.6%
-11.4% vs TC avg
Black line = Tech Center average estimate • Based on career data from 506 resolved cases

Office Action

§103 §112
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 . Election/Restrictions Applicant's election with traverse of Group I (Claims 1-12) in the reply filed on December 24, 2025 is acknowledged. The traversal is on the ground(s) that “The Office has simply stated the conclusion. The burden is on the Office to provide an example of the alleged assertion by the Office. Yet, the Office has provided no examples or evidence of record to support the conclusion. Accordingly, the Office has failed to meet the burden necessary in order to sustain the Restriction Requirement.” (See Applicant’s Remarks, filed 12/24/2025: p. 5). This is not found persuasive, because the cementing method of Group I does not require many of the structural wellbore system components or engineering specifications of Group II and/or Group III. The Examiner maintains that the process as claimed can be practiced by another materially different apparatus. Restriction for examination purposes is proper, because the inventions are independent or distinct for the reasons given above and there would be a serious search and/or examination burden if restriction were not required because one or more of the following reasons apply: the inventions have acquired a separate status in the art due to their recognized divergent subject matter; and the inventions require a different field of search (e.g., searching different classes/subclasses or electronic resources, or employing different search strategies or search queries). The requirement is still deemed proper and is therefore made FINAL. Claims 13-20 are withdrawn from further consideration pursuant to 37 CFR 1.142(b), as being drawn to a nonelected invention, there being no allowable generic or linking claim. Applicant's election with traverse of Species A and Species B in the reply filed on December 24, 2025 is acknowledged. The traversal is on the ground(s) that “Applicants make no statement regarding the patentable distinctness of the species, but note that for restriction to be proper, there must be a patentable difference between the species as claimed. MPEP § 808.01(a). The burden is on the Examiner to provide reasons and/or examples to support any conclusion in regard to patentable distinction. MPEP § 803. Applicants respectfully submit that the Office has failed to provide reasons and/or examples to support the assertion that the species "are independent or distinct because as disclosed, the different species have mutually exclusive characteristics for each identified species. In addition, these species are not obvious variants of each other based on the current record" as alleged by the Office. The Office has simply stated a conclusion. The Office has not provided any reasons or examples to support a conclusion that the species are indeed patentably distinct.” (See Applicant’s Remarks, filed 12/24/2025: p. 5). This is not found persuasive, because the species are independent or distinct because as disclosed, the different species have mutually exclusive characteristics for each identified species. In addition, these species are not obvious variants of each other based on the current record. For example, a cement retarder does not have the same chemical properties as an extender, and each species behaves differently within a cement composition. Additionally, synthetic or man/made materials do not have the same chemical structures and/or properties as bio-based materials, and each species may behave differently within a cement composition. The requirement is still deemed proper and is therefore made FINAL. Claim 4 is withdrawn from further consideration pursuant to 37 CFR 1.142(b), as being drawn to a nonelected species, there being no allowable generic or linking claim. Specification The abstract of the disclosure is objected to, because there is typographical error in line 1. A corrected abstract of the disclosure is required and must be presented on a separate sheet, apart from any other text. See MPEP § 608.01(b). Claim Objections Claim 6 is objected to because of the following informalities: improper spacing between limitations. Appropriate correction is required. Claim Rejections - 35 USC § 112(b) 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. Claims 1-3 and 5-20 are rejected under 35 U.S.C. 112(b) 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. Claim 1 recites the limitation “according to ASTM C109 standard” in line 15. There appears to be no indication of the date to which the standard is considered and/or applied within the original disclosure. Because ASTM standards change over time, it is unclear as to what version of the standard the Applicant intends to use and/or claim. Claim 6 is rejected under 35 U.S.C. 112(b) 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. Claim 6 recites the limitation "the mixture of the aromatic alcohol and the plurality of amines, and the 1,4-butanediol diglycidyl ether" in lines 5-6. There is insufficient antecedent basis for this limitation in the claim. The Examiner suggests the following amendment to Claim 6: 6. (Currently Amended) The method of claim [[1]] 5, further comprising making the cementitious slurry mixture by: forming a cement slurry by first mixing the additives with water, followed by mixing the class G cement, the fly ash and the microsilica; forming an epoxy resin blend by mixing in an order of the bisphenol A-based diglycidyl ether; the mixture of the aromatic alcohol and the plurality of amines, and the 1,4-butanediol diglycidyl ether; mixing the cement slurry with the epoxy resin blend for up to 10 minutes to form the cementitious slurry mixture. 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. Claims 1-3 and 7-12 are rejected under 35 U.S.C. 103 as being unpatentable over Lewis et al. (US 2024/0093080) in view of Ellenberger et al. (US 5,252,636). Claim 1. A method of cementing a CO2 injection well bored in an underground geological formation formed of mafic and/or ultramafic rock, comprising: injecting a cementitious slurry mixture into an annulus between a well casing and an injection well wall, wherein the cementitious slurry mixture comprises: 60-80 wt.% of a class G cement; 10-35 wt.% of a fly ash; 1-5 wt.% of a microsilica; 1-5 wt.% of a plurality of additives; 10-15 wt.% of an epoxy resin blend, wherein wt% is based on the total weight of the class G cement, the fly ash, the microsilica, the additives and the epoxy resin blend, and curing the cementitious slurry mixture to form a cured cement, wherein the cured cement has a bonding strength of 350 to 400 bar after 7 days of curing according to ASTM C109 standard and a durability with a strength retention of at least 97% after up to 7 days exposure to CO2 containing fluid. Lewis discloses introducing a resin modified cement slurry (220) into a wellbore (305) penetrating a subterranean formation (300) containing a carbon dioxide injection zone (330); wherein the resin modified cement slurry may be introduced into a wellbore annulus (314) formed between the casing (312) and the walls (306) of the wellbore (305) and/or the casing (308) (Fig. 3; [0026]; [0080] – [0083]); wherein the resin modified cement slurry comprises: a hydraulic cement, such as a Portland cement classified as Class A, B, C, D, E, F, G, H, K and L cements in an amount of from about 20% to about 99% by weight of the resin modified cement slurry ([0026]; [0027]); a resin, such as an epoxy-based resin in an amount of from about 1% to about 60% by weight of the resin modified cement slurry ([0026]; [0028]); a hardener ([0026]; [0030]); and water ([0026]; [0047]). Lewis discloses that the resin modified cement slurry may further comprise: supplementary cementitious materials, such as fly ash ([0048]; [0049]) and silica fume ([0048]; [0053]); and other suitable additives in an amount from about 0.01% to about 5% by weight of the cementitious materials ([0057]). Lewis further discloses that the resin modified cement slurry may develop a 24-hour compressive strength in the range of from about 50 psi to about 10,000 psi (Examiner note: ≈ 3.45 bar to 689.48 bar). Lewis discloses that the resin modified cement slurry may further comprise: supplementary cementitious materials, such as fly ash ([0048]; [0049]) and silica fume ([0048]; [0053]), but Lewis does not expressly disclose 10-35 wt.% of a fly ash; and 1-5 wt.% of a microsilica. However, it has been held that “where the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation.” In re Aller, 220 F. 2d 454, 456, 105 USPQ 233, 235 (CCPA 1955). Moreover, Ellenberger teaches a cement composition containing the following dry mixture: cement; 2-25% by weight of a reactive resin; 2-25% by weight of a hardener; 0-50% by weight of silica fume; 10-150% by weight of fly ash; 50-500% by weight of aggregate; 0.5-10% by weight of admixtures; and 0-10% by weight of other additives (Col. 3, lines 5-14; Claim 6); wherein the cement composition may include any type of cement, including Portland cement (Col. 2, lines 37-64); and wherein the additives may comprise adhesion improving agents, defoaming agents, corrosion inhibitors, dispersing agents, gas eliminating agents, plasticizers, superplasticizers, air entraining agents, accelerators, retarders (Col. 2, line 65 – Col. 3, line 4; Claim 9). It would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to modify the resin modified cement slurry in Lewis with the concentration range(s) of silica and fly ash, as taught by Ellenberger, in order to optimize rheological properties of the cement slurry. Claim 2. Lewis discloses wherein the resin modified cement slurry comprises: a hydraulic cement, such as a Portland cement classified as Class G cement in an amount of from about 20% to about 99% by weight of the resin modified cement slurry ([0026]; [0027]); a resin, such as an epoxy-based resin ([0026]; [0028]); a hardener ([0026]; [0030]); and water ([0026]; [0047]). Lewis discloses that the resin modified cement slurry may further comprise: supplementary cementitious materials, such as fly ash ([0048]; [0049]) and silica fume ([0048]; [0053]); and other suitable additives in an amount from about 0.01% to about 5% by weight of the cementitious materials ([0057]). It would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to modify the compositional concentration ranges of the cement, fly ash, and silica fume within the resin modified cement slurry in Lewis to the concentration range(s) as claimed, because it has been held that “where the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation.” In re Aller, 220 F. 2d 454, 456, 105 USPQ 233, 235 (CCPA 1955). Claim 3. Lewis discloses that the resin modified cement slurry may include various additives, including: supplementary cementitious components, hydraulic binders, micronized solids, inert solid particulates or microparticles, hollow microspheres, elastic beads, weighting agents, lightweight additives (i.e. extenders), gas-generating additives, mechanical-property-enhancing additives, lost-circulation materials, filtration-control additives, fluid-loss-control additives, defoaming agents, foaming agents, thixotropic additive, dispersants, retarders, and/or accelerators in an amount from about 0.01% to about 5% by weight of the cementitious materials ([0057]; [0107]). It would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to modify the concentration ranges of the additives of the resin modified cement slurry in Lewis to the concentration range(s) as claimed, because it has been held that “where the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation.” In re Aller, 220 F. 2d 454, 456, 105 USPQ 233, 235 (CCPA 1955). Claim 4. (Withdrawn) Lewis discloses that the resin modified cement slurry may include various additives, including celluloses ([0057]; [0059]). Claim 7. Lewis discloses injecting the resin modified cement slurry at a sufficient pressure into the wellbore ([0087]); then injecting carbon dioxide at a sufficient pressure to cause the carbon dioxide to penetrate the carbon dioxide injection zone ([0089]). It would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to modify the injection pressure ranges of the resin modified cement slurry and carbon dioxide injection(s) in Lewis to the pressure range(s) as claimed, because it has been held that “where the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation.” In re Aller, 220 F. 2d 454, 456, 105 USPQ 233, 235 (CCPA 1955). Claim 8. Lewis discloses an uncemented portion of the well (Fig. 5). Claim 9. Lewis discloses selecting the resin based on the desired curing temperature ([0028]) and bottomhole static temperature ([0029]). Lewis discloses the resin modified cement slurries may develop a 24-hour compressive strength in the range of from about 50 psi (344 kPa) to about 10000 psi (68947 kPa) at a temperature ranging from 100°F (37.7°C) to 200°F (93.3°C) ([0063]). It would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to optimize the curing conditions of the resin modified cement slurry and carbon dioxide injection(s) in Lewis to the range as claimed, because it has been held that “where the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation.” In re Aller, 220 F. 2d 454, 456, 105 USPQ 233, 235 (CCPA 1955). Claim 10. Lewis discloses that the resin modified cement has an improved resistance to carbonation ([0064]). Since Lewis discloses the same composition as claimed, the resin modified cement would inherently act in the same manner as claimed, (i.e., it would be capable of a higher bonding strength, compressive strength and corrosion resistance). If there is any difference between the composition of Lewis and that of the instant claims, the difference would have been minor and obvious insofar as because it has been held that “products of identical chemical composition cannot have mutually exclusive properties.” A chemical composition and its properties are inseparable. Therefore, if the prior art teaches the identical chemical structure, the properties Applicant discloses and/or claims are necessarily present. See MPEP 2112.01(I), In re Best, 562 F2d at 1255, 195 USPQ at 433, Titanium Metals Corp v Banner, 778 F2d 775,227 USPQ 773 (Fed Cir 1985), In re Ludtke, 441 F2d 660, 169 USPQ 563 (CCPA 1971) and Northam Warren Corp v D F Newfield Co, 7 F Supp 773, 22 USPQ 313 (EDNY 1934). Claim 11. Lewis discloses injecting the resin modified cement slurry at a sufficient pressure into the wellbore ([0087]); then injecting carbon dioxide and/or carbonic acid in the presence of metered or formation water ([0065] – [0066]; [0089]). Claim 12. Lewis does not disclose reacting CO2 in the CO2-containing fluid with the mafic and/or ultramafic rock in the underground geological formation, wherein the mafic and/or ultramafic rock contains olivine and pyroxene, and has a density of 2.5 to 3.4 g/cm3. However, Lewis does disclose that carbonic acid may form as a result of injected or naturally present CO2 gas coming into contact with any of free water in the formation ([0066]), which the Examiner deems as a reaction. It would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to inject the resin modified cement slurry in Lewis into the claimed geological formation as an obvious matter of design choice based on choosing from a finite number of identified, predictable solutions, with a reasonable expectation of success. KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398, 415-421, 82 USPQ2d 1385, 1395-97 (2007). Claims 5-6 are rejected under 35 U.S.C. 103 as being unpatentable over Lewis et al. (US 2024/0093080) in view of Ellenberger et al. (US 5,252,636), further in view of Al-Yami et al. (US 2020/0071593). Claim 5. Lewis discloses that the resin modified cement slurry includes resin ([0026]), such as bisphenol A diglycidyl ether resins ([0028]); and a diamine hardener ([0026]; [0030]). However, Lewis does not disclose every component of the claimed epoxy resin blend. Al-Yami teaches a composition for sealing an annulus of a wellbore, the composition comprising an epoxy resin system, the epoxy resin system comprising: bisphenol-A-based epoxy resins ([0030]); a reactive diluent, such as butanediol diglycidyl ether ([0037]); a curing agent, such as diamine and/or aminoethylpiperazine ([0044] – [0045]); an accelerator, such as benzyl alcohol ([0050]). It would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to modify the resin in Lewis with the epoxy resin system, as taught by Al-Yami, in order to form an improved barrier to prevent fluids, such as gases, liquids, or both, from penetrating through the annulus ([0009]). Claim 6. It would have been on obvious matter of design choice to one of ordinary skill in the art, before the effective filing date of the claimed invention, to optimize the order of mixing based on choosing from a finite number of identified, predictable solutions, with a reasonable expectation of success. KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398, 415-421, 82 USPQ2d 1385, 1395-97 (2007). Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to Crystal J. Lee whose telephone number is (571)272-6242. The examiner can normally be reached M-F from 8:00am - 5:00pm. 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. /CRYSTAL J LEE/Primary Examiner, Art Unit 3674
Read full office action

Prosecution Timeline

May 02, 2025
Application Filed
Feb 03, 2026
Non-Final Rejection — §103, §112
Mar 26, 2026
Examiner Interview Summary
Mar 26, 2026
Applicant Interview (Telephonic)
Apr 02, 2026
Response Filed

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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
82%
Grant Probability
99%
With Interview (+21.9%)
2y 3m
Median Time to Grant
Low
PTA Risk
Based on 506 resolved cases by this examiner. Grant probability derived from career allow rate.

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