DETAILED ACTION
The amendment filed on 04/09/2026 has been entered and fully considered. Claims 1-15 are pending, of which claim 1 is amended.
Response to Amendment
In response to amendment, the examiner maintains rejection over the prior art established in the previous Office 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 § 103
The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
Claim(s) 1-3, 8-9 and 14-15 is/are rejected under 35 U.S.C. 103 as being unpatentable over Baban et al. (International Journal of Greenhouse Gas Control, 2021) (Baban).
Regarding claim 1, Baban teaches a method (abstract) comprising:
acquiring two or more 1H nuclear magnetic resonance (NMR) transverse relaxation time measurements from a formation sample at different CO2 containing states (Fig. 5, page 2, par 3, page 3, par 1, page 5, par 2), wherein at least one transverse relaxation time measurement is associated with a first CO2 slate and at least one other transverse relaxation time measurement is associated with a second CO2 state different from the first CO2 state (Fig. 5, page 2, par 3, page 3, par 1, page 5, par 2);
determining a CO2 gas wettability index, a CO2 supercritical fluid wettability index, or both based on the NMR measurements (Table 1, page 4, par 1; page 5, par 3; page 6, par 0-1, abstract).
Baban does not specifically teach calibrating the NMR measurements based on a shift in the at least one transverse relaxation time measurement and the at least one other transverse relaxation time measurement to form baseline measurement, wherein the shift is based at least on the different CO2 containing states. However, Baban teaches a relationship between the NMR measurements and the wettability index (WI) as Equation 8 (page 3).
T1/T2 = -2.25 WI + 2.25 (8)
A person skilled in the art would have appreciated that Equation 8 is a linear function typically written in the form of "y = mx + b", where "m" determines the slope of the line and "b" indicates where the line crosses the y-axis, and that m and b can be calibrated in order to fit the equation to the data. In this case, y is T1/T2, which involves the shift (change) in one or more of the two or more 1H nuclear magnetic resonance (NMR) relaxation time measurements. Thus, it would have been obvious to one of ordinary skill in the art to calibrate the NMR measurements based on a shift in the at least one transverse relaxation time measurement and the at least one other transverse relaxation time measurement to form baseline measurement, wherein the shift is based at least on the different CO2 containing states, in order to fit the equation to the data.
Further, Baban teaches that “T1-T2 and T2 measurements (note that T1 is the longitudinal relaxation time and T2 is the transverse relaxation time) were performed and then 10 PV of live brine were injected into the core at the same conditions as above to displace all dead brine with live brine. Once the pressure drop stabilized, T1-T2 and T2 responses for live-brine saturated core were obtained. Prior to scCO2 injection, the outlet pressure was maintained constant at 8 MPa (using an ISCO pump as a back-pressure regulator). Subsequently, capillary drainage pressures were measured by injecting 20 PV of scCO2 into the core plug at a constant flowrate of 0.1 ml/min, which was incrementally increased to 0.5, 1, 2, 4, 6 and 8 ml/min (Ramakrishnan and Cappiello, 1991) with multiple T1-T2 and T2 scans taken for each flow rate.” (page 2, par 3), “ “Furthermore, the capillary pressure measurements were made at the inlet of the core sample by successively increasing the CO2 flow rate, while average fluid saturations were measured via NMR T2.” (page 3, par 1). Fig. 5 notes “The entire T2 drainage curve (red) shifted left which depicts that CO2 displaced water from the large pores during drainage.”. Thus, Baban teaches that wherein the shift of T1 and T2 is based at least on the different CO2 containing states.
Baban teaches that WI denotes a wettability index, which is a general measure of wettability on a continuum (e.g., WI ≈ +1 strongly water-wet, WI ≈ −1 strongly oil-wet) (page 3, par 14), and is not limited to “water wettability”. The WI value is derived from NMR measurements reflecting fluid–rock interactions present in the system under study.
Baban explicitly teaches determining wettability indices (WI) for CO₂–brine–rock systems using NMR measurements under different CO₂-containing states, including conditions where CO₂ is present as a separate supercritical phase. Baban reports NMR-derived wettability indices after live brine saturation, CO₂ drainage, and CO₂ imbibition, and explains that: “CO₂ (either molecularly dissolved or as a separate supercritical phase) significantly reduced the hydrophilicity of the sandstone…”(abstract).
Further, Baban expressly characterizes the property being evaluated as CO₂ wettability, stating in its conclusion that: “CO₂-wettability of storage and caprock is a vital parameter as it determines storage capacities and containment security.” (page 5, par 3). This statement unambiguously demonstrates that Baban is directed to CO₂ wettability, not merely water wettability. The wettability indices reported by Baban therefore inherently correspond to CO₂ gas and CO₂ supercritical fluid wettability, as recited in amended claim 1.
Regarding claim 2, Baban teaches that the method further comprising injecting the formation sample with CO2 gas (page 2, par 2).
Regarding claim 3, Baban teaches that the method further comprising taking a second set of brine signals from the formation sample with the CO2 gas injected in the formation sample (Fig. 5, page 5, par 2).
Regarding claim 8, Baban teaches that the method further comprising injecting the formation sample with a scCO2 gas (page 2, par 2).
Regarding claim 9, Baban teaches that the method further comprising taking a second set of brine signals from the formation sample with the scCO2 gas injected in the formation sample (page 5, par 2).
Regarding claim 14, Baban teaches that wherein one of the different CO2 containing states is a CO2 free state (Table 1, page 4, par 1).
Regarding claim 15, Baban teaches that wherein one of the different CO2 containing states are at a first time during a CO2 injection into the formation sample and a second time during a storing of the formations sample this is injected with CO2 (page 5, par 2).
Claim(s) 4-7 and 10-13 is/are rejected under 35 U.S.C. 103 as being unpatentable over Baban et al. (International Journal of Greenhouse Gas Control, 2021) (Baban) in view of Li et al. (J. Geophys. Eng., 2015) (Li).
Regarding claim 4 and 10, Baban does not specifically teach that the method further comprising performing a multiexponential inversion kernel matrix with the two or more brine signals and the second set of brine signals to find a brine distribution. However, in the analogous art of core analysis, Li teaches performing a multiexponential inversion kernel matrix with the two or more brine signals and the second set of brine signals to find a brine distribution (abstract). Li teaches that “The multi-exponential inversion of a NMR relaxation signal plays a key role in core analysis and logging interpretation in the formation of porous media.” (abstract). It would have been obvious to one of ordinary skill in the art to select multiexponential inversion kernel matrix with the two or more brine signals and the second set of brine signals to find a brine distribution, because the selection is based on its suitability for the intended use.
Regarding claim 5 and 11, Baban teaches that the method further comprising cross-validating a contact angle wettability measurement with an NMR based wettability index (Table 1, page 4, par 1).
Regarding claim 6, Baban teaches that the method further comprising forming the brine wettability index from the two or more 1H NMR relaxation time measurements of the formation sample a different CO2 containing states and the two or more brine signals (Table 1, page 4, par 1).
Regarding claim 7, Baban teaches forming the CO2 gas wettability index, the CO2 supercritical fluid wettability index, or both from the brine wettability index (page 5, par 3, abstract).
Regarding claim 12, Baban teaches that the method further comprising forming the brine wettability index from one or more NMR measurements of the formation sample that is scCO2 free, the formation sample with scCO2, and the two or more brine signals (Table 1, page 4, par 1).
Regarding claim 13, Baban teaches forming the CO2 gas wettability index, the CO2 supercritical fluid wettability index, or both from the brine wettability index (page 5, par 3, abstract).
Response to Arguments
Applicant's arguments filed 04/09/2026 have been fully considered but they are not persuasive.
Applicant argues that Baban only determines a water wettability index (WI) via Equation 8 and merely uses that value to infer CO₂ wettability, but does not determine a “CO₂ gas wettability index” or “CO₂ supercritical fluid wettability index” as recited in amended claim 1. This argument is not persuasive.
(1) Baban explicitly determines wettability under CO₂ and scCO₂ conditions
Baban does not limit its analysis to water-only systems. Rather, Baban performs NMR measurements and calculates wettability indices under multiple CO₂-containing states, including:
CO₂-free (dead brine),
CO₂-saturated brine (live brine), and
CO₂ present as a separate supercritical phase (scCO₂) during drainage and imbibition.
The reported wettability indices (WI), including values such as WI = 0.26, are explicitly associated with CO₂ exposure conditions, including scCO₂ flooding. Thus, the WI values are not abstract “water-only” properties, but instead quantitative measures of rock wettability in the presence of CO₂ and scCO₂.
(2) Applicant’s “water WI vs. CO₂ WI” distinction is not technically meaningful
Applicant’s argument that Baban determines only a “water wettability index” is not supported by Baban and is based on a mischaracterization of the term “WI.” As disclosed in Baban, WI denotes a wettability index, which is a general measure of wettability on a continuum (e.g., WI ≈ +1 strongly water-wet, WI ≈ −1 strongly oil-wet) (page 3, par 14), and is not limited to “water wettability” as asserted by Applicant (remark, page 5 last line to page 6, first line). The WI value is derived from NMR measurements reflecting fluid–rock interactions present in the system under study.
In Baban, the WI values are explicitly determined under CO₂–brine–rock conditions, including conditions where CO₂ is present as a separate supercritical phase. Accordingly, the resulting WI values inherently characterize wettability of the formation in the presence of CO₂ and/or scCO₂, rather than a standalone “water wettability” property. Applicant’s attempt to reinterpret WI as exclusively “water wettability” is therefore inconsistent with Baban’s disclosure and is not persuasive.
(3) Equation 8 does not limit Baban to “water-only” wettability
Applicant relies on Equation 8 to argue that Baban determines only water wettability. This argument is not persuasive.
Equation 8 provides a mathematical relationship between NMR relaxation behavior (T₁/T₂) and a wettability index. The equation is applied to NMR measurements obtained under specific experimental conditions, including CO₂ and scCO₂ exposure. Therefore, the resulting WI values inherently reflect those CO₂-containing conditions, not an abstract water-only system.
Thus, Equation 8 does not limit Baban’s teaching to water wettability, but rather provides a general NMR-based method for quantifying wettability under the tested fluid conditions.
(4) Amended limitations regarding “different CO₂ states” and “baseline measurement”
Applicant’s amendments reciting:
measurements associated with different CO₂ states, and
calibrating based on a shift to form a “baseline measurement,”
do not distinguish over Baban.
As discussed above, Baban explicitly performs NMR measurements at multiple CO₂ states (CO₂-free, dissolved CO₂, and scCO₂). Further, Baban analyzes changes (shifts) in NMR relaxation behavior (e.g., T₁/T₂ ratios and T₂ distributions) across these states to determine wettability.
Establishing a “baseline measurement” based on such shifts represents routine comparison and normalization of experimental data, which would have been obvious to a person of ordinary skill in the art.
(5) Baban expressly concerns CO₂ wettability
Additionally, Baban expressly characterizes the property under investigation as CO₂ wettability, stating that:
“CO₂-wettability of storage and caprock is a vital parameter as it determines storage capacities and containment security.”
This confirms that Baban is directed to CO₂ wettability, not merely water wettability, further undermining Applicant’s argument.
Conclusion
THIS ACTION IS MADE FINAL. 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.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to XIAOYUN R XU, Ph. D. whose telephone number is (571)270-5560. The examiner can normally be reached M-F 8am-5pm.
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/XIAOYUN R XU, Ph.D./ Primary Examiner, Art Unit 1797
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