DETAILED ACTION
The amendment and RCE filed on 12/17/2025 has been entered and fully considered. Claims 1-15 are pending, of which claims 1, 7 and 13 are 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) 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);
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 one or more of the two or more 1H nuclear magnetic resonance (NMR) relaxation time measurements to form base signal. 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 NMR measurements on a shift in one or more of the two or more 1H nuclear magnetic resonance (NMR) relaxation time measurements to form a reference signal, 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 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 12/17/2025 have been fully considered but they are not persuasive.
Applicant argues that Baban merely discloses calculating “water wettability” to observe a general effect of CO₂ displacement and is silent regarding determining a CO₂ gas wettability index or a CO₂ supercritical fluid wettability index. This argument is not supported by the disclosure of Baban.
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.
Applicant’s attempt to distinguish “water wettability” from “CO₂ wettability” is unpersuasive because Baban evaluates wettability specifically in the presence of CO₂, including both dissolved CO₂ and scCO₂, and attributes observed changes in wettability to CO₂–rock interactions. Accordingly, Baban teaches or at least renders obvious the limitation of “determining a CO₂ gas wettability index, a CO₂ supercritical fluid wettability index, or both.”
Conclusion
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/XIAOYUN R XU, Ph.D./ Primary Examiner, Art Unit 1797