DETAILED ACTION
Claims 1-5, 7, 8, 10-12, 15-17 and 19 are pending as amended on 2 July 2026, claims 6 and 18 are withdrawn from consideration.
The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
Applicant’s amendments to the claims and the remarks/arguments have been entered and fully considered.
Information Disclosure Statement
The information disclosure statement (IDS) submitted on 2 July 2026 was filed after the mailing date of the first Office action on 17 April 2026. The submission is in compliance with the provisions of 37 CFR 1.97. Accordingly, the information disclosure statement is being considered by the examiner.
Response to Amendment and Arguments
Applicant’s arguments have been fully considered but are not persuasive.
Applicant argues that Southwell is directed toward avoiding gelation while Song is directed toward achieving advantage in polymer-based gels. The examiner notes that Southwell is to avoid gelation of colloidal silica under high temperature and high salt conditions ([0015] and [0057]), not to avoid polymer thickener. Southwell expressly discloses that “In order to enhance the viscosity of the chemical fluid, a thickener, selected from the group consisting of a water-soluble polymer hydroxyethyl cellulose and a salt thereof, hydroxypropylmethyl cellulose and a salt thereof, carboxymethyl cellulose and a salt thereof, pectin, guar gum xanthan gum, tamarind gum, carrageenan, and the like may be further added” ([0130]). Song teaches that ascorbic acid, as an inherent stabilizer, can be added to high temperature well treatment fluid to stabilize the viscosity ([0007] and [0018]). Thus the examiner maintains that at the time the invention was made it would have been obvious for a person of ordinary skill in the art to add the ascorbic acid stabilizer of Song in the chemical fluid of Southwell in order to provide high temperature viscosity stability ([0007]), which is desirable by Southwell ([0131]).
Applicant argues that adding an antioxidant provide unexpected results of the claimed DLS ratios. However, as acknowledged by Applicant, Southwell discloses the claimed DLS ratio ([0285], [0286]), thus the claimed DLS ratio is not an unexpected advantage.
Applicant argues that Southwell’s test were conducted under different test conditions and would result in ratios similar to instant Comparative example 2 if were subjected to the instant test conditions. However, instant Comparative example 2 has a test condition of 100°C X10hr, while the claimed DLS ratio is under a test condition of 100°C X720hr. Thus Applicant's showing of unexpected results is not commensurate in the scope with the claims. MPEP 716.02(d) states: Whether the unexpected results are the result of unexpectedly improved results or a property not taught by the prior art, the "objective evidence of nonobviousness must be commensurate in scope with the claims which the evidence is offered to support." In other words, the showing of unexpected results must be reviewed to see if the results occur over the entire claimed range. In re Clemens, 622 F.2d 1029, 1036, 206 USPQ 289, 296 (CCPA 1980). See also In re Peterson, 315 F.3d 1325, 1329-31,65 USPQ2d 1379, 1382-85 (Fed. Cir. 2003); In re Grasselli, 713 F.2d 731,741,218 USPQ 769, 777 (Fed. Cir. 1983).
In view of the foregoing, when all of the evidence is considered, the totality of the rebuttal evidence of nonobviousness fails to outweigh the evidence of obviousness. Therefore previous rejections are maintained and reiterated below in its entirety.
Claim Rejections - 35 USC § 103
Claims 1-5, 7, 8, 10-12, 15-17 and 19 stand rejected under 35 U.S.C. 103 as being unpatentable over Southwell in view of Song.
Regarding claims 1-3, 7, 11, 15 and 19, Southwell teaches a crude oil recovery chemical fluid which exhibits excellent resistance to high temperature and salt, comprising a silane compound; an aqueous silica sol having an average particle diameter of from about 3 to about 200 nm, which meets the claimed particle size; two or more anionic surfactants, and one or more nonionic surfactants ([0017]), wherein the aqueous silica sol contains silica particles in which at least a part of the silane compound is bonded on the surface of at least a part of the silica particles in the sol ([0018]), wherein the silane compound includes 3-glycidoxypropyltrimethoxysilane ([0018] and [0085]), which meets the claimed formula (I) wherein R1 is a glycidoxypropyl group, and R2 is an methoxy group, a is 1.
Southwell teaches the ratio of the DLS average particle diameter after a high temperature and salt resistance test/the DLS average particle diameter of the chemical fluid is 1.5 or less exemplified as a high temperature and salt resistance test at 100° C. for 1800 hours in an environment of a salt concentration of 4% by mass([0074], [0144] and [0286]), which meets the claimed DLS ratio.
Southwell further teaches the fluid has a pH of 2-12 ([0059]-[0061]), which overlaps with the claimed pH and a prima facie case of obviousness exists. In re Wertheim, 541 f. 2d 257,191 USPQ 90(CCPA 1976). See MPEP 2144.05.I.
Southwell further teaches in a case where the crude oil recovery chemical fluid has a pH of from about 7 to about 12, the anionic surfactants are present in a mass ratio of from about 0.4 to about 5.0 based on the silica solid content of the aqueous silica sol; and in a case where the crude oil recovery chemical fluid has a pH of from about 2 to about 7, the anionic surfactants are present in a mass ratio of from about 0.001 to about 0.4 based on the silica solid content of the aqueous silica sol ([0134] and [0135]).
Southwell does not teach the presence of ascorbic acid in the chemical fluid, neither the claimed amount.
Song teaches ascorbic acid can be added to high temperature well treatment fluid to stabilize the viscosity ([0007] and [0018]), wherein the ascorbic acid is added in an amount of from 1-50 ppt ([0044]), exemplified as 10lb/1000gal ([0051]), i.e., about 0.12% calculated by the examiner based on 1 gallon water =8.33 pound.
At the time the invention was made it would have been obvious for a person of ordinary skill in the art to add the ascorbic acid stabilizer of Song and amount in the chemical fluid of Southwell. The rationale to do so would have been the motivation provided by the teachings of Song that to do so would predictably provide high temperature viscosity stability ([0007]), which is desirable by Southwell ([0131]).
Regarding claim 4, Southwell exemplifies a silica sol of pH of 3.1 ([0164]), which meets the claimed pH.
Regarding claims 5 and 8, Southwell teaches that the aqueous silica sol is present in an amount of from about 0.01% by mass to about 30% by mass, based on the total mass of the crude oil recovery chemical fluid, in terms of silica solid content([0020]), which meets the claimed amount; thus the ratio of ascorbic acid to silica is about 0.004 to 12, estimated by the examiner based on 10lb/1000gallon , i.e., 0.12% of ascorbic acid as taught by Song ([0051]), which overlaps with the claimed ratio and a prima facie case of obviousness exists. In re Wertheim, 541 f. 2d 257,191 USPQ 90(CCPA 1976). See MPEP 2144.05.I.
Regarding claim 10 , Southwell teaches the silane compound is present in a ratio of from about 0.1 to about 10.0 of silane compound based on the mass of silica solid content of the aqueous silica sol ([0021] and [0093]), which meets the claimed ratio.
Regarding claim 12 , Southwell teaches the surfactants are present in an amount of from about 0.001% by mass to about 20% by mass, based on the total mass of the crude oil recovery chemical fluid ([0023]), which meets the claimed amount.
Regarding claim 16 , Southwell exemplified a salt concentration of 4% by mass ([0144]).
Regarding claim 17 , Southwell teaches a thickener, selected from the group consisting of a water-soluble polymer hydroxyethyl cellulose and a salt thereof, hydroxypropylmethyl cellulose and a salt thereof, carboxymethyl cellulose and a salt thereof, pectin, guar gum xanthan gum, tamarind gum, carrageenan can be added to aqueous silica sols to enhance the viscosity ([0131]).
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 AIQUN LI whose telephone number is (571)270-7736. The examiner can normally be reached Monday-Friday 9:00 am -4:00 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, Randy Gulakowski can be reached at 571-2721302. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/AIQUN LI/Ph.D., Primary Examiner, Art Unit 1766
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