DETAILED ACTION
Continued Examination Under 37 CFR 1.114
A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on 3 April 2026 has been entered.
The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
Response to Amendment and Arguments
Applicant’s amendment overcomes the rejections of claims 1-5, 7, 8, 11, 12 and 15-16 over Patil, and of claim 9, 10, 12 and 17 over Patil in view of Southwell. The rejections have been withdrawn.
Applicant’s arguments in light of the amendment have been fully considered but are moot and they do not apply to the current rejection.
Claim Rejections - 35 USC § 103
Claims 1-5, 7, 8, 10-12, 15-17 and 19 are rejected under 35 U.S.C. 103 as being unpatentable over Southwell in view of US2017/0137699A1 (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
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.
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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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