Prosecution Insights
Last updated: May 04, 2026
Application No. 18/161,556

MECHANIZED CENTRIFUGE WITH SOLIDS CONTENT ANALYZER TO CONDITION DRILLING FLUIDS

Final Rejection §103
Filed
Jan 30, 2023
Examiner
LIU, SHUYI S
Art Unit
1774
Tech Center
1700 — Chemical & Materials Engineering
Assignee
Saudi Arabian Oil Company
OA Round
2 (Final)
73%
Grant Probability
Favorable
3-4
OA Rounds
0m
Est. Remaining
99%
With Interview

Examiner Intelligence

Grants 73% — above average
73%
Career Allowance Rate
334 granted / 460 resolved
+7.6% vs TC avg
Strong +27% interview lift
Without
With
+27.1%
Interview Lift
resolved cases with interview
Typical timeline
3y 1m
Avg Prosecution
57 currently pending
Career history
517
Total Applications
across all art units

Statute-Specific Performance

§101
0.6%
-39.4% vs TC avg
§103
45.2%
+5.2% vs TC avg
§102
17.7%
-22.3% vs TC avg
§112
34.2%
-5.8% vs TC avg
Black line = Tech Center average estimate • Based on career data from 460 resolved cases

Office Action

§103
FINAL 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 . Response to Arguments Applicant’s arguments filed 24 February 2026 with respect to the pending claims have been considered but are moot because the new ground of rejection does not rely on any reference applied in the prior rejection of record for any teaching or matter specifically challenged in the argument. Drawings The drawings were received on 30 January 2023. These drawings are acceptable. Claim Rejections - 35 USC § 103 In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status. 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 1-9 and 11-20 are rejected under 35 U.S.C. 103 as being unpatentable over Stone (U.S. Patent No. 10,155,230) in view of Hensley et al. (U.S. Patent Application Pub. No. 2002/0074269, hereinafter Hensley). Regarding claim 1, Stone discloses a drilling fluid conditioning system (Abstract) comprising: a centrifuge (10, Fig. 2) configured to receive solids-laden drilling fluid via a centrifuge pump (44, Fig. 2) and discharge conditioned drilling fluid and separated solids using centrifuge operational parameters (pump 44 is drive by VFD 46 which is controlled by control system 60, col. 7 lines 4-16 ); a centrifuge feed pit (feed tank 40, Fig. 2) comprising the solids laden drilling fluid and a first solids content sensor (low gravity drilled solids sensor, low gravity commercial solids sensor, and high gravity commercial solids sensor at preferably the slurry feed input to centrifuge 10 and/or advantageously the output from centrifuge 10, col. 12 line 58 – col. 13 line 5); a centrifuge discharge pit (holding tank 110, Fig. 2) and a second solids content sensor (low gravity drilled solids sensor, low gravity commercial solids sensor, and high gravity commercial solids sensor at preferably the slurry feed input to centrifuge 10 and/or advantageously the output from centrifuge 10, col. 12 line 58 – col. 13 line 5); and a computer system (60, Fig. 2) electronically connected to the first solids content sensor, the second solids content sensor, and the centrifuge (col. 11 line 57 – col. 14 line 3), wherein the computer system is configured to analyze results from the first solids content sensor and the second solids content sensor using a set of goal drilling fluid parameters (col. 9 line 59 – col. 10 line 40) and send an instruction to the centrifuge based on the analyzed results of the solids content sensors and wherein the instruction comprises a first instruction to stop the centrifuge or a second instruction to adjust the centrifuge operational parameters (“the control system PM calculates the value of an optimization algorithm, such as the algorithm above. The control system PM measures the performance using at least one sensor. If the performance is not optimal, as defined by the algorithm, then the control system will select a parameter to change, for example, one of the rotational speed of bowl 12, the rotational speed of conveyor 18 and speed of feed pump 44”, col. 10 lines 41 – 56), but does not disclose a feedback line connected to the centrifuge discharge pit and configured to transport the conditioned drilling fluid from the centrifuge discharge pit back to the centrifuge feed pit. Hensley discloses analogous art related to a drilling mud clarification or reclamation system, comprising a feedback line (line 50, Fig. 2) configured to transport the conditioned drilling fluid (liquid discharge 42, Fig. 1) back to the centrifuge feed pit (tank 16, Fig. 1). It would have been obvious for one having ordinary skill in the art before the effective filing date of the claimed invention to have provided a feedback line from the discharge pit (holding tank 110, Fig. 2) of Stone’s drilling fluid conditioning system to the feed tank/pit in order to allow for recirculation and reuse of the drilling fluid, as taught by Hensley (para. [0010], [0022]-[0023], Henley). Regarding claim 2, Stone discloses wherein the centrifuge feed pit (feed tank 40, Fig. 2) further comprises a first specific gravity sensor (specific gravity can be measured by Coriolis mass flow sensor 111, Fig. 2). Regarding claim 3, Stone discloses wherein the centrifuge discharge pit (holding tank 110, Fig. 2) further comprises a second specific gravity sensor (specific gravity can be measured by Coriolis mass flow sensor 112, Fig. 2). Regarding claim 4, Stone discloses wherein the computer system is further configured to analyze results from the first specific gravity sensor and the second specific gravity sensor and send the instruction to the centrifuge based on the analyzed results of the specific gravity sensors and the solids content sensors (col. 13 line 55 – col. 14 line 3). Regarding claim 5, Stone discloses a solids accumulation pit (solids collection box 122, Fig. 2) comprising the separated solids. Regarding claim 6, Stone discloses a solids discharge line (discharge pipe 120, Fig. 2) connected to the centrifuge (10, Fig. 2) and the solids accumulation pit (solids collection box 122, Fig. 2). Regarding claim 7, Stone discloses a centrifuge feed line (conduit 42, Fig. 2) connected to the centrifuge (10, Fig. 2) and the centrifuge feed pit (feed tank 40, Fig. 2) and configured to transport the solids-laden drilling fluid from the centrifuge feed pit to the centrifuge (col. 6 lines 41-47). Regarding claim 8, Stone discloses a liquid discharge line (liquid discharge pipe 105, Fig. 2) connected to the centrifuge (10, Fig. 2) and the centrifuge discharge pit (holding tank 110, Fig. 2) and configured to transport the conditioned drilling fluid from the centrifuge to the centrifuge discharge pit (col. 12 lines 13-14). Regarding claim 9, Stone discloses a wellbore discharge line connected to the centrifuge feed pit (feed tank 40, Fig. 2) and configured to transport the solids-laden drilling fluid from a wellbore to the centrifuge feed pit (“the feed tank receives solids laden drilling mud directly from the well”, col. 3 lines 10-12; a wellbore discharge line is assumed to be inherently and necessarily present to connect the feed tank to the well). Regarding claim 11, Stone discloses a method for conditioning drilling fluid (Abstract), the method comprising: pumping solids-laden drilling fluid from a centrifuge feed pit (feed tank 40, Fig. 2) to a centrifuge (10, Fig. 2) using a centrifuge pump (44, Fig. 2); measuring a first solids content of the solids-laden drilling fluid using a first solids content sensor (low gravity drilled solids sensor, low gravity commercial solids sensor, and high gravity commercial solids sensor at preferably the slurry feed input to centrifuge 10 and/or advantageously the output from centrifuge 10, col. 12 line 58 – col. 13 line 5), conditioning the solids laden drilling fluid using the centrifuge and centrifuge operational parameters (pump 44 is drive by VFD 46 which is controlled by control system 60, col. 7 lines 4-16 ); discharging conditioned drilling fluid from the centrifuge to a centrifuge discharge pit (holding tank 110, Fig. 2); measuring a second solids content of the conditioned drilling fluid using a second solids content sensor (low gravity drilled solids sensor, low gravity commercial solids sensor, and high gravity commercial solids sensor at preferably the slurry feed input to centrifuge 10 and/or advantageously the output from centrifuge 10, col. 12 line 58 – col. 13 line 5) connected to the centrifuge discharge pit; analyzing the first solids content and the second solids content using a computer system and a set of goal drilling fluid parameters (col. 9 line 59 – col. 10 line 40); and sending instruction to the centrifuge based on the solids content analyzation, wherein the instruction comprises a first instruction to stop the centrifuge or a second instruction to adjust the centrifuge operational parameters (“the control system PM calculates the value of an optimization algorithm, such as the algorithm above. The control system PM measures the performance using at least one sensor. If the performance is not optimal, as defined by the algorithm, then the control system will select a parameter to change, for example, one of the rotational speed of bowl 12, the rotational speed of conveyor 18 and speed of feed pump 44”, col. 10 lines 41 – 56), but does not disclose directing, through a feedback line connecting the discharge pit and the centrifuge feed pit, conditioned drilling fluid from the centrifuge discharge pit back to the centrifuge feed pit. Hensley discloses directing, through a feedback line (line 50, Fig. 1) connecting the discharge line 42 (Fig. 1) and the centrifuge feed pit (tank 16, Fig. 1), conditioned drilling fluid (liquid discharge in line 42, Fig. 1) from the centrifuge discharge line back to the centrifuge feed pit. It would have been obvious for one having ordinary skill in the art before the effective filing date of the claimed invention to have provided a feedback line from the discharge pit (holding tank 110, Fig. 2) in Stone’s method to the feed tank/pit in order to allow for recirculation and reuse of the drilling fluid, as taught by Hensley (para. [0010], [0022]-[0023], Henley). Regarding claim 12, Stone discloses measuring a first specific gravity of the solids-laden drilling fluid using a first specific gravity sensor (specific gravity can be measured by Coriolis mass flow sensor 111, Fig. 2) connected to the centrifuge feed pit (feed tank 40, Fig. 2). Regarding claim 13, Stone discloses measuring a second specific gravity of the conditioned drilling fluid using a second specific gravity sensor (specific gravity can be measured by Coriolis mass flow sensor 112, Fig. 2) connected to the centrifuge discharge pit (holding tank 110, Fig. 2). Regarding claim 14, Stone discloses analyzing the first specific gravity and the second specific gravity using the computer system (col. 13 line 55 – col. 14 line 3). Regarding claim 15, Stone discloses analyzing the first specific gravity and the second specific gravity further comprises classifying the second specific gravity as low gravity solids or high gravity solids (data used by the control system include the % by volume and mass of low gravity and high gravity solids content measured by sensors located at the output of centrifuge 10, col. 12 line 58 – col. 13 line 5; from these data the computer system would be able to determine if the fluid has low gravity solids or high gravity solids). Regarding claim 16, Stone discloses sending instruction to the centrifuge further comprises sending the instruction to the centrifuge based on the solids content analyzation and the specific gravity analyzation (col. 11 line 57 – col. 14 line 3, all measurements from the sensors including those of solids content and specific gravity are sent to and analyzed by the control system). Regarding claim 17, Stone discloses wherein the centrifuge operational parameters comprises a speed of the centrifuge (“[i]f the performance is not optimal, as defined by the algorithm, then the control system will select a parameter to change, for example, one of the rotational speed of bowl 12, the rotational speed of conveyor 18 and speed of feed pump 44”, col. 10 lines 41 – 56). Regarding claim 18, Stone discloses wherein the instruction comprises increasing the speed of the centrifuge if the second specific gravity is classified as being low gravity solids (centrifuge is set to high speed decanter separating factor 1200-2100 rpm for 2-5 micrometer particle size, i.e., low gravity solids, col. 2 lines 38-39). Regarding claim 19, Stone discloses wherein the instruction comprises decreasing the speed of the centrifuge if the second specific gravity is classified as being high gravity solids (centrifuge is set to low speed decanting for barite, i.e., high gravity solids, removal, separator factor 500-700 rpm, 4-7 micrometer particle size, specific gravity of at least 4.20 g/cm3, col. 2 lines 19-21). Regarding claim 20, Stone discloses wherein conditioning the solids-laden drilling fluid further comprises discharging separated solids from the centrifuge (10, Fig. 2) to a solids accumulation pit (solids collection box 122, Fig. 2). Claim 10 is rejected under 35 U.S.C. 103 as being unpatentable over Stone in view of Hensley, as applied to claim 1 above, and further in view of Zazula et al. (U.S. Patent Application Pub. No. 2016/0184741, hereinafter Zazula). Regarding claim 10, the combination of Stone and Hensley does not explicitly teach a wellbore feed line connected to the centrifuge discharge pit and configured to transport the conditioned drilling fluid from the centrifuge discharge pit to a drill string. Zazula discloses analogous art related to a drilling fluid system, comprising a wellbore feed line (discharge line 118, Fig. 1A) connected to the centrifuge discharge pit (mud tank 112, Fig. 1A) and configured to transport the conditioned drilling fluid from the centrifuge discharge pit to a drill string (para. [0024]). It would have been obvious for one having ordinary skill in the art before the effective filing date of the claimed invention to have provided the system of the combination of Stone and Hensley with the wellbore feed line of Zazula for the purpose of returning cleaned and treated drilling mud back down into the wellbore (para. [0024], Zazula). Conclusion Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). 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 SHUYI S LIU whose telephone number is (571)272-0496. The examiner can normally be reached MON - FRI 9:30AM - 2:30PM EST. 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, Claire Wang can be reached at 571-270-1051. 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. /Shuyi S. Liu/Examiner, Art Unit 1774 /CLAIRE X WANG/Supervisory Patent Examiner, Art Unit 1774
Read full office action

Prosecution Timeline

Jan 30, 2023
Application Filed
Nov 15, 2025
Non-Final Rejection — §103
Feb 24, 2026
Response Filed
Mar 16, 2026
Final Rejection — §103 (current)

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Prosecution Projections

3-4
Expected OA Rounds
73%
Grant Probability
99%
With Interview (+27.1%)
3y 1m (~0m remaining)
Median Time to Grant
Moderate
PTA Risk
Based on 460 resolved cases by this examiner. Grant probability derived from career allowance rate.

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