# US 11,906,417 B2 · Restoring core samples > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,906,417 B2 - Document ID: US11906417B2 - Status: Granted - Kind: B2 - Application number: 17/569,141 - Filed: 2022-01-05 - Published: 2023-07-06 - Granted: 2024-02-20 - Earliest claimed: 2022-01-05 - Assignees: Saudi Arabian Oil Company - Applicants: Saudi Arabian Oil Company - Inventors: Ying Wang; Ming Han; Dongqing Cao; Jinxun Wang - Web page: https://patentgrep.com/patent/US11906417B2 ## CPC - G01N 15/0826: {and measuring fluid flow rate, i.e. permeation rate or pressure change} - G01N 15/08: Investigating permeability, pore-volume, or surface area of porous materials - G01N 15/0806: {Details, e.g. sample holders, mounting samples for testing} - G01N 15/082: {Investigating permeability by forcing a fluid through a sample} - G01N 15/088: {Investigating volume, surface area, size or distribution of pores; Porosimetry} - E21B 43/20: Displacing by water - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) - E21B: EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS ## Abstract The systems and method described in this specification relate to at least partially restoring porosity and brine permeability of carbonate core samples. The systems and methods include extracting a carbonate core sample from a subterranean formation. The extracted carbonate core sample is inserted into a core flooding test machine. A first porosity and a first brine permeability of the extracted carbonate core sample is measured. A fluid is pumped through the extracted carbonate core sample to flood the carbonate core sample. The fluid includes at least one of a high-molecular weight polymer solution and a gel particle solution. The systems and methods include at least partially restoring the porosity and the brine permeability of the carbonate core sample by pumping an oxidizing solution through the flooded carbonate core sample and heating the carbonate core sample to a temperature of at least 60° C. after pumping the oxidizing solution through the carbonate core sample. ## Claims ### Claim 1 A method of at least partially restoring carbonate core samples, the method comprising: extracting a carbonate core sample from a subterranean formation; inserting the extracted carbonate core sample into a core flooding test machine; measuring a first porosity and a first brine permeability of the extracted carbonate core sample; pumping a fluid through the extracted carbonate core sample to flood the carbonate core sample, the fluid comprising at least one of a high-molecular weight polymer solution and a gel particle solution; and at least partially restoring the porosity and the brine permeability of the carbonate core sample by: pumping an oxidizing solution through the flooded carbonate core sample; and heating the carbonate core sample to a first temperature of at least 60° C. after pumping the oxidizing solution through the carbonate core sample. ### Claim 2 (depends on 1) The method of claim 1, wherein the oxidizing solution comprises at least one of NaClO, HClO, K2S2O8, NaBrO, KClO3, and KMnO4. ### Claim 3 (depends on 2) The method of claim 2, wherein the oxidizing solution comprises 1% NaClO in 2% KCl. ### Claim 4 (depends on 3) The method of claim 3, wherein heating the carbonate core sample to the first temperature comprises heating the carbonate core sample to a temperature between 60° C. and 100° C. ### Claim 5 (depends on 4) The method of claim 4, wherein at least partially restoring the porosity and the brine permeability of the carbonate core sample further comprises maintaining the temperature between 60° C. and 100° C. for a duration between 1 hour and 4 hours. ### Claim 6 (depends on 5) The method of claim 5, wherein the fluid further comprises a surfactant and the at least partially restoring the porosity and the brine permeability of the carbonate core sample further comprises heating the carbonate core sample to a second temperature between 350° C. and 600° C. ### Claim 7 (depends on 6) The method of claim 6, wherein at least partially restoring the porosity and the brine permeability of the carbonate core sample further comprises maintaining the second temperature between 350° C. and 600° C. for a duration between 25 minutes and 4 hours. ### Claim 8 (depends on 6) The method of claim 6, wherein heating the carbonate core sample to the second temperature between 350° C. and 600° C. comprises controlling the second temperature to heat the carbonate core sample at a rate of between 4° C./min and 6° C./min. ### Claim 9 (depends on 6) The method of claim 6, wherein heating the carbonate core sample to the second temperature between 350° C. and 600° C. comprises controlling the second temperature to heat the carbonate core sample at a rate having a stepwise increase of temperature in 50° C. increments with a dwell time of 15 minutes per increment. ### Claim 10 (depends on 5) The method of claim 5, wherein pumping the oxidizing solution through the carbonate core sample comprises: pumping a predetermined volume of an oxidizing solution comprising 1% NaClO in 2% KCl at a volumetric rate of between 0.5 ml/min and 2 ml/min through the carbonate core sample, wherein the predetermined volume of the pumped oxidizing solution is at least 5 times greater than a volume of the carbonate core sample. ### Claim 11 (depends on 10) The method of claim 10, wherein at least partially restoring the porosity and the brine permeability of the flooded carbonate core sample further comprises: pumping a predetermined volume of a non-oxidizing solution through the carbonate core sample at a volumetric rate of between 4 ml/min and 6 ml/min after heating the carbonate core sample to the temperature between 60° C. and 100° C. and after maintaining the temperature between 60° C. and 100° C. for the duration between 1 hour and 4 hours, wherein the non-oxidizing solution comprises 2% KCl, and wherein the predetermined volume of the pumped non-oxidizing solution is at least 5 times greater than the volume of the carbonate core sample. ### Claim 12 (depends on 1) The method of claim 1, wherein at least partially restoring the porosity and the brine permeability of the carbonate core sample further comprises: measuring a second porosity and a second brine permeability of the extracted carbonate core sample; determining (i) whether the measured second porosity is at least 85% of the measured first porosity and (ii) whether the measured second brine permeability is at least 85% of the measured first brine permeability; and responsive to determining that at least one of the measured second porosity is not at least 85% of the measured first porosity and the measured second brine permeability is not at least 85% of the measured first brine permeability, pumping the oxidizing solution through the carbonate core sample; and heating the carbonate core sample to the first temperature of at least 60° C. after pumping the oxidizing solution through the carbonate core sample. ### Claim 13 (depends on 1) The method of claim 1, wherein the fluid comprises a high-molecular-weight acrylamide-based polymer solution, a super-molecular-weight polyacrylamide-based gel particle solution, or both. ### Claim 14 A method of at least partially restoring carbonate core samples, the method comprising: inserting a carbonate core sample extracted from a subterranean formation into a core flooding test machine; measuring a first porosity and a first brine permeability of the carbonate core sample; pumping a fluid through the carbonate core sample to flood the carbonate core sample, the fluid comprising at least one of a high-molecular weight polymer solution and a gel particle solution; and at least partially restoring the porosity and the brine permeability of the carbonate core sample by: pumping an oxidizing solution through the carbonate core sample, the oxidizing solution comprises 1% NaClO in 2% KCl; heating the carbonate core sample to a temperature of between 60° C. and 600° C.; and maintaining the temperature for at least 25 minutes. ### Claim 15 (depends on 14) The method of claim 14, wherein heating the carbonate core sample to a temperature between 60° C. and 600° C. comprises heating the carbonate core sample to a temperature between 90° C. and 100° C., and wherein maintaining the temperature for at least 25 minutes comprises maintaining the temperature for between 6 hours and 10 hours. ### Claim 16 (depends on 14) The method of claim 14, wherein the fluid further comprises a surfactant, wherein heating the carbonate core sample to a temperature between 60° C. and 600° C. comprises heating the carbonate core sample to a temperature between 220° C. and 600° C., and wherein maintaining the temperature for at least 25 minutes comprises maintaining the temperature for between 25 minutes and 4 hours. ### Claim 17 (depends on 14) The method of claim 14, wherein heating the carbonate core sample to a temperature of at least 60° C. comprises heating the carbonate core sample to a temperature between 60° C. and 100° C., and wherein maintaining the temperature for at least 25 minutes comprises maintaining the temperature for between 1 hour and 4 hours. ### Claim 18 (depends on 14) The method of claim 14, wherein pumping the oxidizing solution through the carbonate core sample comprises pumping a predetermined volume of the oxidizing solution through the carbonate core sample at a volumetric rate of between 0.5 ml/min and 2 ml/min, wherein the predetermined volume of the pumped oxidizing solution is at least 5 times greater than a volume of the carbonate core sample. ### Claim 19 (depends on 14) The method of claim 14, wherein at least partially restoring the porosity and the brine permeability of the carbonate core sample further comprises pumping a predetermined volume of a non-oxidizing solution through the carbonate core sample at a volumetric rate of between 4 ml/min and 6 ml/min, wherein the predetermined volume of the pumped non-oxidizing solution is at least 5 times greater than a volume of the carbonate core sample. ### Claim 20 (depends on 14) The method of claim 14, wherein at least partially restoring the porosity and the brine permeability of the carbonate core sample further comprises: determining (i) whether the measured second porosity is at least 85% of the measured first porosity and (ii) whether the measured second brine permeability is at least 85% of the measured first brine permeability; and responsive to determining that at least one of the measured second porosity is not at least 85% of the measured first porosity and the measured second brine permeability is not at least 85% of the measured first brine permeability, pumping the oxidizing solution through the carbonate core sample; heating the carbonate core sample to the temperature of between 60° C. and 600° C.; and maintaining the temperature for at least 25 minutes.