# US 11,111,426 B2 · In-situ salinity adjustment to improve waterflooding performance in oil-wet carbonate reservoirs > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,111,426 B2 - Document ID: US11111426B2 - Status: Granted - Kind: B2 - Application number: 16/424,098 - Filed: 2019-05-28 - Published: 2019-12-05 - Granted: 2021-09-07 - Earliest claimed: 2018-05-30 - Assignees: Saudi Arabian Oil Company - Applicants: Saudi Arabian Oil Company - Inventors: Mohammed Badri Al-Otaibi; Dong Kyu Cha; Ali Abdallah Al-Yousef - Web page: https://patentgrep.com/patent/US11111426B2 ## CPC - C09K 8/588: characterised by the use of specific polymers {(polymeric surfactants C09K8/584)} - E21B 43/20: Displacing by water - C09K 2208/10: Nanoparticle-containing well treatment fluids - C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE - E21B: EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS ## Abstract A composition for increased hydrocarbon production from a hydrocarbon-bearing reservoir. The composition includes a saltwater solution suitable for injection into the hydrocarbon-bearing reservoir for water flooding, the saltwater solution having a salinity; and a plurality of nanocapsules, where the nanocapsules are operable to be suspended amongst the saltwater solution, where the nanocapsules have an overall positively charged outer surface at respective outer shells of the nanocapsules, where the nanocapsules encapsulate water molecules within the nanocapsules, and where the nanocapsules are operable to release the water molecules in the hydrocarbon-bearing reservoir proximate overall negatively charged zones. ## Claims ### Claim 1 A composition for increased hydrocarbon production from a hydrocarbon-bearing reservoir, the composition comprising: a saltwater solution suitable for injection into the hydrocarbon-bearing reservoir for water flooding, the saltwater solution having a salinity; and a plurality of nanocapsules, where the nanocapsules are operable to be suspended amongst the saltwater solution, where the nanocapsules have an overall positively charged outer surface at respective outer shells of the nanocapsules, where the nanocapsules encapsulate water molecules without salt or minerals within the nanocapsules, and where the nanocapsules are operable to release the water molecules in the hydrocarbon-bearing reservoir proximate overall negatively charged zones to reduce salinity and alter wettability via release of water molecules in situ proximate an area of release. ### Claim 2 (depends on 1) The composition of claim 1, where the outer shells comprise a polymeric material to provide the overall positively charged outer surface. ### Claim 3 (depends on 1) The composition of claim 1, where the outer shells comprise a resin material to provide the overall positively charged outer surface. ### Claim 4 (depends on 1) The composition of claim 1, where the outer shells comprise a moiety grafted to the outer shells to provide the overall positively charged outer surface. ### Claim 5 (depends on 1) The composition of claim 1, where the nanocapsules are operable to release the water molecules in the hydrocarbon-bearing reservoir proximate overall negatively charged zones comprising oil or natural gas. ### Claim 6 (depends on 1) The composition of claim 1, wherein the plurality of nanocapsules are present in the composition in an amount operable to release an amount of water molecules wherein surface charge of a rock is changed from positive to negative to drive out an overall negatively charged oil layer proximate the rock. ### Claim 7 (depends on 1) The composition of claim 1, where the overall positively charged outer surface is suitable to prevent the plurality of nanocapsules from releasing the water molecules near an overall positively charged zone in the hydrocarbon-bearing reservoir. ### Claim 8 (depends on 7) The composition of claim 7, where the overall positively charged zone in the reservoir comprises water-wet carbonate rock. ### Claim 9 (depends on 1) The composition of claim 1, where the nanocapsules are operable to release the water molecules in the hydrocarbon-bearing reservoir proximate overall negatively charged zones comprising a carboxylate group. ### Claim 10 (depends on 1) The composition of claim 1, where the saltwater solution comprises seawater. ### Claim 11 A method for increasing hydrocarbon production from a hydrocarbon-bearing reservoir, the method comprising the steps of: preparing a saltwater solution suitable for injection into the hydrocarbon-bearing reservoir for water flooding, the saltwater solution having a salinity; adding to the saltwater solution a plurality of nanocapsules to form an enhanced recovery suspension, where the nanocapsules are operable to be suspended amongst the saltwater solution, where the nanocapsules have an overall positively charged outer surface at respective outer shells of the nanocapsules, where the nanocapsules encapsulate water molecules without salt or minerals within the nanocapsules, and where the nanocapsules are operable to release the water molecules in the hydrocarbon-bearing reservoir proximate overall negatively charged zones to reduce salinity and alter wettability via release of water molecules in situ proximate an area of release; and injecting the enhanced recovery suspension into the hydrocarbon-bearing reservoir to increase hydrocarbon production. ### Claim 12 (depends on 11) The method of claim 11, where the outer shells comprise a polymeric material to provide the overall positively charged outer surface. ### Claim 13 (depends on 11) The method of claim 11, where the outer shells comprise a resin material to provide the overall positively charged outer surface. ### Claim 14 (depends on 11) The method of claim 11, further comprising the step of grafting a moiety to the outer shells to provide the overall positively charged outer surface. ### Claim 15 (depends on 11) The method of claim 11, where the nanocapsules are operable to release the water molecules in the hydrocarbon-bearing reservoir proximate overall negatively charged zones comprising oil or natural gas. ### Claim 16 (depends on 11) The method of claim 11, where the step of adding includes adding the plurality of nanocapsules in an amount operable to release an amount of water molecules wherein surface charge of a rock is changed from positive to negative to drive out an overall negatively charged oil layer proximate the rock. ### Claim 17 (depends on 11) The method of claim 11, where the overall positively charged outer surface is suitable to prevent the plurality of nanocapsules from releasing the water molecules near an overall positively charged zone in the hydrocarbon-bearing reservoir. ### Claim 18 (depends on 17) The method of claim 17, where the overall positively charged zone in the reservoir comprises water-wet carbonate rock. ### Claim 19 (depends on 11) The method of claim 11, where the nanocapsules are operable to release the water molecules in the hydrocarbon-bearing reservoir proximate overall negatively charged zones comprising a carboxylate group. ### Claim 20 (depends on 11) The method of claim 11, where the saltwater solution comprises seawater.