# US 12,180,814 B2 · System and method for enhanced oil recovery utilizing alternating stacked liquid and gas slugs > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,180,814 B2 - Document ID: US12180814B2 - Status: Granted - Kind: B2 - Application number: 17/802,918 - Filed: 2021-02-28 - Published: 2023-05-18 - Granted: 2024-12-31 - Earliest claimed: 2020-02-28 - Assignees: Eor Etc LLC - Applicants: Eor Etc LLC - Inventors: Stuart Lindsey Scott; Adrian Paul Williams - Web page: https://patentgrep.com/patent/US12180814B2 ## CPC - E21B 43/166: {Injecting a gaseous medium; Injecting a gaseous medium and a liquid medium (CO2 injection E21B43/164; steam injection E21B43/24)} - E21B 43/20: Displacing by water - E21B 41/00: Equipment or details not covered by groups E21B15/00 - E21B40/00 - G05D 11/13: characterised by the use of electric means - E21B: EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS - G05D: SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES ## Abstract System and method for conducting enhanced oil recovery by establishing a plurality of stacked, alternating slugs of gas and liquid travelling downhole into a subterranean well. The system can include a buffer tank, a gas inlet, a gas outlet, and a liquid outlet. The system can further include a pressure control configured to maintain a specified pressure in gas within the buffer tank and a fluid dispensing system in fluid communication with the gas and liquid outlet of the buffer tank. ## Claims ### Claim 1 A system for conducting enhanced oil recovery by establishing a plurality of stacked, alternating slugs of gas and liquid travelling downhole into a subterranean well, the system comprising: a buffer tank including: a liquid inlet through which liquid is received from a liquids source into the buffer tank; a gas inlet through which gas is received from a pressured gas source into the buffer tank; a gas outlet in fluid communication with gas reservoired in the buffer tank; and a liquid outlet in fluid communication with liquid reservoired in the buffer tank; a pressure control configured to maintain a specified pressure in gas reservoired within the buffer tank, and wherein the pressured gas reservoired within the buffer tank exerts a corresponding pressure on liquid reservoired within the buffer tank; and a fluid dispensing system in fluid communication with the gas outlet and the liquid outlets of the buffer tank, the fluid dispensing system being controlled to deliver alternating slugs of gas and liquid to a subterranean wellhead and thereby establishing the plurality of stacked, alternating slugs of gas and liquid travelling downhole into the subterranean well. ### Claim 2 (depends on 1) The system of claim 1, wherein the liquid inlet receives liquid-phase fluid from a mixing tank, constituting a liquid source, into the buffer tank. ### Claim 3 (depends on 1) The system of claim 1, wherein the gas inlet receives gas-phase fluid from a gas compressor, constituting a pressured gas source, into the buffer tank. ### Claim 4 (depends on 1) The system of claim 1, wherein the fluid dispensing system further comprises a pressured gas open/closed valve through which pressured gas from the buffer tank flows to the subterranean wellhead, the gas open/closed valve controlled to: open and initiate gas flow from the buffer tank to the subterranean wellhead; and close and cease gas flow from the buffer tank to the subterranean wellhead. ### Claim 5 (depends on 1) The system of claim 1, wherein the fluid dispensing system further comprises a pressured liquid open/closed valve through which pressured liquid from the buffer tank flows to the subterranean wellhead, the liquid open/closed valve controlled to: open and initiate liquid flow from the buffer tank to the subterranean wellhead; and close and cease liquid flow from the buffer tank to the subterranean wellhead. ### Claim 6 (depends on 5) The system of claim 5, wherein the fluid dispensing system further comprises a pressured gas open/closed valve through which pressured gas from the buffer tank flows to the subterranean wellhead, the gas open/closed valve controlled to: open and initiate gas flow from the buffer tank to the subterranean wellhead; and close and cease gas flow from the buffer tank to the subterranean wellhead. ### Claim 7 (depends on 6) The system of claim 6, wherein the fluid dispensing system is controlled to transition from delivering a slug of gas from the buffer tank to a slug of liquid from the buffer tank by coordinated closure of the gas open/closed valve and opening of the liquid open/closed valve. ### Claim 8 (depends on 7) The system of claim 7, wherein the gas pressure of the gas slug at the gas open/closed valve immediately before transition from delivering a gas slug to delivering a liquid slug is substantially equal to the liquid pressure of the liquid slug at the liquid open/closed valve immediately after the transition in dependence on the gas pressure being applied on the liquid reservoired in the buffer tank. ### Claim 9 (depends on 8) The system of claim 8, wherein gas pressure is applied directly upon the liquid reservoired in the buffer tank by open contact of the gas on the liquid. ### Claim 10 (depends on 6) The system of claim 6, wherein the fluid dispensing system is controlled to transition from delivering a slug of liquid from the pressured buffer tank to a slug of gas from the buffer tank by coordinated closure of the liquid open/closed valve and opening of the gas open/closed valve. ### Claim 11 (depends on 10) The system of claim 10, wherein the liquid pressure of the liquid slug at the liquid open/closed valve immediately before transition from delivering a liquid slug to delivering a gas slug is substantially equal to the gas pressure of the gas slug at the gas open/closed valve immediately after the transition in dependence on the gas pressure being applied upon the liquid reservoired in the buffer tank. ### Claim 12 (depends on 11) The system of claim 11, wherein the gas pressure is applied directly upon the liquid reservoired in the buffer tank by open contact of the gas on the liquid. ### Claim 13 (depends on 6) The system of claim 6, wherein each of the gas open/closed valve and the liquid 13, open/closed valve is remotely actuable. ### Claim 14 (depends on 13) The system of claim 13, wherein control of the gas open/closed valve and the liquid open/closed valve to transition between delivery of gas slugs and liquid slugs is automated. ### Claim 15 (depends on 14) The system of claim 14, wherein alternation between the delivery of gas slugs and liquid slugs to establish a stacked column of alternating slugs in the subterranean well is controlled so that a weight of the liquid slugs contributes a downward force on the stacked column at a formation to be stimulated. ### Claim 16 (depends on 10) The system of claim 10, wherein the transition from delivering a slug of liquid from the pressured buffer tank to a slug of gas from the buffer tank by coordinated closure of the liquid open/closed valve and opening of the gas open/closed valve occurs in one second. ### Claim 17 (depends on 10) The system of claim 10, wherein the fluid dispensing system is controlled to deliver pressured gas from the buffer tank for between 15 and 100 seconds, thereby establishing a corresponding slug of gas travelling down the subterranean well. ### Claim 18 (depends on 10) The system of claim 10, wherein the fluid dispensing system is controlled to deliver pressured liquid from the buffer tank for between 5 and 15 seconds, thereby establishing a corresponding slug of liquid travelling down the subterranean well. ### Claim 19 (depends on 18) The system of claim 18, wherein the fluid dispensing system is controlled to deliver pressured gas from the buffer tank for between 15 and 100 seconds, thereby establishing a corresponding slug of gas travelling down the subterranean well. ### Claim 20 (depends on 19) The system of claim 19, wherein the slug of gas travelling down the subterranean well establishes a bubble-region between consecutive slugs of liquid travelling down the subterranean well.