# US 12,180,415 B2 · Method of drilling a shale formation with a drilling fluid composition > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,180,415 B2 - Document ID: US12180415B2 - Status: Granted - Kind: B2 - Application number: 18/606,567 - Filed: 2024-03-15 - Published: 2024-11-14 - Granted: 2024-12-31 - Earliest claimed: 2023-05-11 - Assignees: King Fahd University of Petroleum and Minerals - Applicants: King Fahd University of Petroleum and Minerals - Inventors: Tawfik Abdo Saleh; Azeem Rana - Web page: https://patentgrep.com/patent/US12180415B2 ## CPC - C09K 8/18: characterised by the organic compounds - C09K 8/206: {Derivatives of other natural products, e.g. cellulose, starch, sugars} - E21B 43/16: Enhanced recovery methods for obtaining hydrocarbons - C09K 2208/08: Fiber-containing well treatment fluids - C09K 2208/10: Nanoparticle-containing well treatment fluids - C09K 2208/12: Swell inhibition, i.e. using additives to drilling or well treatment fluids for inhibiting clay or shale swelling or disintegrating - 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 drilling fluid composition includes an aqueous base fluid, 0.01 to 5 wt. % of polyamine-functionalized activated carbon (AC-PAD), 0.1 to 10 wt. % of a shale material, 0.01 to 2 wt. % of a thickener, 0.1 to 10 wt. % of a fluid loss control additive, 0.01 to 5 wt. % of an adsorbent, and 1 to 20 wt. % of a borehole stabilizer. Each wt. % is based on a total weight of the drilling fluid composition. The AC-PAD is uniformly disposed on surfaces of the shale material. The shale material has an average pore size of 5 to 400 nanometers (nm). A method of preparing the AC-PAD and a method of drilling a subterranean geological formation. ## Claims ### Claim 1 A method of drilling a shale formation, the method comprising: drilling the subterranean geological formation to form a wellbore therein; and injecting a drilling fluid composition into the wellbore during the drilling, wherein during the injecting the drilling fluid composition is circulated in the wellbore at a pressure that is higher than the static pressure of the shale formation: wherein the drilling fluid composition comprises: an aqueous base fluid; 0.01 to 5 wt. % of polyamine-functionalized activated carbon (AC-PAD); 0.1 to 10 wt. % of a shale material; 0.01 to 2 wt. % of a thickener; 0.1 to 10 wt. % of a fluid loss control additive; 0.01 to 5 wt. % of an adsorbent; and 1 to 20 wt. % of a borehole stabilizer; wherein each wt. % is based on a total weight of the drilling fluid composition; wherein the AC-PAD is uniformly disposed on surfaces of the shale material; and wherein the shale material has an average pore size of 5 to 400 nanometers (nm). ### Claim 2 (depends on 1) The method of claim 1, wherein the AC-PAD molecules in the drilling fluid composition are in the form of dendrimers having a plurality of at least one repeating unit selected from the group consisting of and wherein n is any integer from 1 to 100 inclusive. ### Claim 3 (depends on 1) The method of claim 1, wherein each of the AC-PAD molecules of the drilling fluid composition comprises a carboxylic acid-functionalized activated carbon core and a plurality of polyamidoamine branch structures, and wherein at least one carboxyl group of the activated carbon core is covalently bonded to at least one amine group of at least one of the polyamidoamine branch structures. ### Claim 4 (depends on 1) The method of claim 1, wherein the shale material of the drilling fluid composition comprises at least one clay selected from the group consisting of sodium bentonite, calcium bentonite, potassium bentonite, sodium montmorillonite, and calcium montmorillonite. ### Claim 5 (depends on 1) The method of claim 1, wherein the shale material of the drilling fluid composition comprises 50 to 65 wt. % kaolinite, 15 to 35 wt. % quartz, 5 to 15 wt. % muscovite, 1 to 8 wt. % microcline, 0.1 to 3 wt. % goethite, 0.1 to 3 wt. % gibbsite, and 1 to 10 wt. % illite based on the total weight of the shale material. ### Claim 6 (depends on 1) The method of claim 1, wherein the aqueous base fluid comprises one or more selected from the group consisting of a foaming agent, a gelling agent, a pH control agent, a breaker, an oxidizing breaker, a gel stabilizer, a clay stabilizer, a corrosion inhibitor, a crosslinking agent, a scale inhibitor, a catalyst, a preservative, a biocide, and a thermal stabilizer. ### Claim 7 (depends on 1) The method of claim 1, wherein the thickener of the drilling fluid composition comprises at least one selected from the group consisting of xanthan gum, guar gum, corn starch, gelatin, and a cellulosic thickener. ### Claim 8 (depends on 1) The method of claim 1, wherein the fluid loss control additive comprises at least one selected from the group consisting of lignite, cellulose, and hemicellulose. ### Claim 9 (depends on 1) The method of claim 1, wherein the adsorbent of the drilling fluid composition comprises poly aluminum chloride having a formula [Al2(OH)nCl6-n]m, wherein 1≤n≤5, and 0