	US 11,725,492 B2
	Method to generate microfractures by chemical reaction in low carbonate mineral content shale reservoirs
Qiang Chen, Sichuan (CN); and James J. Sheng, Lubbock, TX (US)
Assigned to Texas Tech University System, Lubbock, TX (US)
Filed by TEXAS TECH UNIVERSITY SYSTEM, Lubbock, TX (US)
Filed on Jun. 7, 2019, as Appl. No. 16/435,178.
Claims priority of provisional application 62/681,826, filed on Jun. 7, 2018.
Prior Publication US 2019/0376376 A1, Dec. 12, 2019
Int. Cl. E21B 43/27 (2006.01); E21B 43/28 (2006.01); E21B 43/26 (2006.01); C09K 8/62 (2006.01); C09K 8/66 (2006.01)

CPC E21B 43/27 (2020.05) [C09K 8/665 (2013.01)]

20 Claims

1. A method comprising:

(a) selecting a well in a shale reservoir formation, wherein the well has a wellbore that is in operative fluid communication with the shale reservoir formation;

(b) pumping fluids under pressure down the wellbore of the well to hydraulically fracture the shale reservoir formation, wherein,

(i) all of the fluids pumped under pressure into the shale reservoir formation during the step of pumping the fluids are fracturing fluid, wherein

(A) the fracturing fluid was made by adding a content of sulfate acid or persulfate compound material to an aqueous solution,

(B) the sulfate acid or persulfate compound material is selected from a group consisting of (I) sulfate acids, (II) persulfate compounds, and (III) combinations thereof, and

(C) the content of the sulfate acid or persulfate compound material that was added to the aqueous solution is at least 1 wt. % of the fracturing fluid

(ii) an overall amount of the fluids are pumped under pressure into the shale reservoir formation during the step of pumping the fluids, and

(iii) the concentration of the sulfate acid or persulfate compound material is at least 1 wt. % of the overall amount of the fluids pumped under pressure into the shale reservoir formation during the step of pumping the fluids;

(d) producing hydrocarbons from the shale reservoir formation through the wellbore.