US 12,227,698 B2
Method of multi-stage fracturing of subterranean formation and slurry for that method
Thomas L Robl, Sadieville, KY (US); Anne Oberlink, Lexington, KY (US); Robert Jewell, Lexington, KY (US); Tristana Duvallett, Lexington, KY (US); Lance Cook, Houston, TX (US); and Lev Ring, Bellaire, TX (US)
Assigned to University of Kentucky Research Foundation, Lexington, KY (US)
Appl. No. 18/006,193
Filed by UNIVERSITY OF KENTUCKY RESEARCH FOUNDATION, Lexington, KY (US)
PCT Filed Jul. 26, 2021, PCT No. PCT/US2021/043147
§ 371(c)(1), (2) Date Jan. 20, 2023,
PCT Pub. No. WO2022/020799, PCT Pub. Date Jan. 27, 2022.
Claims priority of provisional application 63/055,971, filed on Jul. 24, 2020.
Prior Publication US 2023/0257646 A1, Aug. 17, 2023
Int. Cl. C09K 8/80 (2006.01); E21B 43/267 (2006.01)
CPC C09K 8/80 (2013.01) [E21B 43/267 (2013.01)] 13 Claims
OG exemplary drawing
 
1. A method of hydraulic fracturing of a subterranean formation having a well bore, comprising: injecting into the well bore a first slurry containing a first proppant at sufficiently high pressures to fracture the subterranean formation to accept the first slurry, wherein the first proppant is coal combustion fly ash particles that have a mean particle size (d50) of about 6 to 8 microns (μm);
after the injecting of the first proppant, injecting into the well bore a second slurry containing a second proppant at sufficiently high pressures to fracture the subterranean formation to accept the second slurry, wherein the second proppant is coal combustion fly ash particles that have a mean particle size (d50) of about 25-35 μm; and
after the injecting of the second proppant, injecting into the well bore (a) a third slurry containing a third proppant at sufficiently high pressures to fracture the subterranean formation to accept the third slurry, wherein the third proppant is coal combustion fly ash particles that have a mean particle size (d50) of 70 to 80 μm or (b) a mixture of the third proppant and fracking sand.