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US 3,933,205 AGranted
Hydraulic fracturing process using reverse flow
OwnerOthar Meade Kielinventor
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OwnerOthar Meade Kielinventor
Estimating the term…
Well productivity is increased by multiple hydraulic fracturing cycles. A double cycle first creates a long primary fracture by fluid injection and forms spalls by subsequently allowing the pressure in the fracture to drop below the initial fracturing pressure by discontinuing injection and shutting the well in or allowing it to flow back, resuming injection to displace said spalls longitudinally in said fracture and again discontinuing injection, whereupon the fracture is propped open by the displaced spalls. Multiple applications of this double cycle successively create transversely directed secondary long fractures. Fracture extension and fluid loss is controlled by the sandout of fine spalls at terminal ends of the fractures, supplemented when necessary by the injection of sand of selected size to filter pack the natural joint system and, in some instances, to filter pack the vertical downward extent of joints and fractures thus limiting further fractures to the upper portion of the producing formation where upward leakage is inhibited by the overburden.
A method of well treatment by hydraulic fracturing of the formation to be treated, said fracturing including at least one double cycle comprising injection of fluid into the formation for a period of at least three minutes under pressure throughout said period sufficient to fracture the formation;
Method according to 1 including two double cycles.
Method according to 1 including three double cycles.
Method according to 1 including a plurality of double cycles.
Method according to 1 incuding injecting fine sand with the fracturing fluid to limit the vertical conductive extent of the fracturing.
Method according to 1 including injecting fine sand for fluid loss control.
A method of well treatment by hydraulic fracturing of the formation to be treated, said fracturing including a plurality of double cycles each of which double cycle comprises:
Method according to 14 wherein the number of double cycles is two.
Method according to 14 wherein the number of double cycles is three.
Method according to 14 wherein the well is not produced between double cycles.
Method according to 14 wherein each period of said discontinuing injecting fracturing fluid, except the last such period, lasts for from 5 minutes to one hour.
Method according to 14 wherein the injection pressure during each double cycle subsequent to the first double cycle is significantly greater than during the first double cycle, i.e. is at least 10 percent greater.
Method according to 14 wherein the period of the even numbered injection is of the order 1/4 to 1/3 the period of the immediately preceding odd numbered injection, considering that the several injections are numbered consequently in chronological order.
Method of 14 wherein the periods of the several consecutive pairs of injection periods, considering the first and second injection periods as the first such pair are approximately proportional to the square root of the number of such pair, considering that the several pairs are numbered consecutively in chronological order.
Method according to 14 wherein the periods of discontinuance of injection and reverse flow, other than the last one, are such that the shut in pressure does not fall to less than 1/3 of the amount of the increase in pressure during the previous injection, thereby to avoid excessive fluid loss.
Method according to 14 wherein the fracturing fluid is of the formation pressure increasing type, i.e., if injection were at constant rate, the injection pressure measured at the well head initially increases.
Method of well treatment by hydraulic fracturing of the formation to be treated, said fracturing including at least one double cycle comprising
Method of well treatment by hydraulic fracturing of the formation to be treated, said fracturing including a plurality of double cycles each of which double cycle comprises:
Method of well treatment by hydraulic fracturing of the formation to be treated, said fracturing including at least one double cycle comprising:
Method of well treatment by hydraulic fracturing of the formation to be treated, said fracturing including at least one double cycle comprising:
Dependencies are inferred from the claim text.