Method for improving effective modification volume through refracturing of shale gas horizontal well

Abstract

The invention discloses a method for improving the effective modification volume through refracturing of a shale gas horizontal well. The method comprises the steps that (1) reservoir assessment is carried out before refracturing; (2) the position of a refracturing partial pressure segment cluster is confirmed; (3) a partial pressure method is selected; (4) activated water is injected to make up formation pressure; (5) low-viscosity slickwater seam expansion is carried out; (6) low-viscosity slickwater and small-particle-size supporting agent sand carrying is carried out; (7) the high-viscosity slickwater foam liquid construction stage is carried out; and (8) other processes of replacement, drilling and plugging, liquid drainage, production and the like are carried out. According to the method, reliable bases are provided for refracturing construction design of a shale gas pool. Refracturing construction of the shale gas pool can be effectively guided, the modification volume can be greatly increased, the construction efficiency can be obviously improved, and therefore the maximum economic benefits are obtained.

Description

technical field [0001] The invention relates to the technical field of petroleum exploitation, and more particularly relates to a method for increasing the effective volume of stimulation through repeated fracturing of a shale gas horizontal well. Background technique [0002] At present, the staged fracturing technology of shale gas horizontal wells has made a major breakthrough in China's marine high-pressure blocks, but as the production time progresses, the production decline is becoming more and more obvious. According to the current oil price level, when a single When the daily output of the well is less than 60,000 cubic meters, it may not be considered to have economic mining value. At this point, it is necessary to perform refracturing to slow down production decline and increase recovery. [0003] In a narrow sense, the refracturing technology of shale gas horizontal wells is to perform fracturing again in the same well and in the same layer. In a broad sense, re-...

AI Technical Summary

Problems solved by technology

[0005] 1) The production of two adjacent fractures produces a pressure relief effect, and the formation pressure will decrease relatively. Therefore, the fracture creation efficiency of the fracturing fluid is low, and the net pressure of the fracture is difficult to increase quickly;

[0006] 2) Due to the inhomogeneous production of two adjacent fractures, the azimuth of the in-situ stress may change while the magnitude of the in-situ stress decreases, and this azimuth change is uncertain

[0008] 1) The formation pressure deficit is larger, the filtration loss of fracturing fluid is larger, and the net pressure of fractures is more difficult to effectively establish and increase;

[0009] 2) It is not known whether the old fractures are extended or the new fractures are cracked again. Therefore, it is difficult to strengthen the pertinence of fracturing

The optimization technology of refracturing and refilling is mainly studied from the mechanism, and the specific process method is not involved