Shale gas pre-complex fracture network construction fracturing technology

Abstract

The invention discloses a fracturing technology for shale gas pre-complex fracture network construction. Place fracture-forming pretreatment fluid-create micro-fractures-create main branch fractures-create main fractures-pump displacement fluid, and by pumping pre-fracture-forming pretreatment fluid into the reservoir, expand the complexity of the fracture network of the reservoir and make the reservoir more complex. The fracture network is complicated in advance, which increases the gas production rate and cumulative production. As the pre-fracture pretreatment fluid is pushed into the deep formation, because the shale in the reservoir is hydrophilic, it will affect the associated gas and the interlayer fractures. Adsorbed gas produces displacement, which further improves gas production rate and production; after pumping pre-fracture pretreatment fluid, fracturing in time can prevent the high-pressure liquid barrier area formed by pre-fracture pretreatment fluid from being pumped. It disappears due to permeation and diffusion, saving the fracturing time of each layer of the reservoir; in addition, it can prevent excessive hydration expansion and avoid reservoir pollution.

Description

technical field [0001] The invention relates to the field of unconventional oil and gas reservoir development, in particular to a shale gas pre-complex fracture network construction fracturing technology. Background technique [0002] At present, hydraulic fracturing technology is the key technology for efficient development of shale gas reserves, and the most critical indicators of fracturing development effect are the complexity and volume of the fracture network formed during the fracturing process, and the fracture network formed during the fracturing process. The more complex, the larger the fracture network volume, the better the development effect, and the higher the later production. Therefore, improving the complexity and volume of the fracture network in the shale reservoir layer is the key to improving the productivity of a single well. However, the fractures caused by the current fracturing technology are relatively concentrated, and the fracture network is not c...

AI Technical Summary

Problems solved by technology

However, the fractures caused by the existing fracturing technology are relatively concentrated, and the fracture network is not complex, which affects the conductivity of the near-wellbore zone and restricts the improvement of gas production rate and production.

[0003] At present, there is also a technology for pretreatment of shale reservoirs to increase the complexity of the reservoir fracture network, but if the treatment time is too long, it will cause the seepage and diffusion of the liquid, making the plugging effect disappear, which is not conducive to the complexity of the fracture network, and Causes excessive hydration expansion, completely closes fractures and contaminates the formation

In addition, because shale gas often exists as associated gas and adsorbed gas, there is little free state, even after fracturing to form a fracture network, it is not easy to escape and overflow, and the stimulation effect is limited