Shale gas front complex seam net constructing and fracturing technology

Abstract

The invention discloses a shale gas front complex seam net constructing and fracturing technology. The technology comprises the flows that a fracturing channel is opened; front seam making pretreatment liquid is pumped; micro cracks are made; main branch cracks are made; the front seam making pretreatment liquid is pumped; the micro cracks are made; the main branch cracks are made; main cracks aremade; and displacing liquid is pumped. By pumping the front seam making pretreatment liquid to reservoir stratums, the seam net complexity of the reservoir stratums is enlarged, thus a seam nut is complicated in advance, and the gas producing rate and the accumulative output are increased. Along with the front seam making pretreatment liquid pushed into the deep portions of the stratums, as shaleof the reservoir stratums is hydrophilic, the displacement effect is generated on associated gas and adsorbed gas among the reservoir stratums and seams, and the gas production rate and the yield arefurther increased. After the front seam making pretreatment liquid is pumped, cracking is carried out in time, the situation that a high-pressure liquid shielding area formed by pumping the front seam making pretreatment liquid disappears due to permeation and dispersion of the liquid can be prevented, the cracking time of each reservoir stratum is saved, in addition, excessive hydration expansion can be prevented, and pollution to the reservoir stratums is avoided.

Description

technical field [0001] The invention relates to the field of development of unconventional oil and gas reservoirs, in particular to a fracturing technology for constructing complex fracture networks in front of shale gas. Background technique [0002] At present, hydraulic fracturing technology is the key technology for the efficient development of shale gas reserves, and the most critical indicators of the 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 fracture network, the larger the volume of the fracture network, the better the development effect, and the higher the production in the later stage. Therefore, increasing the complexity of the fracture network and the volume of the fracture network in shale reservoirs is the key to improving the productivity of a single well. However, the fractures caused by the existi...

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