Fracturing transformation technology suitable for high steep structural coal bed

Abstract

The invention belongs to the technical field of coal bed fracturing transformation, and particularly relates to a fracturing transformation technology suitable for a high steep structural coal bed. The fracturing transformation technology comprises the following steps that A, pumping of prepad fluid is conducted, specifically, the prepad fluid comprises a prepad fluid propping agent and prepad fluid fracturing fluid, the prepad fluid propping agent is made of 70-100 meshes of quartz powder sand, and the prepad fluid fracturing fluid is activated water fracturing fluid; B, pumping of sand-carrying fluid is conducted, specifically, an earlier-stage sand-carrying fluid propping agent is made of 40-70 meshes of low-density fine sand, and earlier-stage sand-carrying fluid fracturing fluid is activated water fracturing fluid; a later-stage sand-carrying fluid propping agent is made of 20-40 meshes of quartz medium sand, and later-stage sand-carrying fluid fracturing fluid comprises linear gel fracturing fluid and bio-enzyme low temperature gel breaker; and C, pumping of displacement fluid is conducted, specifically, the displacement fluid is activated water fracturing fluid. According to the fracturing transformation technology suitable for the high steep structural coal bed, a combination technology of a particle size variable propping agent and a combination technology of the activated water fracturing fluid and the linear gel fracturing fluid are adopted, the problems that the high steep coal bed is prone to plugging sand in the fracturing process, the semi-diameter of a propping fracture is short, and coal bed transformation is not sufficient are solved, and the gas production rate of a coal-bed gas well is increased.

Description

technical field [0001] The invention relates to a fracturing transformation technology suitable for high and steep structural coal seams, and belongs to the technical field of coal seam fracturing transformation. Background technique [0002] my country's coalbed methane development is still in the exploratory stage, and relevant theories and technologies are still immature. Because coal seams have the characteristics of low porosity, ultra-low permeability, and strong heterogeneity, only by artificial hydraulic fracturing technology can CBM wells improve the seepage channels of CBM in the wells to obtain industrial production capacity with mining value. In the south of my country, especially in the northwest of Guizhou, the coalbed methane resources contained in the underground coal seams are very rich. However, due to the tectonic movement in this area, a large number of high and steep structural coal seams have been formed, which makes the development of coalbed methane i...

AI Technical Summary

Problems solved by technology

However, for the fracturing of high-steep structural coal seams, due to the influence of gravity, high-density proppant mostly accumulates near the wellbore. If artificial hydraulic fracturing technology is applied to ordinary coal seams, the fracturing fluid will suffer serious fluid loss. Sand plugging occurs, resulting in a short radius of propped fractures, which is not conducive to the effective support of secondary fractures, making the effect of coal seam fracturing reconstruction unsatisfactory