Controllable impact-wave shale reservoir pre-fracturing method

Abstract

The invention discloses a controllable impact-wave shale reservoir pre-fracturing method. The controllable impact-wave shale reservoir pre-fracturing method comprises the following steps that 1, a reservoir section difficult to split is determined according to shale gas data, impact-wave parameters required by fracturing a reservoir are selected, and the impact times of each perforation cluster are designed; 2, a fracturing device capable of producing controllable impact waves is pushed to the perforation cluster position at the farthest end; 3, impact is carried out beginning from the perforation cluster at the farthest end, and after operation amount is completed at each perforation cluster position, the fracturing device is moved to a next perforation cluster position to be operated foroperation; 4, after controllable impact-wave operation is completed, a device is lifted out, and fracturing construction is performed. By adopting the controllable impact-wave shale reservoir pre-fracturing method, cracks can further extend under multiple times of impact effect, a crack net is formed around a well shaft, and fracturing pressure of a reservoir can be reduced or a reservoir difficult to fracture can be fractured open.

Description

technical field [0001] The invention belongs to the field of energy, and relates to a method for pre-cracking shale, in particular to a method for pre-cracking shale reservoirs with a controllable shock wave, which is applied to the exploitation of shale gas. Background technique [0002] Shale gas reservoir is a kind of matrix with very low permeability (generally less than 1×10 -3 μm 2 ), with a porosity of only 3% to 5%. What made a great contribution to the "shale gas revolution" in the United States is the free gas that exists in many micron to nanoscale matrix and organic pores. Therefore, shale formations need large-scale volume reconstruction to form complex fracture networks and improve permeability in shale formations to obtain industrial yields. [0003] Domestic shale gas development has reached the fracturing scale of Wanfangshui and Qianfangsha. The fracturing cost of shale formations accounts for 50-60% of the total cost of a single well, constituting the m...

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to provide a controllable shock wave pre-cracking method for shale reservoirs to supplement the deficiency of the traditional static pressure-based conventional technology. This method can make up for the lack of natural fractures or natural fractures without damaging the casing. The problem that underdeveloped reservoirs cannot be developed

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