Fracturing technology for improving effective support of shale fracturing complex fracture network

Abstract

The invention discloses a fracturing technology for improving effective support of a shale fracturing complex fracture network. The fracturing technology comprises the following steps that (1) well cleanup is conducted; (2) perforation is conducted; (3) fracturing treatment is conducted, specifically, a suspension fluid formed by mixing a prepad fluid with 140-300 mesh quartz sand is pumped at thedisplacement of 10-12 m<3> / min firstly, then a sand-carrying fluid is pumped at the displacement of 10-12 m<3> / min, 70-140 mesh quartz sand is adopted as an early-period proppant of the sand-carryingfluid, 40-70 mesh ceramsite is adopted as a later-period proppant of the sand-carrying fluid, finally, a displacing fluid is pumped for displacement, and pumping is stopped after displacement; (4) segment treatment is conducted; and (5) the steps (2) and (3) are repeated, and next segment of fracturing operation is completed. According to the fracturing technology, a microfracture and a secondaryfracture network can be effectively supported, meanwhile, a fracturing major fracture and a branched fracture are also supported advantageously, finally, effective support of the shale complex fracture network is improved overall, the yield of shale gas is increased, and the successive decreasing speed of a shale gas well is decreased.

Description

technical field [0001] The invention belongs to the technical field of oil and gas stimulation and transformation, and in particular relates to a fracturing process for improving the effective support of complex fracture networks in shale fracturing. Background technique [0002] "Formation of complex fracture networks" is the main goal of shale gas stimulation and stimulation. Shale fracturing usually uses low-viscosity fluids to stimulate high-brittle shale reservoirs. Large displacement is beneficial to increase net pressure, and effective fracture sealing is adopted. The method causes the opening or turning of multiple fractures, and finally forms a complex fracture network system of "main fractures + branch fractures + micro-fractures". With the increasing understanding of shale fracturing, a secondary fracture network with a large number of branch fractures and micro-fractures will be generated in shale fracturing. These secondary fracture networks absorb up to 70%-90...

AI Technical Summary

Problems solved by technology

[0003] At present, the proppant used in shale gas fracturing is mainly used to support artificial main fractures, but it cannot play a good supporting role for micro-fractures and secondary fracture networks far away from the main hydraulic fractures. However, shale fracturing produces However, the development of micro-fractures and secondary fracture networks is extremely rich. If the potential of branch fractures and secondary networks of micro-fractures can be fully utilized to transform and expand the vast unswept reservoir volume, the complex fracture network of shale fracturing will be improved. Effective support can greatly increase effective fracture support and SRV, and has significant value in increasing the economic benefits and service life of shale gas wells

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