A method for increasing the complexity of the fracture network through cyclic stress fracturing

Abstract

The invention provides a method for improving the seam net complexity through circulation stress fracturing. By aiming at a sand-mud interbedding developing compact reservoir, the reservoir longitudinal stress feature study is firstly started; concrete reservoir ground stress factors influencing the seam expansion are clarified; then, the influence of the circulation stress fracturing on the seam net expansion is studied; and concrete circulation pump injection parameters are optimized. Through the study on the reservoir longitudinal stress distribution and the stress circulation rock fracture experiment study, the sand-mud interbedding developing compact reservoir is discovered; through the circulation pump injection fracturing, the complicated rock shearing damage can be generated, so that the seam net complexity degree is very complicated; the breakthrough of a plurality of sand-mud stress shielding layers in the longitudinal direction can be realized, so that a plurality of thin inter-oil layers in the longitudinal direction can be sufficiently transformed; and a more complicated seam net system is formed in the transverse direction. Compared with the early stage mixed water volume fracturing technology, the method has the advantage that the great improvement of single-well yield is facilitated.

Description

technical field [0001] The invention belongs to the technical field of tight oil reservoir transformation, and in particular relates to a method for increasing the complexity of fracture networks through cyclic stress fracturing. Background technique [0002] Tight oil reservoirs have tight reservoirs, fine pore throats, strong reservoir heterogeneity, well-developed natural fractures, and complex seepage characteristics of reservoirs. The concept of volume fracturing and its optimization method were adopted in the early stage. The idea is to comprehensively apply downhole microseismic technology to evaluate horizontal well volume fracturing fractures and volume fracturing simulation research to form a network of artificial fractures and natural fractures in the reservoir. system. [0003] However, with the further decline of tight oil quality, sand-mud interbeds are developed vertically in the oil layer, and muddy and calcareous interlayers are more developed in the layer....

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Problems solved by technology

[0003] However, with the further decline of tight oil quality, sand-mud interbeds are developed vertically in the oil layer, and muddy and calcareous interlayers are more developed in the layer. The single-stage oil layer is thinner, and the vertical characteristics are more complicated. It is difficult to fully produce the oil layers in each stage. , the increase in production is limited by the volumetric fracturing technology in the early stage

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