Shale gas horizontal-well refracturing temporary-plugging critical pressure testing method

Abstract

The invention belongs to the technical field of unconventional oil and gas innovation for increasing output, and discloses a shale gas horizontal-well refracturing temporary-plugging critical pressure test method. The shale gas horizontal-well refracturing temporary-plugging critical pressure test method comprises the following steps that shale gas reservoir rock samples are collected, and the rock samples are cut into the same size specifications; geological parameters of the shale gas reservoir rock samples are collected, a pressure curve of initial fracturing construction of a shale gas well is analyzed, and closure pressure of a reservoir stratum is obtained; the rock samples are divided into three groups, each group of shale gas reservoir rock samples are overlaid according to upper, middle and lower layers, and quantitative temporary plugging additives are evenly laid between every two adjacent rock samples; the overlaid rock samples are connected with test pipelines, and displacement is conducted on temporary plugging overlaid rock sample created fractures by using slickwater; and effects of the different temporary plugging additives, the temporary plugging additive sealing and plugging lengths and the fracture widths on temporary plugging critical pressure are analyzed quantitatively. According to the shale gas horizontal well refracturing temporary plugging critical pressure test method, under the condition of formation effective closure stress, the temporary plugging critical pressure of different types and amounts of the temporary plugging additives on a hydraulic fracture can be tested conveniently, and reference standards for optimization selection and optimization design of the temporary plugging additives are provided.

Description

technical field [0001] The invention belongs to the technical field of unconventional oil and gas stimulation and transformation, and relates to a critical pressure test method for repeated fracturing of a shale gas horizontal well. Background technique [0002] Shale gas is an unconventional natural gas resource buried in extremely low porosity and permeability reservoirs. Volume fracturing is an effective technical means to realize its industrialized exploitation, especially in the development of shale gas in North America and China’s Sichuan Basin. . The practice of shale gas development in recent years shows that the reservoir pressure will continue to decay during the production process of shale gas wells, and the conductivity of reservoir fracture systems will also decrease with the increase of formation effective stress, causing a sharp decline in the production of shale gas wells, resulting in low production and low production. effect. In addition, mine production ...

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Problems solved by technology

[0004] At present, the existing technology has loopholes in the critical pressure test method for refracturing temporary plugging of shale gas horizontal wells, which cannot completely simulate the formation conditions, such as Patent No. Test method for temporary plugging rate of refracturing plugging agent", the above method ignores the closure pressure and formation temperature of refracture formation, this test method is calculated under the pressure balance condition, if the closure pressure is ignored, it will get wrong results ; Patent No. 106869892A "A Judgment Method for Temporary Plugging and Cracking in Refracturing Well Fractures" introduces a quantitative analysis method for judging temporary plugging and cracking in repeated fracturing, but has not established a simulation of the critical pressure of temporary plugging, and cannot determine the critical pressure of temporary plugging judge

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