Completion Method And Application Research Of Shale Gas Reservoir In Southern Sichuan

The reserves of Qiongzhusi and Longmaxi reservoirs in South Sichuan are huge, and the potential economic value is high. But the relative lack of experience in shale gas reservoir fracturing, and the poor physical properties hindered the development and utilization of shale gas resources in South Sichuan.Based on the investigation of geological data, core X diffraction analysis, scanning electron microscope analysis, permeability and porosity experiment, the physical characteristics of shale gas reservoirs in South Sichuan are understood. Shale gas reservoir in South Sichuan is extremely dense, compared with the mature shale gas reservoirs in North America, its porosity and permeability are relatively low. But the content of silica in the mineral composition is higher, and it indicates that the brittleness index of the reservoir is higher. These show that shale gas reservoirs in South Sichuan have good potential for fracturing.Analysing lithology and physical property parameters and ground stress of three axis experiment and well logging images, the compressive strength, Young's modulus and Poisson's ratio of the reservoir are obtained. Logging interpretation shows reservoir is dense, brittle, low porosity and poor permeability, reservoir effective porosity is very small. The effective storage space of the reservoir is mainly concentrated in the fractured free gas and adsorbed gas.The core damage experiment was carried out. From the core of the water absorption characteristics, the results of the fracture expansion experiment the reasons for the low rate of the fracturing fluid after fracturing was found. At the same time, the results of crack expansion and stress sensitivity experiment also showed why the fracturing effect is not obvious.According to the optimization theory of shale completion, the research of basic experiment and the supplement of well logging interpretation, this paper recommends the well completion method of horizontal well and multi layer hydraulic fracturing in the south of Sichuan. On the one hand, the applicability of this kind of completion method is affirmed, on the one hand, it also presents some factors that influence the completion effect. The calculation and analysis of shale gas well completion optimization software provides a basis for further improvement of well completion design.