Study On Well Test Method For Horizontal Wells Of Shale Gas Reservoirs

Shale gas has aroused huge attention among governments and energy companies because of its tremendous resource potential. In recent years, the development technique based on horizontal well and hydraulic fracturing is improved greatly in the process of shale gas reservoir development, at the same time, the scholars pay more and more attention to the research of shale gas seepage rule, for its difference with conventional natural gas reservoir and its huge difficulty to development.The object of this article is to study the seepage mechanism and well test analysis. With the combination of modern fluid mechanics in porous medium, well test analysis, mathematic physics, computer programming and other subjects knowledge, in the condition of different media, this article makes a series of researches on unstable seepage theory of multi-fracturing horizontal well and well test analysis methods.The main works accomplished in this article are as follows:(1) Based on the extensive research on domestic and foreign literature, the shale gas reservoir characteristics, micro-flow characteristics and accumulative characteristics are studied, the shale gas desorption and diffusion migration mechanism are summarized, the output characteristics between conventional natural gas and shale gas are compared.(2) Starting from the seepage principle of shale gas reservoir, considering the effect of desorption and diffusion, with the utilization of principle of mass conservation, Darcy’s law, Langmuir isothermal adsorption equation and Fick’s law, the unstable flow mathematical model of multi-fracturing horizontal well in single media shale gas reservoir has been established, the pressure response curves are drawn. The typical curve and the affect to the curve by relevant parameter are analysed.(3) The unstable flow mathematical model of multi-fracturing horizontal well in dual porosity media with quasi-stable fluid channeling and unstable fluid channeling is proposed. In the process of model simplification, the quasi-stable model considering the matrix system only exists diffusion, the unstable model considering the matrix system exists both diffusion and darcy flow. Solving the model with semi-analytical method, the typical curves and influence of relevant parameters to these curves are analysed.(4) The real test data are analyzed by well test models of shale reservoirs which are established in this article. The results verify the proposed well test interpretation theory and its applicability...