Study On Evaluation Method Of Shale Gas Horizontal Well Productivity

Having been exploited for nearly one hundred years, the conventional oil and gas resources are going to be exhausted. As an important component part of unconventional resources and with the horizontal well fracturing technology being mature, shale gas resources have become a major field of gas exploration and production. Productivity evaluation is an important basis for reasonable gas well production and reasonable working system; it is the foundation of system analysis and production performance prediction, so the research on productivity evaluation of shale gas horizontal well is particularly important. In this paper, the productivity evaluation methods of shale gas horizontal well are obtained, which mainly includes the test data analysis method, the test data evaluation&empirical chart method, the numerical simulation method and the analytical method.Based on the knowledge of shale gas reservoir characteristics including its exploration&development situation, geological characteristics, typical well drainage conditions, production characteristics and the research of shale gas accumulation mechanism, adsorption&desorption mechanism, diffusion mechanism, flow mechanism, the main work that was completed is as follows:improved the test data analysis method, established the shale gas fracturing vertical well steady percolation model and shale gas equivalent fracturing horizontal well steady percolation model, established an improvement single point method of shale gas reservoir, pointed out that the binomial productivity evaluation, exponential productivity evaluation and single point method can be applied to shale gas well, researched the setting and transformation&calculation of pseudo pressure; researched the test data evaluation&empirical chart method; the numerical simulation method was studied using Eclipse; established the shale gas fracturing horizontal well unsteady percolation model, combined with the Matlab program, the analytical method was researched.Using the test data analysis method, test data evaluation&empirical chart method and numerical simulation method, the productivity of shale gas horizontal well was evaluated. Combined with the analytical method, the pressure dynamic characteristics and productivity dynamic characteristics of shale gas fracturing horizontal well was researched, the influence factors of productivity was analysised which indicated that the number of fracture, dimensionless fracture spacing, dimensionless wellbore storage ratio, desorption coefficient, dimensionless storability ratio, dimensionless desorption time and skin factor all have different influence on the productivity and pressure. Based on the Eclipse numerical simulation software, the effect of fracturing, desorption and diffusion on productivity of the typical characteristics of shale gas fracturing horizontal well was comprehensively analysised.The research of this paper concluded and developed the method of productivity evaluation of shale gas horizontal well, offerred some theoretical foundation and technical support for productivity evaluation of target shale gas reservoir horizontal well, it will had important referential significance for the same gas well, especially the productivity evaluation of shale gas fracturing horizontal well.