Study On Simulation Of Multi-stage Fracturing Horizontal For Shale Gas Well

As a clean energy, research for Shale gas mining technology has important strategic significance for China's energy structure adjustment. The aim is to optimize fracture half-length and spacing in a multistage fracturing design and rational Optimize of complex fracture network distribution system after horizontal well staged fracturing forming. The fluid-structure coupling equations were derived by using the basic theorem of porous media flow and the fluid structure coupling theory. According to the established calculation model, field examples hydraulic fracturing wells was simulated in different state with the flow field parameters,and optimized fracturing parameters by factor analysis. According to the similarity principle dynamic physics simulation, low permeability gas reservoir of flow mechanism was verified. The aim is to build a shale gas reservoir parameters dynamic variation and simulate seepage law for providing the basis for shale gas development program. The main research results are followed:(1) Based on the physical properties of stored state and seepage laws,shale gas content was deduced by the ideal gas equation and Langmuir isotherm equation.(2) Based on a series of basic assumptions of gas migration, the equation of gas migration which was considered the principle of conservation of mass, the Darcy flow, the non-Darcy flow is derived and the fluid flow of the matrix, porosity, fractures was analyzed.(3) Based on single factor analysis, the transport characteristics of shale gas under different conditions were studied. At a given pressure, initial conditions and boundary conditions and the number of artificial fracture was three, artificial fracture length and fracture spacing was fixed, the pore pressure changes was simulated. The pore pressure of gas reservoir variation was simulated and analyzed. Pore pressure of the matrix and fracture and fractures was research. The higher initial gas production and gas production fast fading late reason was explained. In the case of the fracture half-length was identical and the fracture spacing was different, the fracture spacing impact of gas production was simulated and analyzed. The optimal fracturing spacing was obtained; In the case of the fracture spacing was identical and the fracture half-length was different, the fracture half-length impact of gas production was simulated and analyzed. the optimal fracturing half-length was obtained; In the case of horizontal well length and fracture half-length was identical, number of fracture was 3-10 and hydraulic fracture was uniformly distributed, the number of fracture impact on gas production was simulated and analyzed. The optimal number of fracture was obtained;(4) Based on multivariate analysis, the fracturing parameters was counted. The influence and interference extent of number of fracture stages, fracture spacing and fracture half-length on the gas production was researched. Fracturing parameters and gas production were analyzed by using factor analysis. Sorted according to accumulated contribution rate of cumulative gas production, the cumulative gas production factors impact was quantitative analyzed.