Macro-scale Flow Simulation And Productivity Analysis In Shale Oil And Gas Reservoirs

In the new era of fuel energy transformation,“Horizontal well and Hydraulic fracturing” has made shale oil and gas become a new development hot spot.Due to the complex pores structure,various hydrocarbon storage forms and large span of porous media,the conventional flow theory has been unable to simulate the oil and gas flow in shale reservoirs accurately.Therefore,it is of great significance to establish a set of flow simulation methods considering the characteristics and development features of shale oil and gas reservoirs.In this dissertation,the macro-scale flow simulation and productivity analysis methods based on the micro-scale transport mechanisms of shale oil and gas is presented.Firstly,according to the mechanisms of oil and gas transport in micro-scale pores,we improve the existing theory and models,and establish the mathematical models of shale oil and gas transport in inorganic and organic porous media respectively based on the porous meida parameters(porosity and tortuosity).Besides,we reveal coupling transmission mechanisms of oil and gas transport in different types of shale porous media.Secondly,the coupling mathematical models of shale oil and gas apparent permeability are proposed by introducing the organic pores content.In addition,the influences of the micro-scale oil and gas transport mechanisms(viscous flow,Knudsen diffusion,surface diffusion,velocity slip and physical adsorption)on the shale oil and gas apparent permeability and the contributions of them to the shale oil and gas apparent permeability are analyzed.Thirdly,based on the elliptical SRV and the fractal SRV,the dual-porosity and single-permeability models for the vertically fractured wells(VFWs)in shale gas and oil reservoirs are developed.The influence factors of the pressure response and productivity of VFWs are analyzed,and the method for estimating SRV size based on the typcal curve of the VFW in shale reservoirs is presented.Meanwhile,based on the discrete fractured model(DFM)and apparent permeability models,the dual-porosity and dual-permeability models for the VFW in shale reserovirs with coupling the matrix-natural fractureshydraulic fractures are developed.The influence factors of the VFW productivity are analyzed and the results of analytical and numerical models are compared.The flow simulation and productivity analysis methods of VFW in shale reservoirs are presented.Fourthly,based on linear flow assumptions and point source function,the linear flow and composited flow dualporosity and single-permeabiltiy models for multistage fractured horizontal wells(MFHWs)in shale reservoirs are established.The influence factors of the pressure response and productivity of MFHWs are analyzed.Meanwhile,according to the DFM model and apparent permeability models,the dual-porosity and dual-permeability models for MFHWs in shale reserovirs including dual-porosity media model and composited reservoir model are proposed.The effects of the parameters of matrix,natural fractures,hydraulic fractures and SRV patterns on the MFHW productivity are studied,and the results of various models are compared.The flow simulation and productivity analysis methods of MFHWs in shale reservoirs are developed.Finally,based on the ES-MDA automatic history matching technique,the method of automatic history matching using the analytical flow models is presented.According to the field data and numerical flow models,the rate performance of different “multi-well pad” with coupling various well types and fractures networks is studied.The effective methods for the macro-scale flow simulation and productivity analysis of shale oil and gas are developed,which provides a theoretical guidance for the furtherly effective development of shale reservoirs.