Research On Non-Linear Flow Law Of Micro-Nano Pores And Throat In Tight Reservoir

In China,the tight reservoir resources are large,but the pore throat radius is very small in the tight reservoir.And the understanding of conventional oil and gas flow law is no longer applicable.In the tight reservoir,the nonlinear flow and the interaction between solid and fluid cannot be ignored,which can cause microscale effect.In view of this problem,this paper carried out research on the flow law of micro-nano throat.Firstly,I used the Dissipative Particle Dynamics(DPD)method to simulate the fluid flow in the nano throat,from the micro display law of fluid flow in the nano throat.The flow law of nano throat is discussed on the basis of the boundary layer theory.The influence of boundary layer on the flow in the nano-throat road was analyzed by density field and velocity field,and the influence of the throat radius and pressure gradient on the flow.Secondly,in combination with DPD result and homogeneous channel flow experiment,analyzed micro-nano nonlinear characteristics and boundary layer thickness of pore throat characteristics.And discussed the pressure gradient,fluid viscosity and pipe radius on the influence of the flow and considering three factors of the boundary layer calculation formula is put forward.Finally,the effect of boundary layer on the distribution of effective pore throat radius is studied by using the boundary layer calculation formula,and the influence of boundary layer on effective pore throat is discussed.On this basis,the nonlinear flow equation is put forward.Through the study of this paper,it can effectively characterize the flow patterns of the fluid in the micro-nano pore throat,and explain the reasons for low permeability and difficult flow in tight reservoirs.The results of this paper provide some ideas for the development of tight reservoir,and it also plays a good role in enlightenment.