The integrative research of 3D geological modeling and reservoir numerical simulation
With the rapid development of computer, the integration research of geological modeling and numerical simulation is more and more emphasized in oilfield. In this paper, the flow mathematical model is established, which considers starting up pressure gradient for low permeability reservoir. Based on the research of the geology characteristics, fine stratigraphic correlation and sedimentary facies, the 3D geological model is established through integrated research considering geology and reservoir, including facies model, oil saturation model, porosity model, permeability model and NTG model. Then the remaining oil distribution was calculated through fine reservoir simulation. Based on history match, the distribution of remaining oil is analysed through the research of deposition facies and flow layer, which can be used for reference on oilfield development potential adjustment and scheme design.
NON-DARCY SEEPAGE MODEL OF EXTRA-LOW PERMEABILITY OIL RESERVOIR AND ITS APPLICATION
According to the results of mine test and lab experiment,non-Darcy seepage flow will occur during the exploitation of reservoirs with low permeability and extra-low permeability,especially the crude oil seepage flow, which will have a obvious startup pressure gradient.Considering that the seepage flows of the oil and water have startup pressure gradients and that rock has stress sensibility,the three-dimensional oil-water two-phase mathematical model is built,and combined with the characteristics of the low permeability reservoir's water injection exploitation.The finite difference schemes of the seepage mathematical model are obtained by the finite difference method;and the numerical simulation software is developed.The numerical simulation results of the production history of Yuan 121 - 3 block of Zhaoyuan Oil Field in Daqing are compared and successively verified with the field production data.Based on the five-point injection-production well network,a square injection-production unit is designed.Under the condition of keeping bottom pressures of producer and injector wells constant,the space between the injection and the production well is changed:and the formation fluid pressure,fluid pressure gradient,formation absolute permeability,and the spatial distribution of the startup pressure gradient are obtained by using the numerical simulation software when oil well begins to produce water. At last,the effective space between the injection well and the production well is achieved to provide references to the network arrangement of the injection and production wells for the extra-low permeability reservoir.
The Use of Variable Weighting to Eliminate Numerical Diffusion in Two-Dimensional Two-Phase Flow in Porous Media
A simple numerical method has been developed that largely eliminates numerical diffusion errors associated with saturation discontinuities or shocks for two-phase flow in one and two dimensions. The important aspect of the approach is the computation of a variable weighting factor for the interface fractional flow between grid blocks. The approach appears to be generalizable to the multicomponent, multidimensional case including gravity and capilarity. 5 refs.