Study On Invertion Method Of Reservoir Interwell Dynamic Connectivity

During the oil field development, reservoir connectivity is not only important content of reservoir evaluation but also the basement of development and management program. In water injection projects, a knowledge of reservoir connectivity is particularly important to maximize oil recovery. As the development of reservoir, reservoir characteristics has changed a lot and the static state connectivity can't reflect layer property correctly.Work of dynamical interwell connectivity present prominent theory value and practical sense.Multivariate linear regression model(MLR) and capacitance model were built up with dynamic data of injection-production well, based on multivariate linear regression, reservoir simulation, signal processing and system analysis. Quantitative characterization reasearch on reservoir interwell dynamic connectivity was done in this paper. Influencing factors of time lag and attenuation law were discussed. Nonlinear diffusivity filter and first-order linear system method were introduced in MLR model. Parameters reprensent the degree of dynamic connectivity, the time lag and attenuation of injected signal were obtained. Both of the models wre validated through inverting intewell dynamic connectivity for several kinds of syfield models, including homogeneity reservoir, anisotropy reservoir, etc. Then this technology was applied to the dynamic connectivity analysis of reservoir J2x4 in Lu liang oil field.Research on injected signal time lag and attenuation indicates that the predominately influential factor of injected signal time lag and attenuation is well spacing, crude oil viscosity, total compressibility, porosity, permeatbility, formation plane anisotropic, effective thickness. Invertion of reservoir interwell dynamic connectivity shows that Multivariate linear regression model can only invert the connectivity in the case of stable Bottom-hole pressure(BHP), the improved model can obtain time constant and parameter representing time lag and attenuation through the filter and convolver. The capacitance model has several additional advantages: can be applied to fields in which wells are shut in; has the capability to incorperate BHP to enchance the investigation about well connectivity. And it also could obtain parameters that explicitly indicat the time lag and attenuation between injector and producer pairs. The research result indicates that the connectivity between wells is described by coefficients that only depend on geology characteristic, reservoir physical property and relative position between wells; they are independent of injection and production rates.