Research On Oil Stimulation Mechanism And Its Application Technology Under Different Development Conditions In Low Permeability Reservoir

With the exploitation of low permeability reservoir,a large number of problems emerge.In the initial stage of production,the oil block is in low water-cut stage,the exploitation depends on the natural energy and oil well production rate is high.With the development of oilfield,oil well production rate and formation pressure decrease rapidly.To complement the formation energy,oilfield adopts water-flooding with the increasing of block water-cut,especially in the middle and high water-cut stage,oil well rate remains in a low level,and the water injection rate drops down rapidly.To solve the problems mentioned above,this thesis puts forward the following solutions:This thesis takes A block in Jidong oilfield as an example to summarize the static and dynamic data.The technology of advanced water injection is put forward to solve the problem that the production rate of oil wells and the formation pressure decrease rapidly in low watercut stage.In order to study the low permeability oilfield oil stimulation mechanism of advanced water injection,a mechanism model of advanced water injection is established based on reservoir numerical simulation by respectively studying the effect of different well patterns,injection time,formation permeability,well spacing,row spacing for advanced water injection.Based on analytic hierarchy process and orthogonal experimental design principle,this thesis has put forward an optimal method considering multiple factors and targets and takes Jidong oilfield as an example to determine the optimal advanced water injection development policy.With the development of the low permeability oilfield in middle and high water-cut stage,reservoir heterogeneity is enhanced,the oil production declines and water injection becomes difficult.The fracturing of low permeability reservoir is a good way to solve the problem.In order to study the oil stimulation mechanism by fracturing the low permeability oilfield in middle and high water-cut stage,the mechanism model of fracturing is established based on reservoir numerical simulation by respectively studying the effect of different fracturing wells,formation permeability,fracture conductivity,half fracture length.Based on the optimization method mentioned above,this thesis takes Jidong oilfield as an example to determine the optimal fracturing development policy.In the paper,it reveals that in order to improve the development effect of low permeability oilfield,it is feasible to carry out advanced water-flooding in low water-cut stage and fraturing in middle and high water-cut stage.The research of the thesis provides a reference for the development of similar oilfields.