Research On The Integrated Optimization Model And Methodology For Water-control Completion In Horizontal Wells

Water control completion technology is proposed to solve the problem of premature water breakthrough in the horizontal wells.For the application of this technology,the horizontal wells should be divided into several segmentations.The effect of this technology depends on the design of completion plan.Based on the comprehension investigation and analysis of relevant research results at home and abroad,focusing on the problems such as poor segmentation plan and difficult design for completion plan in the application of horizontal well water control completion technology,this study has carried out systematic research as following by combining theoretical analysis and numerical simulation:(1)On the basis of dynamic contact angle theory,minimum energy method,two fluid model,homogeneous flow model,mass conservation law and momentum theorem,the oil-water two-phase flow model in horizontal wells is established by considering the effects of dispersed phase holdup and oil-water interface shape comprehensively.Based on the dimensional harmony theory and regression analysis method,the AICD pressure drop model is proposed by taking the influence of different factors into consideration.Combined the above two models with reservoir seepage model and skin factor model,a coupled flow model for the whole process of horizontal well water control completion is established.(2)The segmentation problem of horizontal wells water control completion can be divided into two categories:the first one is that distribution of reservoir physical properties(such as permeability)is known,and the second one is that distribution of reservoir physical properties(such as permeability)is unknown or not clear.In order to solve these two problems,an ordered clustering segmentation method is proposed based on permeability distribution of the whole flow region;on the basis of SPSA algorithm and the idea of robust control,the optimization segmentation method and uncertainty segmentation method are established for achieving highest cumulative oil production and the most balanced inflow profile.These three segmentation methods are compared with the uniform segmentation methods and the advantages and disadvantages of the three segmentation methods are discussed.(3)The overall optimization problem of horizontal well water control completion includes:well location optimization,AICD number optimization and AICD strength optimization.Among them,the AICD number optimization belongs to a typical 0-1 integer programming problem;the other two problems belong to multi parameter nonlinear optimization problems.Based on the idea of implicit enumeration method,a fast optimization method of AICD number is proposed by considering the water control mechanism of AICD;On the basis of SPSA algorithm and taking maximum cumulative oil production as the optimization objective,the well location optimization method and AICD strength optimization method are established respectively.Combining the above three methods,an overall optimization method for water control completion of horizontal wells is formed,which solves the optimization problem of water control completion of horizontal wells under the condition of well pattern.