Development Technologies Of The Abnormal High Pressure Ultra-low Permeability Reservoirs

In recent years, ultra-low permeability reserves take a high proportion during the explored reserves and unused reserves in China, and more and more ultra-low permeability oil fields are on production. As a special type of ultra-low permeability reservoir, abnormal high pressure ultra-low permeability reservoir has its own characters on exploitation mechanism. To know the flow regulation and exploitation character correctly and make the development plan reasonably has important guidance meaning.In this paper, based on the laboratory core experiment, the characters of deformation, non-linear flow and two phase flow curves in abnormal high pressure ultra-low permeability reservoir are researched, and the forecasting model is built to describe the pressure sensitivity and pseudo start-up pressure gradient. Then step by step steady state replacement is applied, and numerical solution method is used to determine the performance variation of abnormal high pressure ultra-low permeability reservoir elastic development, the formula that can predict the natural depletion oil recovery of abnormal high pressure ultra-low permeability reservoir is built, which considers the start-up pressure gradient and pressure sensitivity, and the factors that affects the elastic development change regulation and development effectiveness are analyzed.Multi-phase flow mathematical model is built to consider non-linear flow and pressure sensitivity, and finite difference discrete method is built for this model, the well-grid flow equation that describes non-Darcy flow in ultra-low permeability reservoir is deduced, and the inherent classical black oil model is based to realize this simulation method. Based on the model verification and numerical simulation forecasting results, the pattern conFig.uration of abnormal high pressure ultra-low permeability reservoir development is optimized, the well line under different permeability reservoir and different injection/production pressure difference is well defined, and the optimal time for injection water energy is determined.Based on the actual data of abnormal high pressure ultra-low permeability reservoir in Yong 1 well zone, the elastic development variation and recovery are predicted, and the feasibility of elastic development is evaluated; combined with the research result of mechanism model, the injection development well pattern scenario is made, and the feasibility of injection development is determined with the final economic evaluation parameter.