Effective Displacement Pressure System And Development Technique Of Ultra-low Permeability Reservoirs

Ultra-low permeability reservoir is difficult to development, the contradiction ofinjection-production become serious, it is hard to establish effective displacement pressuresystem(EDPS) between wells, so it is very necessary to find the corresponding developingtechnology policy. Thesis use reservoir engineering method analyzes the influencing factorsof well performance, assure the reasonable drown hole pressure. Based on work ahead, wedefined the concept of EDPS, and give the establish discriminant which included economicfactor and well productivity. Through the seepage mechanics and mirror image principle,ultra-low permeability EDPS of rectangular five\anti-nine-spot well network was deduced,made theoretical chart with production and other factors, analysis the lower bound of wellarray distance and permeability with EDPS. At last combined with the geology andexploitation characteristic of huaqing105area, establish geological model which considerstart-up pressure gradient, development technology policy is optimized. The result shows thateffective displacement pressure system has relationship with many factors, limit well spacingand row spacing are positively related to reservoir thickness and permeability, while followingoil viscosity increasing they will decrease. When the well spacing and row spacing are given,oil price and water cut change, permeability limits of extra-low permeability reservoir toestablish effective displacement pressure system will be different. The numerical simulationresearch result shows the optimum development technical technology of rectangular five-spotwell pattern in huaqing105area,the well spacing is400m, the row spacing is150m, theadvanced water injection time is three months, the pressure level is109%of the originalpressure, the injection-production is1.1,the produced fluid intension is2.5-3m3/d; and theoptimum development technical technology of reverse rhombus nine-spot well pattern isgiven, too. the well spacing is320m, the row spacing is150m, the advanced water injectiontime is four months, the pressure level is112%of the original pressure, theinjection-production is1.2,the produced fluid intension is2.5m3/d.The application example shows that the development effect of rectangular five-spot well pattern is better than reverserhombus nine-spot well pattern. The research result provides theoretical guidance forreasonably and effectively developing extra-low permeability reservoir.