杏南开发区含钙特低渗透储层井网层系优化数值模拟研究

Numerical Simulation Study of Well Pattern and Layer Series Optimization in Extra-low Permeability Reservoirs Bearing Calcium of Xingnan Development Area

杏南开发区储层包括含钙特低渗透储层、表外储层和表内储层。其沉积环境复杂,油层之间的岩石物性相差较大,开发后动用状况复杂,剩余油分布高度零散,调整挖潜难度大。依据杏南开发区含钙特低渗透储层发育特征和注水开发动态特点,结合目前区块剩余油分布,研究层系组合和加密调整对开发效果的影响,为进行注采系统调整提供依据。针对杏南开发区的特点,首先设计了层系与井网井距相结合的部署方案,层系设计包括:射开含钙特低渗透储层和表外储层;射开含钙特低渗透储层、表外储层和有效厚度小于0.5m的表内层;射开含钙特低渗透储层和所有油层。将3套层系与4种井网、井距情况相结合,组合为12套方案,进行开发指标预测方案优选。结合经济评价认为,方案3为最优方案,即在原井网排间分流线位置布采油井,原井网采油井全部转注,新老井共同组成注采井距150m线状注水井网,射开含钙特低渗透储层和所有油层。

There are three types of reservoirs in Xingnan development area:extra-low permeability reservoirs bearing calcium,untabulated reservoirs and tabulated reservoirs.It has complicated sedimentary environment and large differences among rock physical property of oil layers.After development,it is difficult to tap the potential for complicated produced situation and scattered remaining oil distribution.According to growth characteristics and water flooding dynamic features of Xingnan extra-low permeability reservoirs bearing calcium,the influence of strata combination and infilling adjustment on development effect is studied combined with the existing remaining oil distribution of the block,which will provide the basis for injection-production system adjustment.Aiming at the characteristics of Xingnan development area,12 sets of combination schemes combining three series of layers with four kinds of well patterns or well spacing are designed,thus development index forecasting schemes are optimized.Three sets of series of layers will be perforated:extra-low permeability reservoirs bearing calcium and untabulated reservoirs;extra-low permeability reservoirs bearing calcium and untabulated reservoirs and tabulated reservoirs with less than 0.5m of effective thickness;and extra-low permeability reservoirs bearing calcium and all oil layers.Combined with the economic evaluation,we know that the scheme three is the optimal,and that is to say,new production wells should be drilled in fluid diversion line position between previous well pattern or well spacing,and the production wells of previous well pattern are all converted into water injection wells.New wells together with old wells constitute linear water injection pattern with well spacing of 150m.Extra-low permeability reservoirs bearing calcium and all oil layers should be perforated.