基于连通性方法的油藏分层精细注水优化

Optimization of Fine Water Injection for Reservoir Stratification Based on Connectivity Method

井间连通性是油藏注水优化研究的重要依据,建立了新的井间连通性模型及分层精细注水自动优化方法。基于激波理论,以井间连通单元为对象建立了精确的前缘追踪方法进行饱和度计算,获得井点处各层油水两相产出动态;通过对油藏历史动态进行自动拟合反演连通模型参数,得到注采井间传导率、流量劈分和注水效率等信息,并以此为依据通过迭代计算对油藏进行分层动态配产配注自动优化设计,减少低效水驱方向流量,改善注采矛盾。应用算例显示,所建方法计算速度快,能够准确地进行饱和度追踪和产出动态计算,所得分层注水方案较好地实现了降水增油的效果,实际油藏优化后预测年增油近5×10~4 m^3,为油田注采方案实时优化提供了新思路。

Interwell connectivity was crucial basis for an optimized study of reservoir water injection.A new cross-well connectivity model and an automatic optimization method for fine water injection were established.Based on shock wave theory,an accurate front tracking method was established to calculate saturation,and the oil-water two-phase production dynamics of each layer at well point were obtained.By automatically fitting of reservoir history and retrieving the parameters of the connected model,the data such as interwell conductivity,flow splitting and water injection efficiency were obtained.On the basis of iterative calculation,the automatic optimization design of distribution and injection for stratified dynamic production allocation was carried out to reduce the direction flow of low efficiency water drive and to improve the contradiction between injection and production.The application example shows that the method is fast,can accurately track saturation and calculate output dynamics,and the result of stratified water injection can achieve the effect of precipitation and oil increase.After the actual reservoir is optimized,the annual oil increase is nearly 5×10~4 m^3.It provides a new idea for real-time optimization of injection-production scheme in oilfields.