M气田平湖组P4层气藏气水界面确定及储量计算

Determination of GWC and Estimation of Gas Reserves of P4 Reservoir of Pinghu Formation in M Gasfield

海上气田开发过程中,受限于作业成本,通常用于评价新构造的探井和开发井均较少,往往会出现无井钻遇气水界面的情况,导致静态地质储量评价存在一定不确定性,随着开发的持续,动态储量与静态地质储量有时会存在明显差异。根据岩心压汞实验分析结果,采用毛细管压力J函数,建立了地层条件下不同气柱高度与含水饱和度的关系,确定了M气田平湖组P4层气藏的气柱高度,并计算了气藏静态地质储量,计算结果与采用物质平衡法计算的动态储量较为接近。此外,根据新的储量计算结果更新了气藏地质模型,通过模型计算得出井底压力与实测井底压力的接近程度较高,模型预测的地质储量与实际生产井的动态储量较为接近,证明此方法具有一定的适用性。

Constrained by operation cost in the process of offshore gas field development,it is a common case that only a few exploratory and development wells are drilled for evaluating new structures.This often leads to the situation that no well is drilled into the gas⁃water contact(GWC),and consequently some uncertainties in the estimation of static geological reserves,and obvious differences between dynam⁃ic and static geological reserves with the development going on and more production data collected.Based on mercury injection experi⁃ments on special cores,the relationship between water saturation and gas column height under formation conditions is established by using the capillary pressure J function,then the gas column height in the P4 reservoir of Pinghu formation in M gasfield is calculated,and finally the static geological reserves are estimated again.The results are basically consistent with the dynamic reserves calculated using the materi⁃al balance method.In addition,the geological model of the gas field is updated according to the new understanding.The modelled BHP is well consistent with the measured BHP,indicating the good agreement between predicted and estimated geological reserves.The method proposed in the paper is applicable to some extent.