五里湾长6油藏合理地层压力计算方法研究

Reasonable Calculation Method of Formation Pressure to Wuliwan Chang6 Reservoir

五里湾油藏属于典型的特低渗透油藏,而现有的通过典型曲线拟合得到的外推地层压力一直无法有效地反映真实的地层压力保持水平,经常出现通过拟合外推地层压力与油藏常识相违背情况。通过分析比较,研究了拟合外推地层压力、平均地层压力和压力恢复末点压力等八种地层压力用于反映地层压力保持水平的适用性,说明现用拟合外推地层压力不适用于特低渗透油藏一般情况的应用,提出的Kuchuk方法不受特低渗透油藏特征和邻井的影响,也不受流动期和生产时间长短的影响,对反映五里弯特低渗透油藏压力水平有较好的适应性。

Wuliwan reservoir belongs to a typical ultra-low permeability one,while,the existing extrapolation formation pressure obtained by the typical curve fitting has been unable to reflect the true formation pressure maintenance level effectively and situations are often appear such as extrapolation formation pressure is contrary to common sense of field reservoir knowledge. By analysis and comparison,eight pressure calculation methods,which are used to reflect the maintenance level of formation pressure,have been made,such as fitting extrapolation formation pressure method,average reservoir pressure method and end point pressure method,to illustrate that fitting extrapolation formation pressure method does not apply to the general case of ultra-low permeability reservoirs and the proposed Kuchuk method is not affected by ultra-low permeability reservoir characteristics and adjacent wells,also not subject to the flow period and the length of production time,which reflects that the formation pressure level for Wuliwan ultra-low permeability reservoir has a better adaptability.