低渗、特低渗油藏极限井距计算新方法

A New Method for Calculating the Limit Production-Injection Well Spacing in Low(Ultra-Low) Permeability Reservoir

克服低渗透油层启动压力梯度所需的最小驱替压力梯度所对应的注采井距,是注水井和生产井之间能够建立有效驱动压力系统的极限注采井距。采用一源一汇不等产量注采模型推导了注采井间主流线上驱替压力梯度的新公式。新民油田扶杨油藏属典型的低孔低渗油藏,结合该油藏实际开发特征计算出了注水井和生产井间能够建立有效驱动压力系统的极限井距,与常见的几种极限井距计算方法进行对比表明,该方法能较好地应用于油田实际。

The producer-injector spacing corresponding to the minimum displacement pressure gradient overcoming the start-up pressuregradient in low permeability reservoir is the limit well spacing for establishing effective displacement pressure system between producerand injector. According to producer-injector model of aniso-production one-source and one-convergence point, a new formula for displace-ment pressure gradient in main stream line between producer-injector is deduced and applied to Fuyang reservoir in Xinmin oilfield whichbelongs to a typical low porosity and low permeability reservoir. This paper takes account of the real status of the reservoir development anddetermines the limit well spacing for it by this new method. Comparing common calculation methods available, the result shows it can bewell applied in practice.