窄条带状普通稠油油藏平面波及系数计算方法

A Method for Calculating the Areal Sweep Efficiency of Narrow Banded Ordinary Heavy Oil Reservoirs

为解决窄条带状普通稠油油藏的油藏工程设计和评价问题,基于流管法和油水两相非活塞式水驱油理论,建立了一套平面波及系数的计算方法。以渤海某窄条带状普通稠油油藏为例,利用该方法分析了稠油启动压力梯度、注采压差和采液强度对平面波及系数的影响。结果表明,原油黏度较大时,窄条带油藏边部存在无法动用的死油区,导致平面波及程度低,可通过提液、增大注采压差等方式提高注入水的波及程度。同时考虑到海上平台液处理能力的限制,计算得到了不同河道宽度油藏的采液强度界限,优化了生产井的合理产液量,指导油田生产井提液,平均单井日增油达15m^3/d,取得了较好的开发效果。研究成果对同类油藏的开发有借鉴意义。

In order to realize reservoir engineering design and evaluation of narrow banded conventional heavy oil reservoirs,a set of calculation methods for areal sweep efficiency were developed based on stream tube method and oil-water two-phase non-piston like displacement theory. These methods were applied to a certain narrow banded conventional heavy oil reservoir in Bohai Sea to analyze the effects of threshold pressure,injection/production pressure difference and liquid production per unit thickness on the areal sweep efficiency of heavy oil reservoir. It is indicated that when the oil viscosity is higher,there are dead oil areas at the edge of narrow banded oil reservoir,so the areal sweep efficiency is low. And the sweep efficiency of injected water can be increased by lifting the liquid or increasing the injection/production pressure difference. Meanwhile,considering the limited liquid processing capacity of offshore platform,the threshold liquid production per unit thickness was calculated for oil reservoirs with different channel width and the liquid production rate of production wells was optimized to guide its liquid lifting. Consequently,the development result is better with average incremental oil per well of 15m^3/d. The research results can be used as the reference for the development of similar oil reservoirs.