牛圈湖油田储层潜在裂缝特征及注水开发对策

牛圈湖油田西山窑组油藏为低孔、低渗、低压油藏,油藏天然裂缝不发育,但部分油井投入注水开发后,初期就出现含水快速上升,甚至早期水淹的现象.运用示踪剂监测、脉冲试井及生产动态资料等方法分析目前油藏见水特征,认为研究区次生裂缝分布广泛,裂缝主要为超破压注水与人工压裂形成,且裂缝发育方向受区域最大主应力方向及油藏构造形态控制.通过实施堵水调剖,控制注水压力,转注主向水淹井,调整井网等措施,可提高注入水波及程度,控制含水上升速度,达到最终提高采收率的效果.

Features of the potential reservoir fractures and strategies of water-flooding development in Niujuanhu Oilfield

Xishanyao Formation of Niujuanhu Oilfield is a low-porosity,low-permeability and low-pressure reservoir,and its natural fractures are not developed.But the water-cut of a part of oil wells rises quickly and even waterflooding occurs in the initial stage of water injection.The water breakthrough features of the reservoir are analyzed according to the data of tracer monitoring,impulse well test and production performance,and it is held that the distribution of secondary fractures is wide in the studied area,the fractures are formed mainly by super-pressure water-injection and artificial fracturing,the development direction of the fractures are controlled by original maximum main stress and reservoir structure configuration.The sweeping area of injected water can be increased,the rising speed of water cut can be controlled and ultimate recovery factor can be enhanced by adopting the measures of controlling profile and plugging water,controlling water-injection pressure,injecting water to main directional water-flooded wells and adjusting well-pattern.