单井注水替油过程中缝洞单元内的油水关系

Relationship between oil and water in fracture-cave unit during the course of
single-well flooding drive

钟伟 陆正元

成都理工大学油气藏地质及开发工程国家重点实验室，四川 成都 610059

State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Chengdu University of Technology, Chengdu 610059, China

在单井控制的局限封闭储层中，单井注水替油是一种提高采收率的好方法。塔河油田奥陶系碳酸盐岩缝洞高度发育,并以多缝洞系统的形式彼此孤立存在，这种特殊的地质特征为单井注水替油创造了有利条件。通过对典型单井控制的T751井缝洞单元注水替油过程中油水关系变化的分析认为：有限范围内缝洞单元产油的主要能量来自地层剩余油体膨胀，注水主要是增加油体能量。单井注水替油可以开发井孔储层下方的油体，油井持续高产水后，需通过注气或侧钻结合注水等措施开采井孔上部储层中的剩余油。

In local composite bounded reservoir controlled by single well, single-well flooding drive is a good way to enhance oil recovery. The Ordovician carbonate of Tahe Oilfield has developed a great deal of fractures and caves and exists isolatedly with each other as fracture-cave system. This special geologic characteristic provides a beneficial condition for extracting oil by water injection in single well. According to the analysis to water-oil relationship in the course of water injection to fracture-cave unit controlled by Well T751,we have get the following conclusion: the main driving energy in local composite bounded reservoir comes from the
expansion of remaining oil, the injection is mainly increasing the energy of oil volume, the oil volume in layers lower than that penetrated can be recovered by single-well flooding, and the residual oil in the upper reservoirs should be recovered by gas injection or sidetrack drilling when the well has an extended high water rate.