摘要
目前新探明的油藏近30.9%的储量都是低渗透油藏,由于低渗透裂缝性油藏基质渗透率低、裂缝分布复杂,常常会出现油井过早水淹导致开发效果差。而裂缝性油藏渗吸过程中受裂缝发育程度、毛管力大小、润湿性、初始含水饱和度、基质与裂缝渗透率之比等10多种因素影响。现在大多数研究都是基于物模方法,数模研究相对较少,现通过建立了典型的渗吸数值模型(岩心规模和近井规模)对多种因素进行了规律研究,为有效利用基质与裂缝渗吸作用对开发效果进行改善提供指导。通过研究完善,加深了对各影响因素的影响程度的认识,其中毛管力对渗吸至关重要,油水粘度比、基质与裂缝渗透率之比、注入速度、初始含水饱和度、温度是渗吸的敏感因素,其余因素影响不明显。
At present, almost 30.9% of proven petroleum reserves belong to low–permeability reservoirs. Due to the low matrix permeability and complex fracture distribution of low-permeability fractured reservoirs, premature oil well flooding usually occurs and leads to poor oil recovery. Moreover, the imbibition process in fractured reservoirs is affected by more than 10 factors including the fractures, capillary force, wettability, initial water saturation, matrix to fracture permeability ratio. Currently, most studies were based on physical model tests, rather than numerical simulation. A typical numerical model （core scale and near wellbore region scale） was built and parametric studies were carried out on nine factors influencing the imbibition process. The results provide some guidance for improving the oil recovery by making use of imbibition between matrix and fractures. It was found that the capillary force is a very important factor. Wettability, initial water saturation, matrix to fracture permeability ratio are also sensitive factors, and the effects of other factors are not evident.
基金
国家自然科学基金(40974055)
中国石油科技创新基金研究项目(2009D-5006-02-01)
关键词
低渗透
渗吸过程
典型数值模型
影响因素
对比分析
low permeability
imbibition process
typical numerical model
influencing factor
comparative analysis
