考虑压敏效应的变启动压力梯度试验研究  

Experimental Research on Variable Threshold Pressure Gradient Considering Pressure Sensitive Effect

作　　者：曲占庆[1] 翟恒立[1] 田相雷[2] 崔全义[3] 温庆志[1] 

机构地区：[1]中国石油大学(华东)石油工程学院,山东青岛266580 [2]中国石化胜利油田分公司现河采油厂,山东东营257000 [3]胜利油田东胜精攻石油开发集团股份有限公司,山东东营257000

出　　处：《石油钻探技术》2012年第3期78-82,共5页Petroleum Drilling Techniques

基　　金：国家自然科学基金项目"MES胶束/纳米TiO2自组装体系流变动力学研究"(编号:50904076)资助

摘　　要：低渗透变形介质油藏中流体渗流不服从达西定律,存在启动压力以及较强的压敏效应,压敏效应会对启动压力梯度产生影响。采用模拟地层水驱替存在较强压敏效应的天然岩心,测得了有效应力变化对孔隙度和渗透率的影响和单相水驱时的启动压力梯度,获得了不同有效应力作用下的孔隙度和渗透率及不同渗透率岩心所对应的启动压力梯度。采用最小二乘法对试验数据进行回归,得到了孔隙度和渗透率随有效应力变化的模型、启动压力梯度随渗透率变化的模型及考虑压敏效应的启动压力梯度数学模型,提出了变启动压力梯度的概念。研究表明,低渗透变形介质油藏的启动压力梯度随有效应力的增大而增大;在生产过程中应选择合理的生产压差和注水时机,保持合理的地层压力,防止启动压力梯度增大对产量造成影响。Due to strong threshold pressure gradient and pressure sensitive effect Darcy＇s Law cannot be used to describe fluid flow in low permeability reservoirs. To investigate the effect of effective stress on porosity and permeability as well as measuring the threshold pressure gradient in water flooding, natural cores which have strong pressure sensitivity were flooded using simulated formation water in the laboratory. Porosity and permeability under various effective stresses and threshold pressure gradient were obtained from the experiments. The mathematical model of threshold pressure gradient considering pressure sensi- tivity was established through the experimental data＇s regression by using least square method. The concept of variable threshold pressure gradient was put forward in which threshold pressure gradient will increase as effective stress increases in low permeability reservoir. So, reasonable production pressure drop and the appropriate water flooding timing should be determined so as to prevent the impact of threshold pressure gradient on production.

关 键 词：低渗透油气藏 变形介质 压敏效应 启动压力梯度 非达西流 

分 类 号：TE312[石油与天然气工程—油气田开发工程]