含水饱和度和有效应力对致密砂岩有效渗透率的影响  

INFLUENCE OF WATER SATURATION AND EFFECTIVE STRESS ON EFFECTIVE PERMEABILITY OF TIGHT SANDS

作　　者：游利军[1] 康毅力[1] 陈一健[1] 张浩[1] 尤欢增[2] 邢振辉[2] 谢婷[2] 

机构地区：[1]西南石油学院"油气藏地质及开发工程"国家重点实验室 [2]中国石化华北分公司

出　　处：《天然气工业》2004年第12期105-107,共3页Natural Gas Industry

基　　金：四川省青年科技基金项目 (编号 :0 2ZQ0 2 6 - 0 4 2 )

摘　　要：在钻井、完井和增产改造等各种作业过程中 ,近井地带由于钻井完井液的侵入 ,含水饱和度升高 ,且有效应力也发生变化 ,二者综合作用使气层有效渗透率大幅度降低。文章选取鄂尔多斯盆地上古生界典型致密砂岩样品 ,进行了恒定有效应力不同含水饱和度下气相渗透率实验、干岩样和不同含水饱和度条件下岩样应力敏感实验。实验结果表明 ,含水饱和度升高对致密砂岩气相渗透率损害严重 ;水的存在加剧了致密砂岩应力敏感程度 ,且含水饱和度越高应力敏感性越强 ;干岩样在 3MPa围压时的渗透率大约是 4 0～ 5 0MPa围压下含水饱和度为4 5 %时气相渗透率的 10～ 30 0 0倍 ,将常规测量渗透率校正为原地条件下渗透率要考虑有效应力和初始含水饱和度的影响 。During the process of drilling, completion and stimulation, the water saturation increases and the effective stress changes due to invasion of drilling and completion fluids in the zones near the borehole. Both the actions make the effective permeability of gas reservoirs decreasing greatly. With the tight sand cores from upper Paleozoic in E'erduosi Basin, the experiments of gas phase permeability are conducted with different water saturations under constant effective stress. And the experiments of stress sensitivity of the cores are also conducted with dry cores and different water saturations. The experimental results show the water saturations increasing will influence th0000000e gas phase permeability severely. The stress sensitivity of tight sands increases due to water existing. The higher the water saturations are, the stronger the stress sensitivity is. The permeability of dry cores at 3 Mpa of confining pressure is 10-3000 times larger than that of cores with 45 % water saturations at 40-50 MPa of confining pressure. The influence of the effective stress and original water saturations should be considered when the conventional measured permeability is corrected into the permeability under in-situ conditions. It is very important to prevent invasion of filtrate for protecting tight gas reservoirs.

关 键 词：含水饱和度 应力敏感 有效渗透率 致密砂岩 气层 近井地带 渗透率损害 岩样 上古生界 鄂尔多斯盆地 

分 类 号：TE373[石油与天然气工程—油气田开发工程]