吉林油田火山岩特低渗气藏应力敏感性及成因研究

以吉林油田长岭火山岩气藏基质岩心、裂缝充填岩心、裂缝-基质岩心为研究对象,进行了油藏条件下的应力敏感实验,以储层原始有效覆压下的渗透率为基准渗透率评价了该火山岩气藏的应力敏感程度,并与传统评价方法进行了对比.研究结果表明:火山岩裂缝-基质岩心具有中等偏强的应力敏感性,基质岩心和裂缝充填岩心应力敏感程度较弱.这与用传统方法评价的3类岩心均具有极强应力敏感性的结果偏差较大,火山岩中天然缝和人工缝的闭合是造成应力敏感性的主导因素.由于有效覆压变化引起的渗透率损失主要在低有效覆压范围内(<20 MPa),而这种情况在整个油气藏开发期内可能并不会存在,因此认为新评价方法更加具有应用价值.

Stress sensitivity of extra-low permeability volcanic gas reservoir Jilin Oilfield and its origin

Volcanic gas reservoir becomes an important domain of natural-gas exploration and development for petroleum resources in China,however the sensitivity of volcanic gas reservoir and its origin remains unknown.According to the classification of matrix cores,fracture filling cores and fracture-matrix cores,the permeability stress sensitivity of Changling volcanic gas reservoir natural cores were measured through laboratory experiments.With the permeability under initial effective overburden pressure as intrinsic permeability,the stress sensitivities of three type of cores were measured compared with traditional methods.The results indicated volcanic rock fracture-matrix cores stress sensitivity are medium-to-strong while the fracture filling cores and fracture-matrix cores are weak,artificial fracture and natural fracture are the main causes of core permeability stress sensitivity.As the loss of permeability mainly at the low effective overburden pressure(<20 MPa),that is seldom happens at the development of the gas or oil field,thus the new evaluation method is more valuable.