孔隙型与裂缝—孔隙型碳酸盐岩储层应力敏感研究

THE STRESS SENSITIVITY RESEARCH ON POROUS AND FRACTURED POROUS CARBONATE RESERVOIRS

与砂岩储层应力敏感性研究深入程度相比,碳酸盐岩储层应力敏感性研究只是最近几年来才引起重视。以川东北三叠系飞仙关组典型孔隙型及裂缝—孔隙型碳酸盐岩储层为对象,通过实验对比研究了两类储层的应力敏感特性,采用应力敏感系数评价应力敏感程度,从孔隙结构和裂缝特征阐述了二者应力敏感行为的差异。研究表明,裂缝—孔隙型储层岩样应力敏感系数比孔隙型的大。前者应力敏感程度为中等偏强,后者应力敏感程度为弱。孔隙型岩样的形变基本上属于弹性形变。裂缝—孔隙型岩样的形变属于塑性形变的范畴。有效应力增加时,裂缝首先被压缩闭合。

Comparing with extensive researches on stress sensitivity of sandstone reservoirs, carbonate reservoirs is paid more and more attention in recent years. The samples are collected from carbonate gas reservoirs of Feixianguan formation of Triassic in Northeast Sichuan Basin. The stress sensitivity experiments are conducted with porous and fractured porous carbonate cores .The stress sensitive coefficient is applied in ensitive coefficient of fractured porous cores is bigger than that of porous cores. The stress stress sensitivity evaluation. Finally the different behavior of stress sensitivity is explained by pore structure and fracture character. The experiment results show that the stress s sensitivity of the former is weak, whereas the latter's is middle-strong. The deformation of porous medium belongs mainly to elastic, whereas fractured porous' belongs to plastic. With the effective stress increasing, fracture is firstly compressed to close, and is followed by deformation of porous.