Stress Sensitivity of Low-permeability Sandstone Reservoir

In the time of low-permeability sandstone reservoir explored,effective stress rise gradually,stress sensitivity has happened,which cause permeability decline. Allowing to initial geostress,the study on Jilin oil field xin326 oil layer and made the rock core experiment are presented. The experimental results show that the stress sensitivity of this oil layer is small;the regularity of permeability changes is in accordance with exponential function .The stress sensitivity of high permeability core is larger than low permeability. Moreover,experiments and theoretical analysis shows that low permeability core has a smaller permeability loss than high permeability core in load and unload process. Load and unload process leads to elastic plastic deformation of rock,this is the major reason which permeability can not return completely.