Experimental comparison study on stress sensitivity of different permeability cores

The phenomenon of stress sensitivity happens inevitably in the process of recovery in most reservoirs. Whether the stress sensitivity in the mid-high permeability reservoir is stronger than that in the low permeability reservoir is a hot topic currently Aiming at this question, laboratory simulation is conducted. 14 samples are selected to test the permeability reduction ratio separately on the indoors simulation experiment, showing that the absolute value of reduction ratio of the mid-high permeability core is higher than that of low permeability core, but the relative permeability reduction ratio is lower than that of low permeability core, which, namely, means the low-permeability reservoir has stronger stress sensitivity. The stress sensitivity curve in high permeability reservoirs could be classified into the type mode of "gentle", while the stress sensitivity curve in the low permeability reservoir could be the type mode of " slow after steep". Hence the bottom-hole flowing pressure must be controlled properly in order to keep the productivity of the well.