Experimental comparison study of stress sensitivity at different levels of permeability core

Whether the stress sensitivity in the mid-high permeability is stronger than that in the low permeability reservoir is current hot debate, aimed at this question. 14 samples are selected to calculate the permeability loss rate separately in the laboratory simulation experiment, the results show that the absolute value of loss rate of the mid-high permeability core is higher than that of low permeability core, but the relative permeability loss rate is lower than that of low permeability core, which, namely, means the low-permeability reservoir has stronger stress sensitivity. The stress sensitivity curve in the high permeability reservoirs could be classified into the type model of "gentle", while the stress sensitivity curve in the low permeability reservoir could be concluded as the "first steep then slow" mode. Hence the bottom-hole flowing pressure must be controlled reasonably in order to keep the productivity well.