The Influence Of Confining Pressure On The Resistivity Of Low-Permeability Rocks

The evaluationof thecomplex low porosity and permeability reservoirs has been an important part of research and exploration for petroleum geologists at home and abroad.Rocks are usually in the low confining pressure condition,the changes of rock resistivity is directly related tothe changes of rock porosity,and rock resistivity is mainly caused by the change of the conductive water network paths,which is caused by the change of pores,pore throat,bores.The paper will analyze and evaluate the existing relational mode about how confining pressureaffects rock resistivity,according to the characteristics of the target reservoir rock,and then the paper will establish theoretically the experimental model about confining pressure and sandstone resistivitybased on literature research,and then we will carry out petrophysical and joint measurement experiments in order to study the influence of the above relationship.Finally,we will determine the relationship between confining pressure and rock resistivity form twoaspect with the theoretical analysis and experimental verification,the achievements at present are as follows:Experimental device was designed and improved,we used conventional method of measuring capillary pressure and took advantage of the displacement process,the rock resistivity was tested preciselyby changing overlying confining pressure to record rock resistivity;The influence of confining pressure on the resistivity of low-permeability rocks show that: the rock poresandrock throats are caused by the change of confining pressure,so that the influence of confining pressure on the resistivity of low-permeability rock is big;The capillary of rock samples are different,which reflects the rock samples sorted and irreducible water saturation areboth different;Thejoint experiment of confining pressure on the resistivity of low-permeability rocks show that: measuring the different experimental rock porosity,different voltages,frequencies and saturated brine will have an impact on rock resistivity,and thus the influence of confining pressure on therock resistivity is affected.