Pore structure characterization and fractal study of low-resistivity shales in Changning area
For the study of pore development characteristics of low-resistivity shales in Changing area,Sichuan Basin,a series of experiments,such as organic carbon analysis,nitrogen adsorption,XRD mineral composition analysis,and scanning electron microscopy were carried out,and differences between low-resistivity shale and conventional shale in Changning area were studied through comparative method.The pore structures and fractal characteristics of the low-resistivity shale reservoirs were Clarified,and their controlling factors were revealed.The results show that the pore development degree of most low-resistivity shales in Changning area is significantly worse than that of con-ventional shales.Among them,the difference in pore volume is mainly reflected in the pore size range of 2～20 nm,and the difference in specific surface area is primarily concentrated in the segments less than 1.5 nm and more than 1.8 nm.The pore structure of the shale reservoirs tends to worsen with the decrease in resistivity.The organic matter content and maturity have a more obvious influence on the reservoir capacity of low-resistance shales.Compared with conventional resistance shales,small pores of low-resistance shales develop more complex pore sizes and pore walls.The effects of clay minerals and pyrite on the fractal dimension of shales with different resistivity are consistent.In contrast,the effect of organic matter on the fractal dimension of shales with different resistivity are opposite.The effect of organic matter on fractal dimension is closely related to the change of organic pores of over-evolutional shales after graphitization.
NETL
NSTL
万方数据
维普
