Abstract:

Three types of pore-structure study methods including scanning electron microscope(SEM), nuclear magnetic resonance(NMR) and computer tomography(CT) scanning were used to analyze the shale. The research results show the following aspects: (1)SEM has a good ability of observation for the partial of shale and can directly reflect the information such as types, shapes of micro pores of shales; after argon-ion milling, nano-size pores are able to be observed; combined with ImageJ, the plane porosity can be obtained. But SEM cannot reflect the overall characteristics of samples very well. (2)The rock matrix makes little influence on NRM, so NMR can determine porosity and more accurately analyze the pore size distribution, pore connectivity and movable fluid saturation of shale. Through NMR, the overall characteristics of the samples can be gotten, but the details are not involved. (3)CT scanning is capable to do quantitative analysis for the shale component and to build a 3D model which shows the distribution of pores and high density matters in the shale by the 3D reconstruction technique, so macroscopic observation for the shape and spatial allocation of pores is available. One disadvantage of CT scanning is that the threshold choice has an influence on results of 3D reconstruction. Only with the comprehensive use of these three methods, can a more accurate analysis on the pore structure of shale reservoirs be done, as a result, a more perfect data of pore structures can be gotten.

Key words: shale, reservoir, pore structure, scanning electron microscope, nuclear magnetic resonance, computer tomography scanning