A Study On The Characteristics Of Shale Pore Structure In Yu106 And Its Influence On Gas Production

Shale gas reservoir has strong physical properties,heterogeneity and sensitivity,so has certain influence on gas well productivity and ultimately is decided by its complex micro pore structure.The research on microscopic pore structure of shale reservoir can help understand the effect of microscopic pore structure on gas production.To analyze the reservoir characteristics and microscopic pore structure,a series of experiments have been conducted.Theses experiments include core observation,casting thin sections identification,electron scan microscope(ESM),nitrogen stripping-absorption,mercury injection,nuclear magnetic resonance(NMR),and sensitivity evaluation.In the end,the effect of reservoir characteristics on the capacity of the studied areas and the effect of micro pore texture on reservoir damage sensitivity have been analyzed.Based on the above analysis,the following results can be obtained: the clay contents in Shanxi formation is higher than brittleness content.The pore types of the studied areas are mainly intergranular pore,intragranular pore,and many micro cracks.The threshold pressure of Shanxi formation is higher,its separation is not good,but with fine flexure,fine throat and no mercury into the platform.The porosity of the reservoir rock of Shanxi formation is given priority to micro pores,pore throat combination relationship is the micro pore and micro throat.Organic carbon(TOC),clay types,kerogen and thermal evolution degree are in control with shale microscopic pore growth.But organic pore types,clay mineral types and the development of clay mineral micro porous are also controlled by the thermal evolution degree.The research of this thesis suggests: the effect of thermal evolution degree is very important in the process of microscopic pore development.The reservoir contain some acidity minerals,such as chlorite,debris,feldspar,carbonate and so on,which would react with some acidity minerals producing potential acid damage.The montmorillonite,illite,and kaolinite will swell and fall off if they are in contact with water,which result in potential velocity sensitivity.The similar damage like alkali sensitivity and salinity sensitivity can also occur.