Quantitative Characterization Of Pore Structure And Physical Property In Shale Reservoirs

The evolution and process of pore structure and physical properties during shale reservoirs maturation are unclear.Through the research in this thesis,clarifying the evolution of pore structure and physical properties of shale with different maturities,which is of great significance for deepening the shale gas enrichment mechanism.Thus,quantitatively characterization of natural shale samples and thermal simulated shale samples are quantitatively characterized by nuclear magnetic resonance(NMR)technology;Correlation between shale TOC contents,Ro,mineral composition and physical properties and pore development are analyzed through fractal theory;Based on previous research,this paper analyzes the physical properties distribution rules and pore structure evolution rules of shale reservoirs,certain the pore control factors of shale reservoirs,establish the evolution model of pore structure of different scales in the entire hydrocarbon generation process,and deeply reveal shale reservoirs Formation mechanism of pores.The results obtained in this paper are as follows:(1)The shale pore evolution process has been restored.In addition to macropores in the thermal evolution stage,the pore volume and specific surface area of different scales have increased first in the low-maturity-mature stage and high-maturity-over-mature stage;(2)The evolution of shale physical properties is clear.The porosity in the thermal evolution stage shows an increasing-decreasing-increasing trend and reaches its peak during maturity;the permeability increases significantly during the high-maturity-over-maturity stage;(3)Reveals the controlling factors of shale pore and physical property evolution.Total organic carbon promotes the development of micropores and inhibits the development of macropores;quartz content has a negative correlation with porosity,and clay content has a positive correlation with pore volume.Porosity and permeability of both macropores and shale have a positive correlation,while micropores and porosity have a negative correlation,indicating that the development of macropores is conducive to the enhancement of pore connectivity and permeability of shale reservoirs.