Evolution of Pore Connectivity in the Fushun Oil Shale by Low-Field Nuclear Magnetic Resonance Spectroscopy

doi:10.11938/cjmr20182687

Abstract

Abstract: During in-situ exploitation of the oil shale, the connectivity of the pore structure of the reservoir directly affects not only the flow behavior and heat transfer efficiency of the heat-carrying medium, but also the diffusion and flow behaviors of the oil and gas. In this study, the T₂ spectra of saturated water and bound water in samples from the Fushun oil shale were measured with low-field nuclear magnetic resonance at different final pyrolysis temperatures (23~650℃). NMR pore parameters, including T₂ cutoff value of movable fluid, bound fluid porosity, saturated fluid porosity and permeability, were analyzed. The evolution of pore connectivity of the oil shale with final pyrolysis temperature was studied quantitatively. The results demonstrated that final pyrolysis temperature affected the variations of pore connectivity and the permeability of oil shale. The increase of total porosity could be attributed mainly to the increments of movable fluid. These results indicated that increases in final pyrolysis temperature enhanced the permeability and transport of oil and gas, providing a basis for further understanding of the evolution of pore structure in oil shale in-situ pyrolysis.

Key words: oil shale, in-situ pyrolysis, low-field nuclear magnetic resonance, porosity, connectivity

CLC Number:

O482.53
TD84

LIU Zhi-jun, YANG Dong, SHAO Ji-xi, HU Yao-qing. Evolution of Pore Connectivity in the Fushun Oil Shale by Low-Field Nuclear Magnetic Resonance Spectroscopy[J]. Chinese Journal of Magnetic Resonance, 2019, 36(3): 309-318.

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