Title

Evolution of Shale Microstructure under Microwave Irradiation Stimulation

Abstract

As the low permeability of shale gas reservoirs limit its large-scale commercial development, the microwave irradiation stimulation is proposed as a new approach to increase the shale gas reservoir's production. In this study, in order to investigate the microwave's effect on shale pore structure, experiments were performed using nuclear magnetic resonance to compare the pore size distribution of shale samples before and after microwave treatment. The results showed that the numbers as well as sizes of mesopores and macropores in shale samples increased, while the number of micropores decreased after the microwave irradiation. This is benefit to enhance shale gas flow in reservoirs. In addition, the moisture within the shale samples increased its ability to absorb microwave energy, leading to a positive effect on the increase of breathable pores and microfractures. When the accompanying thermal stress and vapor pressure generated inside the shale is larger than the cementation strength between the shale mineral particles, the shale cracks and forms microcracks until it is destroyed. The experimental results demonstrated that the microwave stimulation is effective in expanding breathable pores and inducing fissures in shale samples; it may therefore have applications in enhancing shale gas reservoirs.

Department(s)

Mining and Nuclear Engineering

Comments

This work was supported by the Petrochemical Joint Funds of the National Natural Science Foundation of China and the China National Petroleum Corporation (grant number U1762105). the National Natural Science Foundation of China (grant number 51774279); and the Fundamental Research Funds for the Central Universities (grant number 2015XKZD04).

Keywords and Phrases

Cements; Flow of gases; Gas permeability; Information dissemination; Irradiation; Low permeability reservoirs; Magnetic after effect; Microcracks; Petroleum reservoir engineering; Pore size; Shale gas; Commercial development; Low permeability; Microfractures; Microwave energies; Microwave treatment; Mineral particles; New approaches; Shale gas reservoirs; Microwave irradiation

International Standard Serial Number (ISSN)

0887-0624; 1520-5029

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2018 American Chemical Society (ACS), All rights reserved.

Publication Date

01 Nov 2018

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