首页|A method for monitoring acoustic emissions in geological media under coupled 3-D stress and fluid flow

A method for monitoring acoustic emissions in geological media under coupled 3-D stress and fluid flow

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  • NSTL
  • Elsevier
Fracturing is a critical process affecting rock deformation and geofluid flow in underground engineering. However, previous studies coupled 3-D geomechanics and geofluids rarely considered the process of rock frac-ture in real time due to the lack of experimental apparatus. In this work, we present an auxiliary device for an existing true triaxial geological apparatus, with which we implanted AE modules into loading platens with grooved fluid channels, to better collect fracture-related acoustic emission signals and their locations. We minimize the end-friction effect in terms of the performance of the auxiliary device, loading method, and pro-gram of experiments. Our case study used a cubic sandstone specimen to investigate stress-strain behaviors, the evolution of intrinsic permeability, and the spatiotemporal characteristics of acoustic emissions (AE) under true triaxial stress coupled with CO2 gas flow (1 MPa at the inlet and atmosphere at the outlet). We found an obvious correlation between AE characteristics and the evolution of permeability. The AE signals could be applied to identify the fracture mode that triggered the essential change in rock permeability from a decrease to an increase. Furthermore, the AE source locations suggest the polymodal faulting mode of specimen failure, which is consistent with previous studies and our computed tomography (CT) scanning images. The case study also demonstrated the effectiveness and reliability of the device developed, which can play an important role in studies of oil and gas exploration and geological sequestration of CO2.

Acoustic emissionTrue triaxial stressFluid-solid couplingFracture evolutionAE source LocalizationSandstoneINTERMEDIATE PRINCIPAL STRESSTRUE TRIAXIAL APPARATUSFAILURE CHARACTERISTICSPERMEABILITY EVOLUTIONPOROUS SANDSTONESROCKSCOALDAMAGEDEFORMATIONCOMPACTION

Huang, Jie、Qin, Chao-Zhong、Niu, Yong、Li, Rui、Song, Zhenlong、Wang, Xiaodong

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Chongqing Univ

Shaoxing Univ

Southern Univ Sci & Technol

2022

10.1016/j.petrol.2022.110227

Journal of Petroleum Science & Engineering

Journal of Petroleum Science & Engineering

ISSN：0920-4105
年,卷(期)：2022.211
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