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A multiscale hydro‐geochemical‐mechanical approach to analyze faulted CO 2 reservoirs
Author(s) -
Nguyen Ba Nghiep,
Hou Zhangshuan,
Bacon Diana H.,
White Mark D.
Publication year - 2017
Publication title -
greenhouse gases: science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.45
H-Index - 32
ISSN - 2152-3878
DOI - 10.1002/ghg.1616
Subject(s) - geology , caprock , slip (aerodynamics) , hydraulic fracturing , geomechanics , fault (geology) , permeability (electromagnetism) , albite , stress (linguistics) , petrology , geotechnical engineering , quartz , seismology , physics , genetics , membrane , biology , thermodynamics , paleontology , linguistics , philosophy
This paper applies a multiscale hydro‐geochemical‐mechanical approach to analyze faulted CO 2 reservoirs using the STOMP‐CO2‐R code that is coupled to the ABAQUS ® finite element package. STOMP‐CO2‐R models the reactive transport of CO 2 causing mineral composition changes that are captured by an Eshelby‐Mori‐Tanka model implemented in ABAQUS ® . A three‐dimensional (3D) STOMP‐CO2‐R model for a reservoir containing an inclined fault was built to analyze a formation containing a reaction network with five minerals: albite, anorthite, calcite, kaolinite, and quartz. A 3D finite element mesh that exactly maps the STOMP‐CO2‐R grid was developed for coupled analyses. The model contains alternating sandstone and shale layers. The impact of reactive transport of CO 2 on the geomechanical properties of reservoir rocks are studied in terms of mineral composition changes that affect their geomechanical responses. Simulations assuming extensional and compressional stress regimes with and without coupled geochemistry are performed to study the stress regime effect on the risk of hydraulic fracture. The fault slip is examined as functions of stress regime, geomechanical, geochemical‐mechanical effects, fault inclination, and position. The results show that mineralogical changes due to CO 2 injection reduce the permeability and elastic modulus of the reservoir, leading to increased fluid pressure and risk of fracture in the injection location and the caprock seal. Shear failure in the fault leading to fault reactivation was not predicted to occur. However, stress regime, fault inclination, and fault position in light of the coupled hydro‐geochemical‐mechanical analysis have an important impact on the slip tendency factor and elastic fault slip. © 2016 Society of Chemical Industry and John Wiley & Sons, Ltd.