A multiscale hydro-geochemical-mechanical approach to analyze faulted CO₂ reservoirs

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• 作者：Ba Nghiep Nguyen ; Zhangshuan Hou ; Diana H. Bacon and Mark D. White
• 刊名：Greenhouse Gases: Science and Technology
• 出版年：2017
• 出版时间：February 2017
• 年：2017
• 卷：7
• 期：1
• 页码：106-127
• 全文大小：2462K
• ISSN：2152-3878

文摘

This paper applies a multiscale hydro-geochemical-mechanical approach to analyze faulted CO₂ reservoirs using the STOMP-CO2-R code that is coupled to the ABAQUS^® finite element package. STOMP-CO2-R models the reactive transport of CO₂ 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 CO₂ 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 CO₂ 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.