Potential Fault Reactivation Analysis in Carbon Dioxide Storage

  • 廖 恒誼

Student thesis: Master's Thesis

Abstract

The purpose of this paper is to analyze pore pressure as function of time and based on critical stress fracture theory to calculate the critical pore pressure that causes faults to react We also estimated the potential of fault slips in situ The Mohr–Coulomb failure criterion and Coulomb friction criteria are used as basic theory in this study We used them in critical stress fracture theory to derive critical pore pressure equation which is expressed by minimum horizontal stress vertical stress maximum horizontal stress the coefficient of internal friction and the fault plane’s normal vector The solution was verified both in an infinite reservoir and in a no-flow boundary reservoir by comparing the results of the proposed analytical solution with the output of a standard numerical solution We used pressure change with time at specific locations wellbore locations and fault locations in the reservoir which showed that the pressure solution could be used to forecast pressure change with time at any location in the reservoir Then using the pressure solution to analyze pore pressure change with time we calculated the critical pore pressure that causes faults to slip and we estimated the potential of fault slip in an ideal model Using this ideal model we assumed the same reservoir parameters fluid parameters and stress state to investigate the effect of fault dips and the coefficient of internal friction on critical pore pressure We selected a depleted reservoir in the Tiezhanshan KCL layer as the target Using a simulator to obtain a structural model by digitizing the layer’s top structure and fault location developing a geological model by inputting geological parameters fluid parameters and stress states The numerical model was developed by using a simulator and entering well configurations and operating conditions into the geological model We studied whether carbon dioxide injection caused fault slips in faults that were originally present in the KCL layer We also output pressure change with time at the locations that based on the numerical analysis had greater possibilities for fault slips These locations included (1) the longest distance from the injector to the fault (2) the highest corner of the fault and (3) the shortest distance from the injector to the fault The critical pressure perturbation 200 years after injection at these locations was calculated and the potential of a fault slip at these locations was estimated using critical pressure perturbation
Date of Award2015 Feb 17
Original languageEnglish
SupervisorBieng-Zih Hsieh (Supervisor)

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