Geomechanical Simulations of Caprock Integrity Using the Livermore Distinict Element Method
Large-scale carbon capture and sequestration (CCS) projects involving annual injections of millions of tons of CO2 are a key infrastructural element needed to substantially reduce greenhouse gas emissions. The large rate and volume of injection will induce pressure and stress gradients within the formation that could activate existing fractures and faults, or drive new fractures through the caprock. We will present results of an ongoing investigation to identify conditions that will activate existing fractures/faults or make new fractures within the caprock using the Livermore Distinct Element Code (LDEC). LDEC is a multiphysics code, developed at LLNL, capable of simulating dynamic fracture of rock masses under a range of conditions. As part of a recent project, LDEC has been extended to consider fault activation and dynamic fracture of rock masses due to pressurization of the pore-space. We will present several demonstrations of LDEC functionality and an application of LDEC to a CO2 injection scenario. We present results from our investigations of Teapot Dome using LDEC to study the potential for fault activation during injection. Using this approach, we built finite element models of the rock masses surrounding bounding faults and explicitly simulated the compression and shear on the fault interface. A CO2 injection source was introduced and the area of fault activation was predicted as a function of injection rate. This work presents an approach where the interactions of all locations on the fault are considered in response to specific injection scenarios. For example, with LDEC, as regions of the fault fail, the shear load is taken up elsewhere on the fault. The results of this study are consistent with previous studies of Teapot Dome and indicate significantly elevated pore pressures are required to activate the bounding faults, given the assumed in situ stress state on the faults.
- Research Organization:
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 936977
- Report Number(s):
- LLNL-PROC-403056; TRN: US200821%%177
- Resource Relation:
- Conference: Presented at: Seventh Annual Conference on Carbon Capture and Sequestration, Pittsburgh, PA, United States, May 05 - May 08, 2008
- Country of Publication:
- United States
- Language:
- English
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