Earth Sciences Division Berkeley Lab
Hydrogeology and Reservoir Dynamics Department
developed at LBNL some years ago. The latter includes the so-called systematic testing, which is a repeated set of experiments at regularly space distances along an underground tunnel to provide unbiased data for stochastic modeling.
Annual Report 1999 - 2000
the hydrofracturing process, using injection wells. Advanced and unconventional well-test methods to determine and characterize production zones have been developed. Pore network models are being developed to understand drainage and imbibition processes in reservoir rocks during flooding operations. An interesting application being studied is the diatomic fields, which represent potentially billions of barrels of high-quality oil. However, production from the diatomites requires a secondary recovery process because of their low permeability, even though they have high porosity. Research into hydrofracturing with flooding is being conducted to explore optimal production strategies.
FLOW AND TRANSPORT MODELING
HRD has a long history in numerical modeling of flow and transport in geologic media. A suite of numerical models using finite-difference, finite-element and integrated finite-difference methods has been developed. The most well-tested and applied computer code is the TOUGH family of simulators, which calculates flow and transport of multi-phase multi-component fluids in complex fracture-porous media. Anumber of equation-of-state packages have been developed for different fluids appropriate for environmental, nuclear waste disposal, oil and gas and geothermal reservoir applications. Associated with these codes are the iTOUGH codes, which perform the inverse calculations of parameter estimation for such complex systems. Current development involves implementation of reactive chemistry into the TOUGH codes. This includes both homogeneous reactions, such as aqueous complexation and redox reactions, and heterogeneous reactions such as ion exchange, adsorption, mineral dissolution and precipitation, and gas dissolution and exsolution. The new code is called TOUGHREACT, which has already been applied to analyzing several sets of real field data with success. The coupling of mechanical stress and temperature effects of permeability of fractured rocks is important in injection testing, stimulation of oil and gas reservoirs and nuclear waste repository performance. HRD’s work involves the development of a coupled thermo-hydro-mechanical (THM) simulator for modeling of fully coupled HM processes in saturated and unsaturated media. Asecond effort has been the coupling of two powerful existing codes, TOUGH2 and the industry-standard code FLAC3D. The latter calculates mechanical and thermal-hydro-mechanical processes in soil and rock mechanics. The joining of these two codes gives us a new capability to address these coupled THM problems.
FUNDING
Funding for the Hydrogeology and Reservoir Dynamics Department comes primarily from the U.S. Department of Energy, including: Office of Science, Office of Basic Energy Science, Geosciences Research Program; Offices of Biological and Environmental Research; Assistant Secretary for Energy Efficiency and Renewable Energy, Office of Geothermal Technologies; Office of Civilian Waste Management; and Assistant Secretary for Environmental Management. The department receives funding support also from the U.S. Environmental Protection Agency. Other funding is provided through the Laboratory Directed Research and Development program at LBNL.
RESERVOIR ENGINEERING
HRD is also very active in the study of oil and gas reservoirs. This includes optimization and control theory to maximize oil production with
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