Fossil Fuel Bioprocessing programs
MEHR: Modeling and Monitoring
MEHR -- Microbially Enhanced Hydrocarbon Recovery -- involves a broad diversity of metabolic processes that act either individually or cooperatively to improve hydrocarbon production and energy yields, and reduce the environmental footprint. An in-depth understanding of these metabolic processes and the controlling parameters comes from focused interdisciplinary research into model organisms or communities known to perform the relevant functions.
Monitoring and Modeling: The program will ensure successful translation of laboratory-derived MEHR strategies into practice at the reservoir scale. It will do this by developing approaches to remotely monitor MEHR-induced biogeochemical transformations at the reservoir scale and developing reservoir-scale reactive transport simulators that can be used to optimize MEHR treatment design and implementation. The program will advance process understanding from pore to reservoir scales, which is critical for ensuring the successful, production-scale implementation of the MEHR treatments.
Microbial Enhanced Hydrocarbon Recovery (MEHR) strategies are being tested at the reservoir scale with mixed success, partially due to the complexity of reservoir microbial, hydrological, geochemical and geological processes that occur over a wide range of scales. The objective of this project is to develop mechanistic reactive transport modeling and advanced geophysical/isotopic approaches that can simulate and monitor the interplay of these factors, respectively. These methods help us improve our understanding of controlling MEHR processes and the design of MEHR strategies.
Characterization of field samples and laboratory experiments were performed to quantify system responses to various MEHR treatments, refine reactive transport models, and identify diagnostic geophysical or isotopic signatures of critical system transformations. For example, we investigated a microbial iron oxidation and mineral precipitation strategy designed to reduce the permeability in fast-flowing reservoir zones, thereby forcing flow through -- and sweeping oil out of -- lower permeability zones. These mineral bioclogging studies quantified the magnitude and geometry of permeability reduction due to highly localized zones of mineral precipitation. Isotopic analyses were also conducted on water and hydrocarbon samples from the Milne Point field, Alaska, providing insight into microbial and physical processes involved in both oil formation and production.
We also developed several synthetic reservoir studies during 2012. These studies were based on our previous column experiments that stimulated the bacterium Leuconostoc mesenteroides to produce pore clogging dextran and monitored the associated complex resistivity and seismic signatures of such clogging. Simulation results indicated that the effectiveness of plugging was largely controlled by sucrose and bacteria injection rates and the chemistry of the injection and formation waters. This was the first work that examined the controlling parameters that affect selective plugging at the field scale within the context of MEHR. The study also documented the expected seismic and electrical detectability and resolvability of the MEHR treatment at the field scale.
Published in 2012
Reactive Transport Modeling of Induced Selective Plugging by L. Mesenteroides in Carbonate Formations, Javier Vilcáez, Li. Li, Susan S. Hubbard, Geomicrobiology Journal (In Press).
High-Frequency Seismic Response During Permeability Reduction due to Biopolymer Clogging in Unconsolidated Porous Media, Tae-Hyuk Kwon and Jonathan B. Ajo-Franklin, Geophysics (In Press)