Interactions of Microbial-Enhanced Oil Recovery Processes

Abstract

Microbial-enhanced oil recovery (MEOR) has been considered as a promising technique to further increase oil recovery from petroleum reservoirs. Although the potential benefits of MEOR applications are considerable, engineering of oil recovery via the manipulation of microbial metabolism still remains an unproven concept rather than a highly desirable reality. One of the main reasons is that there are few tools appropriate to quantify the multiple metabolic and physical processes involved in the oil recovery. This study seeks to address the lack of tools by presenting a computational model for simulating coupled processes in MEOR systems with two mobile, immiscible fluids. The primary goal of MEOR is to reduce the residual oil saturation. The residual saturation changes as a function of the capillary number that defines the relative effect of viscous forces versus surface tension acting across an interface between oil and water. In all previous MEOR studies, no explicit relations between residual oil saturation and capillary number were incorporated into theoretical models although this concept is often used in commercial reservoir simulators to simulate interfacial tension (IFT) modification. In this study, a functional relation between residual oil saturation and capillary number is achieved through solution of a coupled biological (B) and hydrogeological (H) finite element model. The BH model is quite sophisticated and difficult to solve numerically, however, presentation of the model results is simple and straightforward. A robust implicit method that incorporates a number of cross couplings between the BH processes is developed to solve the BH model. The model results are presented as a simple relation between the residual oil saturation and the capillary number and are compared to data from a well-documented 123 78 J. Li et al.core-flooding experiment. The model is applied to perform parametric studies for different microbial flooding scenarios. The BH model incorporates a description of the evolution of porosity and permeability that depends on the combined effects of the interactions between the BH processes. The model is used to predict the enhancement of oil recovery in a simple homogeneous test case. The model results demonstrate that MEOR could enhance the oil recovery significantly if a larger capillary number (between 10 −5 and 10 −1 ) is achievable.

Microbial enhanced oil recovery—a modeling study of the potential of spore-forming bacteria

“…Reversible equilibrium adsorption and filtration are the two main ways for bacterial attachment. Filtration may cover both reversibly and irreversibly attached bacteria [10,20,21,35,40,51,56]. In tight rocks such as chalk bacteria may be filtered out, as described in the deep bed filtration theory, where it is generally believed that the 1/3 − 1/7 rule can be applied [52].…”

“…MEOR models have been developed with different selections of mechanisms of bacterial actions [10,14,37,40,51]. However, as mentioned earlier, the main contribution to the additional oil recovery originates from in situ surfactant production and the selective plugging effect.…”

Impact of Rock Heterogeneity on Interactions of Microbial-Enhanced Oil Recovery Processes

“…Subsequently, Nielsen et al (2010b) extended this approach to include the gravity effects, and developed a compositional streamline simulator. In our previous study (Li et al 2011), we have developed an approach to quantify the interactions of multiple contributing processes during MEOR by solving coupled flow and transport equations simultaneously. The crosscouplings are established through local rules that define the evolution of rock properties and interfacial properties such as capillary pressure and relative permeabilities.…”

“…In the present computational study, our coupled BH finite element model for MEOR (Li et al 2011) is extended to include heterogeneity of rock properties so that the resulting complex MEOR phenomena may be studied. This is achieved through the incorporation of X-ray CT image-generated rock porosity and permeability maps directly into the MEOR simulations.…”

Evaluation of a Genome-Scale In Silico Metabolic Model for Geobacter metallireducens by Using Proteomic Data from a Field Biostimulation Experiment

“…icrobial environments have been engineered for enhanced oil recovery (7,23,29,33,42) and remediation of soil and groundwater contaminated by chlorinated hydrocarbons, metals, and radionuclides (4,24,30,40,47,51,63) in the past 30 years and have recently been studied to manage carbon dioxide (46). Mathematical models of microbial processes have been used for experimental interpretation, design, and prediction in recent decades (3,10,20,22,39,48,49,53,56).…”