HR: 17:00h
AN: H44D-05 [Abstracts]
TI: Physical Constraints on Microbially Enhanced Oil Recovery
AU: * Marshall, S L
EM: Simon.Marshall@csiro.au
AF: CSIRO Land and Water, Underwood Avenue, Floreat Park, Perth, WA 6014, Australia
AB:
Secondary and tertiary oil recovery from mature or depleted
reservoirs usually involves modification of fluid properties (especially
the oil-water interfacial tension), or increasing the efficiency of
water flooding by selective permeability reduction. The use of microbes
for both of these strategies - through production of biosurfactants
and extracellular polymeric material, respectively - is the subject of
considerable current interest, but as pointed out by Bryant and Lockhart
[SPE paper 79719, 2002] is constrained by chemical reaction kinetics.
Continuing in the spirit of the engineering analysis
presented by these authors, the purpose of this paper is to consider,
on the basis of simplified physical models, the constraints
that apply to the injection of microbes as a concentrated slurry and
their subsequent dispersion through the pores of the formation. This involves
solution of the advection-dispersion equation in conjunction with the
Newtonian flow distribution between an injection well and a
production well, and a more general flow distribution based on a
non-Newtonian (power-law) constitutive equation used to describe the
rheological properties of concentrated suspensions. By analogy with the
better-known example of blood flow through capillaries, such deviations
from Newtonian flow behavior are expected to become more significant in
flow through media of low permeabilities, where the diameters of the
suspended particles are non-negligible in relation to the mean diameters
of the flow channels. The nature and extent of these deviations
from Newtonian behavior are examined by calculating the pressure drops
corresponding to a given flow rate in one dimension at different suspension
concentrations, and the nonlinearities resulting from retention or
`filtration' of bacteria by the porous medium are investigated by performing a
population-balance analysis to determine the evolving profiles of
retained bacteria as a function of distance and time. These calculations
are intended to provide a `baseline' for interpreting the results produced
by simulation software, in which the additional complexities associated
with multiphase flow and interactions between introduced and indigenous
microbial populations are included.
DE: 0418 Bioremediation
DE: 1805 Computational hydrology
SC: Hydrology [H]
MN: 2007 Fall Meeting