Oil & Natural Gas Projects
Exploration and Production Technologies
Combined Microbial Surfactant-Polymer System for Improved Oil Mobility and
This project was selected as a Historic Black College and Universities non-competitive
Determine, through experiments and computer simulation, the best design and
evaluation of a combined microbial/surfactant-polymer system for improved oil
Prairie View A&M University
Prairie View, TX
The research conducted indicated that the improved recovery efficiency for different
nutrients appeared to be related to population numbers and not to different
recovery mechanisms. High surfactant production is the main recovery mechanism
during the NIPER 1A recovery experiments, while improved sweep efficiency is
the main recovery mechanism during the NIPER 11 experiments. These conclusions
are supported by low surface tension values during the NIPER 1A experiments
and high viscosity during the NIPER 11 experiments. It was concluded that mixed
microbial cultures hold more promise than single microbial cultures.
A microbial advanced oil recovery (AOR) technique could cost-effectively increase
oil recovery from mature domestic fields.
Many domestic oil fields are facing abandonment, although they still contain
two thirds of their original oil. A significant number of these fields can yield
additional oil using AOR techniques. Yet many independent producers do not have
the capital to implement costly advanced recovery programs. Marginal wells are
desperately in need of inexpensive AOR technologies to extend the life of oil
and gas reservoirs with unrecoverable reserves and prevent premature abandonment.
Microbial enhanced oil recovery (MEOR) technologies have become established
as cost-effective solutions for declining oil production.
Among the project highlights:
- An extensive literature review of MEOR techniques was completed in conjunction
with experimental work done in support of Task 1. An agreement was signed between
Acorn Biotechnical and Bio-Engineering International Inc (BEI) in which Acorn
received the lyophilized bacterial cultures produced by BEI and determined if
they were viable and under what conditions they could be grown. The following
cultures were shipped and were able to be revived: NIPER 1A, NIPER 6, NIPER
7, and NIPER 11A. NIPER 1A and NIPER 11 are the microorganisms most relevant
to the study.
- All of the microorganisms listed were grown under different conditions in
different media. A broth, Brewer Thyoglycolate by Difco, was selected as the
most suitable medium to grow and maintain the organisms. This broth contains
meat extract and sucrose as the principle nutrients, as well as phosphorus and
nitrogen compounds. Good growth was obtained under anaerobic or oxygen limiting
conditions. The growth under aerobic conditions was significantly less and in
some strains almost negligible. The other two nutrients used were sucrose peptone
broth and tryptic soy broth.
- NIPER 11A was observed to be limited to a salinity range of 0-4 wt % NaCl,
with an upper temperature limit of 35 C. This microbial system can tolerate
a pH range of 4.5-8.0. Other microbial strains were observed to tolerate a salinity
up to 14 wt % NaCl, when grown in tryptic soy broth, and up to 5 wt % when grown
in sucrose peptone broth. Their upper temperature limit was 45 C., with a pH
tolerance from 6.0 to 10.0. These will be useful for a wider variety of reservoir
The emphasis of this work is on the design and evaluation of a combined microbial/surfactant-polymer
system for AOR. The surfactant-polymer system will utilize bacteria that are
capable of both bio-surfactant and bipolymer production. Change in the microbial
feeding nutrients was expected to produce the change from surfactant to biopolymer
production. It was found, however, that two separate microorganisms are needed
to produce surfactant and polymer.
Laboratory experiments were done using different carbon sources in order
to determine if the microorganisms respond differently to different nutrients.
Microbial samples grown for two months were transferred to flasks with different
carbon sources. Weekly samples were withdrawn and colonies counted. Surface
tension and viscosity was measured.
Experiments in multi-layer sandpacks were performed. The different layers
were injected with one pore volume of different broths inoculated with the
appropriate microorganisms. This injection was done at a low flow rate (1
foot per day). The sandpack was closed for 6 days to allow growth and chemical
production (surfactant/polymer). After the shut-in period, the sandpack was
opened and waterflooded. The fluids were collected, and the final oil saturation
determined from mass balance.
Current Status (August 2005)
The project is in the final stages of completion.
Project Start: September 30, 2001
Project End: September 29, 2005
Anticipated DOE Contribution: $199,273
Performer Contribution: $0
NETL - Sue Mehlhoff (email@example.com or 918-699-2044 )
Prairie View - Jorge Gabitto (firstname.lastname@example.org or 936857-2427)