SPE DL: Chemical EOR - The Past; Does It Have A Future?

Wednesday, 19 April 2006 Read 5442 times
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Chemical EOR methods indeed have a future, a very bright one too.  Consider, nearly two trillion barrels of conventional oil worldwide that will be left unrecovered when primary and secondary recoveries have been exhausted.  The greater portion of this oil will have to be recovered by clever chemical EOR methods, because other methods are frequently inapplicable, due to unavailability of suitable fluids, among other reasons. 

Chemical EOR methods include utilization of polymers, surfactants, alkaline chemicals and their combinations, as in ASP (Alkaline-Surfactant-Polymer), or use of microemulsions as in micellar flooding.  Hundreds of field tests have been carried out, with little “technical success”, (viz. production of incremental oil), let alone commercial success.  Micellar flooding has been more successful in this regard, at least as far as recovery of tertiary oil is concerned.  ASP has been reported to be successful in a few field tests.  The economics of both processes were unfavourable until recently, but need to be reevaluated under the current oil prices.

The reasons for the lack of success include inadequate understanding of the process itself, unscaled laboratory experiments, and low oil prices, exacerbated by less than adequate definition of reservoir geology.   Much can be learned from past failures: first about the limitations of a given process, and second, about how a process can be modified for a given reservoir – if at all it is feasible.  The looming energy crisis necessitates the application of suitable chemical EOR methods for additional oil recovery.  Coupled with today’s trend in oil prices, chemical methods stand to hold a bright future sooner than later.

We need to develop reservoir specific EOR technologies, with focus on commercial viability.  Examples are offered for selected reservoir conditions.  As the oil price increases, so does the cost of chemicals, but in a different proportion.  Other important aspects of chemical EOR, viz. types of research and pilot testing needed, development of new methods and scaling criteria for reliable laboratory experiments are also discussed.


Sara Thomas manages research for PERL Canada, Ltd.  She holds B.Sc. and B.Ed. degrees from the University of Kerala, India and a Ph.D. in Chemical Engineering from the University of Birmingham, U.K. She worked as a research associate and conducted research on Chemical EOR methods for 25 years. She has taught courses in petroleum engineering at the university of Alberta for 5 years.  She has authored and co-authored 43 papers and 12 research reports on various EOR processes.  Currently, she offers courses on EOR methods, miscible and immiscible flooding, gas injection and scale up methods for EOR processes.

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