Microbial Enhanced Oil Recovery (MEOR) Technology in Bokor Field, Sarawak

Abstract

Bokor field was selected as the first field in Malaysia for Microbial Enhanced Oil Recovery (MEOR) technology application which utilizes micro-organisms to facilitate, increase or extend oil production from reservoir through the production of biochemical such as biosurfactant, solvents, gases and weak acids. The field was selected due to its high viscosity crude (4 to 10 cp) and low oil specific gravity of 20° API which could resulted in low recovery factor in major reservoirs ranges from 19% to 25% of its original oil in place. This technology also seems to be attractive for the field as it was initially thought to be potential for for reducing the viscosity of the oil and thus improve oil recovery. In addition, reservoir properties for major reservoirs in Bokor field conform to the basic screening criteria of the MEOR application. This paper mainly discusses the results of the pilot project on MEOR technology application in Bokor field1. A feasibility study focusing on candidate selection and comprehensive laboratory analysis was conducted to investigate the feasibility of this technology for improving oil production/recovery. Generally, the feasibility study had indicated that there is a potential oil production improvement with no near wellbore impairment. Biodegradation study on the crude sample indicates complete removal of normal/branched alkanes and partial removal of aromatics due to in-reservoir alteration. Laboratory inoculation on the wellhead crude sample indicated that the microbes were able to slightly reduce the viscosity, break the emulsion and increase the solubility of high molecular weight component without damaging the reservoir. In order to prove the laboratory results and further assess the impact to oil production, a pilot test on three (3) selected wells were carried out. A comprehensive monitoring strategy was developed and the performances were monitored for 5 – 6 months. Over 5 months period, results from the pilot were found to be encouraging. Significant increase in oil production rate and reduction of water cut were observed demonstrating the effectiveness of MEOR application. The average oil production rate for the period increases by 270 b/d which is equivalent to 47% oil incremental. Overview of MEOR Technology Microbial Enhanced Oil Recovery (MEOR) is a technology using micro-organisms to facilitate, increase or extend oil production from reservoir. The concept is more than 40 years old, however, early proposals were poorly conceived and in most cases had no practical value. Recent studies have developed microbial biotechnology to resolve specific production problems in reservoir. MEOR processes involve the use of in-reservoir micro-organisms or specially selected natural bacteria which are capable of metabolising hydrocarbons to produce organic solvents, like alcohols and aldehydes, fatty acids surfactants and other biochemical that are known to be effective at encouraging oil mobility.

<i>Saccharomyces </i><i>cerevisiae</i> from Baker’s Yeast for Lower Oil Viscosity and Beneficial Metabolite to Improve Oil Recovery: An Overview

“…This field is the first field in Malaysia that has been selected for MEOR treatment. The low recovery factor due to low API gravity and high oil viscosity were the main reasons why this field had been chosen for MEOR treatment [17,18]. B-1, B-2 and B-3 are three from eight wells that was introduced with MEOR treatment.…”

Microbial EOR: A Quantitative Prediction of Recovery Factor

“…-viscosity reduction by gas (CO 2 , H 2 , N 2 and CH 4 ) production or degradation of long-chain saturated hydrocarbons (Maure et al 2001;Strappa et al 2004;Bao et al 2009); -improvement of rock absolute permeability by the generation of acids that dissolve rock matrix (Yakimov et al 1997); -wettability modification and reduction of oil/water interfacial tension by surfactant production and bacterial presence (Sitnikov et al 1994;Zekri et al 2003;Almehaideb et al 2004;Kowalewski et al 2006;Soudmand-Asli et al 2007; Afrapoli et al 2009); -oil viscosity reduction by biosurfactants (Maure et al 2001;Karim et al 2001;Soudmand-Asli et al 2007); -selective plugging by microorganisms and biopolymers (Yakimov et al 1997;Mezzomo et al 2000;Soudmand-Asli et al 2007); -water viscosity increase due to biopolymers (Sugai et al 1999). The main objective of this paper is the modelling of a MEOR process in which microorganisms produce biopolymers that increase water viscosity and then improve reservoir sweep efficiency.…”