IPA14-SE-119 PROCEEDINGS, INDONESIAN PETROLEUM ASSOCIATION Thirty-Eighth Annual Convention & Exhibition, May 2014 A CRITICAL REVIEW OF MICROBIAL ENHANCED OIL RECOVERY USING ARTIFICIAL SANDSTONE CORE: A MATHEMATICAL MODEL Farizal Hakiki* ABSTRACT Enhancing the amount of oil recovered from a mature field has become the standard procedure of the life cycle of an oil well. The need for a green application leads Microbial Enhanced Oil Recovery as an empowered technology that supports environmental tranquility. The present paper exposes the mathematical model of previous experiment results of applying indigenous bacteria Bacillus sp. and Bacillus polymyxa on oil samples from Handil Field in Indonesia. The experiment performed by Bitticaca (2009) was a cultivation of those bacteria adapted on SMSS with 0.01% (m/v) NPK + 20% (v/v) oil sample. The growth of bacteria was recorded every 24 hours for 7 days. The optimization of the inoculum ratio was then made by looking at the ability to alter the physical characteristics, such as the viscosity and interfacial tension, of crude oil. The characteristics alteration is caused by biosurfactant production; hence, the growth data of bacteria and biosurfactant production are modeled in mathematical equations and approached by coupling logistics-growth and a modified predator-prey model. The equations are then solved using analytical and finite difference methods. Since every bacterium has its own special growth rate, carrying capacity and toxicity constant, these equations are beneficial for the optimization of inoculum of Bacillus sp. and Bacillus polymyxa. The experiment reveals that the mixed culture of bacteria (1:1) is better compared with the synthetic surfactant. A simple equation was numerically developed to predict the recovery factor due to MEOR and validated with Priharto’s laboratory data (2009) of bacterial coreflooding using an artificial sandstone core within 7 days incubation (shut-in period), 0.88 cc/minute injection, overburden pressure 100 psi and 55 C temperature. Thus, this investigation on developing related mathematical model would contribute to a further study of conducting an eco-friendly Enhanced Oil Recovery via MEOR to a mature sandstone- dominated reservoir. * Institute of Technology Bandung Keywords: Microbial Enhanced Oil Recovery (MEOR), Biosurfactant, Sandstone Core, Mathematical Model INTRODUCTION EOR is aimed at reducing the remaining oil saturation, reducing the water cut, increasing the sweep efficiency at the waterfront and ensuring more oil is ‘pushed’ to the production well. One tertiary oil recovery method that has potential to be eco-friendly to improve oil production is Microbial Enhanced Oil Recovery (MEOR). MEOR employ microorganisms whether in whole cell or their bioproducts to increase oil production by altering the oil and reservoir characteristics. Numerous studies have been carried out to investigate the mechanisms and feasibility of MEOR technology worldwide. In Indonesia, MEOR field trials was conducted at Ledok Field, Central Java in 1999 by PERTAMINA. The purpose of this paper is developing and validating mathematical predictive model of (a) Bacteria-Bio-surfactant Growth, (b) IFT Model, (c) Viscosity Model, (d) CMC Model and (e) Recovery Factor Model that could be beneficial in advanced MEOR simulation. EXPERIMENTAL WORK REVIEW The experiment data were abstracted from literature provided by Bitticaca (2009) and Priharto (2009). Bittacaca’s thesis provides bacteria incubation performance to cultivate bacterium for several ratios and its effect on IFT reduction based upon biosurfactant production. Priharto’s thesis performed the core-scale simulation on artificial sandstone core. In this study, this data were used to develop a mathematical model, either a bacteria model or a recovery factor model due to flooding. © IPA, 2014 – 38th Annual Convention Proceedings, 2014