Laboratory studies of rice bran as a carbon source to stimulate indigenous microorganisms in oil reservoirs

Chun-Mao Chen,Qing-Hong Wang,Jung Bong Kim,Qing X Li,Brandon A Yoza,Jin-Ling Wang,Jing Wang

doi:10.1007/s12182-016-0104-7

Abstract

There is a great interest in developing cost-efficient nutrients to stimulate microorganisms in indigenous microbial enhanced oil recovery (IMEOR) processes. In the present study, the potential of rice bran as a carbon source for promoting IMEOR was investigated on a laboratory scale. The co-applications of rice bran, K2HPO4 and urea under optimized bio-stimulation conditions significantly increased the production of gases, acids and emulsifiers. The structure and diversity of microbial community greatly changed during the IMEOR process, in which Clostridium sp., Acidobacteria sp., Bacillus sp., and Pseudomonas sp. were dominant. Pressurization, acidification and emulsification due to microbial activities and interactions markedly improved the IMEOR processes. This study indicated that rice bran is a potential carbon source for IMEOR.

Highlights

Increasing demand for crude oil is promoting the development of oil extraction technologies
This study indicated that rice bran is a potential carbon source for indigenous microbial enhanced oil recovery (IMEOR)
According to the Box–Behnken experiments (Table 2) and subsequent response surface regression analysis (Fig. 3), the optimal bio-stimulation conditions were estimated as 3.36 g/100 mL of rice bran, 0.075 g/100 mL of K2HPO4 and 0.076 g/100 mL of urea

Summary

Introduction

Increasing demand for crude oil is promoting the development of oil extraction technologies. Indigenous microorganisms, which naturally inhabit oil reservoirs, show a greater metabolic activity than exogenous ones due to their long-term adaptation (CastorenCortes et al 2012; Lazar et al 2007). Indigenous microorganisms activated MEOR (IMEOR) has greater efficiency than using exogenous ones (Yao et al 2012; Zhang et al 2012). Gases can pressurize the oil reservoir and reduce the viscosity of crude oil (Kobayashi et al 2012; Spirov et al 2014). Acids may increase carbonate rock porosity and permeability, thereby promote the exudation of remained oil (Sen 2008). The multiple effects of various metabolites improve oil flooding and enhance crude oil recovery

Objectives

Methods

Results

Discussion

Conclusion