DETECTION AND INFLUENCE ASSESSMENT OF SULFATE REDUCING BACTERIA

Abstract

The present study is related to the environmental and engineering problems caused due to the presence of sulfate reducing bacteria in produced water of Ghani oilfield. Ghani oilfield has two reservoirs namely Farrud (sweet crude) and the Gir/Fatcha (sour crude). The Ed Dib Field is located just east of the Ghani Field and offers significant (sour crude) development potential. The sour crude processing facilities are located in Zenad, just north of the Ghani Field, where all sour crude produced in Ghani, Ed Dib and smaller fields is gathered and processed before it is blended with Ghani's sweet crude for export through RasLanuf Terminal. In recent years, two water injection projects were completed for pressure maintenance in the Farrud and the Gir reservoirs. The injection water is derived from a saline water source just west of the Ghani Field. In overall Ghani oilfield has three different kind of water. The water samples from these locations were found to be contaminated with sulfate reducing bacteria.

The sulfate reducing bacteria can be eradicated from Ghani oilfield water by using biocide chemicals. Three different classes of chemicals namely JOF CIDE 5692 (glutaraldehyde based chemical), JOF CIDE 5225 (quaternary ammonium based chemical), and JOF CIDE 5622 (phosphonium based chemical) were obtained from Jowfe Oil Technology Company and evaluated for their biocide killing performance. The time kill method was used for determining minimum inhibition concentration (MIC) value. From the results obtained, the best performance showed by JOF CIDE 5622. JOF CIDE 5692 also showed satisfactory performance but JOF CIDE 5225 was not performed well for eradication of SRB in Ghani field.