Bacterial Treatment to control SRB & H2S Levels in Oilfield Application
- Industry: Oilfield Production
- Products Used: CWS 1122
- Location: UK Oil Producer
THE PROPOSITION
The treatment was designed to reduce the SRB numbers within the well and as a consequence reduce the H2S levels. This reduction would be brought about by the cultivation downhole of competitive Nitrate Reducing bacteria, which pose no detrimental effect to oil production or associated activities.
THE TREATMENT PROCESS
The first trial was carried out on well that fell within the suitable characteristics range. The H2S and SRB levels were quickly brought under control, with H2S levels registering negligible levels.
Chemiphase undertook extensive well testing and pinpointed high levels of Sulphate Reducing Bacterial strains within the well formation. During the early months of 2011 a bacterial programme was designed which encompassed a Chemiphase formulated bacterial product and a unique nutrient package. These products were applied to two of the worst effected wells.
The treatment was designed to reduce the SRB numbers within the well and as a consequence reduce the H2S levels. This reduction would be brought about by the cultivation downhole of competitive Nitrate Reducing bacteria, which pose no detrimental effect to oil production or associated activities.
THE RESULTS
The above graph shows the extent of the H2S reduction.
The above graph shows the extent of the SRB number count
In the same time period the NRB numbers had increased from a zero to 80,000 – 100,000 cfu/ml.
THE CONCLUSION
At the commencement of the Chemiphase treatment programme SRB numbers were in excess of 100,000 cfu/ml with H2s levels ranging from 800 to 1450ppm. After an brief shut in period and initial operating period the SRB numbers had reduced into the region of 0-10 cfu/ml with the H2S readings being negligible at between 0 and 0.2 ppm.