Rawwater News

Rawwater icon

Introducing Reservoir Souring and Management to ICorr Aberdeen

With the cost of oilfield souring control rumoured to consume as much as one-third of typical production budgets, it is essential for operators to be able to accurately assess whether or not microbiological souring is likely to occur in their reservoirs – and to understand how to treat it cost-effectively.

At the recent ICorr (Institute of Corrosion) Aberdeen Technical Event on Tuesday, 29th October 2019, Matt Streets, one of our senior project officers, introduced delegates to the causes of oilfield reservoir souring, the key requirements that enable souring to take place, the importance of souring forecasting – and the various souring control & mitigation strategies that can be put in place.

Successfully extracting oil throughout the life of a reservoir requires additional downhole pressure. Ironically, it is the process of pumping in water to maintain pressure during secondary recovery that can introduce sulfate-reducing (souring) bacteria into a sweet crude oil environment. Where conditions are right, the result is increasing levels of sulfur in the oilfield reservoir. However, as it can take several years of production before increased souring is detected in crude output, the challenge for producers is to identify any risk of souring early enough to allow economical treatment.

More expensive to refine, as it requires the use of corrosion-resistant topsides equipment and costly chemical dosing regimes, sour crude typically contains in excess of 0.5 percent sulfur which characteristically takes the form of toxic, highly corrosive and foul-smelling hydrogen sulphide (H2S) gas.

Matt’s presentation also included an introduction to our advanced UK-based research facility where specially constructed pressurised bioreactor columns containing sand, seawater and crude oil - and inoculated with oilfield bacteria - are used to evaluate microbiological souring in simulated reservoir pressure and temperature conditions, and to determine the efficacy of various injection chemistries.

Matt also covered DynamicTVS (Thermal Viability Shell) – our software modelling programme that uses operational, planning and survey data from all phases of oil extraction to predict hydrogen sulphide production over the lifetime of a reservoir and forecast its propensity to sour in advance of well completion.

Following his presentation, Matt  (left of photograph) received a Certificate of Appreciation from ICorr Aberdeen branch chairman, Stephen Tate. For a copy of Matt’s presentation and to learn more about the causes of oilfield reservoir souring, email: info@rawwater.com