Rawwater Engineering Company Ltd / Early Oilfield Reservoir Souring Forecasting Provides Operators with Greater Insight

A recent enhancement to Rawwater’s industry-leading DynamicTVS© predictive software modelling program, for the forecasting of oilfield reservoir souring, means operators will now be able to gain a good indication as to whether or not their reservoirs are likely souring candidates in advance of full reservoir modelling and commencement of production. Wherever the potential for future souring is found, it will enable mitigation strategies to be considered much earlier than previously, with the potential to save significant sums over the operational life of an asset.

Advice at the earliest stages of planning

“We are now able to provide operators with guidance regarding the likelihood of future souring occurring at the very earliest stages of field planning and development, well before production commences from a new discovery,” comments Rawwater Senior Project Officer, Matt Streets. “This service has already been used by a leading oil operator with assets in the North Sea and has provided them with valuable insight into future microbiological souring within their reservoirs in the absence of a full reservoir flow simulator.

“Our DynamicTVS© souring database is sufficiently large that, using known field parameters from the asset in question, key aspects of microbiological reservoir souring can be teased out, enabling Rawwater to provide a well-considered qualitative forecast as to whether or not the reservoir in question presents a low, intermediate or high souring risk at very early planning and development decision gates,” adds Matt Streets.

“At a later date, say six months hence, when the full reservoir simulator is up and running, and the simulated injection and production profiles have been determined, we can then complete a full reservoir souring forecast using DynamicTVS©, enabling a quantitative forecast with absolute confidence whether or not microbially induced souring will occur and, if so, to what extent. This information will underpin our earlier findings and enable timely mitigation strategies to be put in place.”

Rawwater’s DynamicTVS© predictive software modelling program uses operational, planning and survey data from all stages of oil production, from any temperature and pressure conditions to generate future profiles of hydrogen sulfide (H₂S). It is also supported by data from Rawwater’s use of specially designed crude oil-wetted pressurised bioreactors, operated at pressures and temperatures that simulate near wellbore and deep reservoir conditions in water-flooded reservoirs, to identify whether or not microbiological activity will result in the creation of sufficient levels of hydrogen sulfide to cause souring. Only last year, Rawwater’s pressurised bioreactor facility amassed the equivalent of 500 years’ worth of oilfield souring data – further extending what was already believed to be the world’s largest oilfield reservoir souring dataset.

Oilfield reservoir souring can cause corrosion of topsides’ equipment, leading to risk to the environment, a health and safety risk to personnel, increased cost of production and, therefore, adversely impacting reputation and oil revenues.