Thermal EOR has been applied in different reservoirs in Oman to maximize the production from heavy oil prospects. PDO consider the highest HSE standard in their field operation to protect people and the integrity of the assets. In thermal EOR one of the highest HSE and risk integrity is the drastic increase of acid gas production mainly (H2S and CO2).
Historically, the quantification of the acid gas development in thermal EOR developments has been challenging, either leading to underestimation of the acid gas levels or overdesigning the material type with huge cost associated which impact the commerciality of the project especially at the current low oil price. Thus, improvement of the thermal souring prediction capabilities is required for the risk assessment and fit for purpose material selection rather than exotic option.
This work shows the results from an integrated subsurface and surface engineering collaboration to define the geochemical sources of souring in the thermal projects and to quantify the H2S/CO2 profile over the life cycle of the project. For the first time in PDO, a souring prediction workflow was developed and validated by coupling the reaction transport models with reservoir engineering dynamic models. The outcomes are used to define a safe operating envelope and move the operating mindset to be a proactive approach in managing the thermal souring risk.