Integrated study of reservoir souring in chalk reservoirs

Ali Mahmoodi: Reservoir souring, simulating how tiny bacteria live hundreds of meters underground and how it affects our lives

There are communities of a variety of microorganisms living in oil and gas reservoirs, hundreds of meters underground. An especially important type of these microorganisms are called Sulfate Reducing Bacteria (SRB), which consume sulfate among other things and produce hydrogen sulfide (H2S). This process, referred to as reservoir souring, is an unfavorable process for us due to several reasons. First, H2S is a highly corrosive gas and thus, when moved into the wells along with oil, it causes serious corrosion challenges, which in turn increase operational costs of producing oil. Second, H2S is a toxic gas, meaning it can create severe health problems for the crew if leaked out of the system. Third, this gas also has negative impacts on the natural environment. Other than being toxic for animals and even plants, H2S is also a fire danger. Moreover, if leaked into the groundwater or surface water, it changes the acidity of the water, altering the habitats of the animals or microorganisms. For these reasons, among others, there is a need to comprehend our understanding of SRB activities inside oil and gas reservoirs with the purpose of reducing the amount of generated and produced hydrogen sulfide.

In order to fully understand and mitigate the processes resulting in the generation of H2S in underground oil reservoirs, we need to be able to simulate reservoir souring and study its impacts and mitigation at the reservoir scale. In this project, we are integrating mathematical models at different parts of the system in order to be able to simulate multi-phase (oil/gas/water) fluid flow and reservoir souring inside the porous media combined with its impacts on the wells and flow lines in terms of corrosion and scale precipitation. Performing such a study, not only benefits this field of industry and the natural environment, but also has notable uses in other fields. In groundwater studies, the ability to study microbial activities and chemical processes, together with fluid flow and transport of chemical components is vitally important. Specialists in these fields can make use of such a simulator for more accurate, real world simulations. Furthermore, in geothermal energy production, the effect of temperature alterations on the chemical processes, ecology of microorganisms, and the resulting well/flow line integrity and safety implications are of paramount importance, which can be done with such a simulator.

We dream of a secure and safe path toward sustainability, which is reducing the environmental impacts of oil and gas operations as well as clearing the way for renewable alternatives.

PhD project

By: Ali Mahmoodi

Section: Centre for oil and gas

Principal supervisor: Hamid M. Nick

Co-supervisors: Karen Louise Feilberg

Project title: Integrated study of reservoir souring in chalk reservoirs

Term: 15/07/2020 → 14/07/2023


Ali Mahmoodi
Research Assistant
DTU Offshore
+45 50 26 24 57


Hamid Nick
Senior Researcher
DTU Offshore
+45 93 51 14 97


Karen Louise Feilberg
Senior Researcher
DTU Offshore
+45 93 51 14 20