Chalk samples

Ekofisk and Tor Fm. Improved Recovery

We are working to optimize oil production by improving water injection technology. In conventional water injection, seawater is pumped into the reservoir to maintain pressure and push the oil toward the well. Our research investigates how changing the composition of this water may improve efficiency and increase oil recovery. When we regulate the concentration of minerals in the injection water, we achieve both increased recovery and a number of environmental benefits.

Increased extraction with modified seawater

In our research, we test a variety of seawater modifications for injection, particularly investigating desalination and sulphate removal. These compositional changes alter the interaction between water, oil and rock, ultimately providing improved recovery.

In laboratory tests with modified seawater we can extract around 4% more oil, and we continue to develop this work to confirm applicability at large industrial scale.

Reduced corrosion and chemical consumption

A major effect of using injection water containing less sulphate is that less hydrogen sulphide (H2S) is formed in the reservoir, which provides a number of environmental benefits. H2S is a toxic gas and can lead to increased corrosion and scaling, but the modified water injection helps to mitigate against these effects. The bacteria that form H2S do not get the same amount of sulphate as before, and thus their growth conditions are weakened. These modifications help to increase the service life of current infrastructure and thus lower operating costs. Simultaneously, reductions in H2S in the reservoir allow a reduction of the use of other chemicals normally used to remove the gas later in production.

Less CO2 per oil barrel

The increased recovery means that we get more production for the energy used to pump water into the reservoir. In other words, advanced water injection is more energy efficient than conventional water injection, and thus our research contributes to reducing the amount of CO2 emitted per oil barrel produced.

Modelling of fractures

Another part of our research is concerned with creating models that show the distribution of fractures in the reservoir and their influence on fluid flow through geological layers. By gaining a better understanding of the properties of the rock we can further optimize the recovery with modified water. We already have a patented solution for geological modelling, and we are also working on modelling the dynamic effects.

Collaboration

Our research into advanced water injection is done in close collaboration with DUC, creating many synergies. The design of DUC's platforms makes it relatively straightforward to implement our results, as there is already room for the relatively inexpensive water treatment plants that would be installed on the platforms. The collaboration with DUC thus means that DUC would be able to obtain the energy benefits and at the same time have a positive economic effect from the research results.

Collaboration partners

Outcrop Analog studies of Chalk

Iris Fernandez
Iris Fernandes, PhD student at the Niels Bohr Institute at University of Copenhagen, shares how she does research in Computational Geoscience.

Contact

Ulla Hoffmann
Programme Manager
Centre for Oil and Gas - DTU
+45 93 51 13 60
https://www.oilgas.dtu.dk/english/research/work-programmes-and-research/awf-1
3 DECEMBER 2020