Page 33: of Offshore Engineer Magazine (Nov/Dec 2025)

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he handling of produced fuids, a mixture of oil, water, and gas, is essentially a huge waste of energy. Water production is primarily caused by channeling and uneven drainage along the

T wellbore resulting from mobility contrasts within the reservoir. The water is a worthless byproduct of production, and its removal from reservoirs causes a loss of pressure that lowers production if it is not countered by reinjecting more water back in. This in turn increases energy consumption, as reinjection pumps are usually the second-largest energy consumers in offshore oil and gas production after gas compressors.

One of the goals of the LowEmission Centre, an eight- year research program managed by SINTEF, is to develop solutions that reduce the energy consumed by these pro- cesses. While focused on the Norwegian Continental Shelf, the solutions are anticipated to bring benefts globally.

There is a balance between

Senior Research Scientist, Dr. Heiner Schümann, says maintaining sufficient reservoir energy effciency is not only a climate measure but also pressure and reducing an economic one. He is co-author in a recently published study, along with PhD candidate Handita Reksi Dwitantra selective inflow.

Sutoyo and Prof. Carl Fredrik Berg, that analyzed the bal- ance between high hydrocarbon demand and the impera- – Handita Reksi Dwitantra Sutoyo tive to reduce CO2 emissions by estimating how drainage strategies change under varying economic parameters.

Using model simulations that included both net pres- ent value (NPV), yield, energy consumption, and CO2 emissions, they concluded that increasing gas prices favor reducing reservoir pressure below the bubble point pres- sure, thereby releasing solution gas and leaving oil in the reservoir. Although lower reservoir pressure reduces the energy required for injection, the resulting increase in gas production necessitates more energy for gas compression, ultimately leading to higher emissions when gas prices rise relative to oil prices.

For greenfeld scenarios where well design matches pro- duction volumes, the impact of a CO2 tax is limited, lead- ing to a single optimal drainage strategy. In this case, a non-linear relationship was evident between the reduced production and emissions. For increasing tax levels there were diminishing returns on lower emissions, refecting reduced opportunities for emission reduction by changes in the drainage strategy. Some increments in tax rate will therefore have negligible impacts on drainage strategy, re- ducing proftability with negligible emission reduction.

In contrast, drainage strategies for less energy-effcient

Energy loss rate per mechanism in the production facilities are more dependent on variations in CO2 tax and stream of a studied NCS field. Major energy losses are caused by lifting and transporting produced water. oil and gas prices. Under-saturated oil reservoirs where

NOVEMBER/DECEMBER 2025 OFFSHORE ENGINEER 33