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PETROMAKS2-Stort program petroleum

Enabling time-lapse 3D CSEM for reservoir management

Alternative title: Reperert 3D CSEM for bruk til reservoar-styring

Awarded: NOK 1.3 mill.

After an oil or gas field is taken into production, there is a need to understand and monitor the changes in fluid distribution inside the reservoir. The extraction of oil and gas combined with the possible injection of water or gas into the field affect the pressure and hydrocarbon saturation. In order to optimize the drainage by planned well production and placement, data from the reservoir must be collected continuously from the operative wells and from surface surveys. The time-lapse seismic technique has been developed from the 1990s and is currently adopted as a very valuable tool for providing information to reservoir management. However, there are still some shortcomings and limitations to what can be achieved. The industry is currently turning to multiphysics approaches that seek to combine seismic with independent measurements to resolve interpretation challenges and give more precise information. The marine controlled-source electromagnetic (CSEM) technique was developed for oil and gas applications during the last 20 years. This technology has now reached maturity and is used routinely when exploring for new field. The recent developments also motivate the use of this technology for reservoir management in the form of time-lapse CSEM. In this project, we will determine how CSEM should be applied to contribute to oil and gas production monitoring and drainage optimization. Since CSEM data have some properties that are distinct from seismic, there is a need to develop specialized strategies for optimal resolution and imaging of changes in reservoir resistivity. The aim is to create software allowing to compare different types of acquisition and imaging strategies. Based on this we will consider realistic models for reservoirs in Norway using computer simulations to demonstrate what the time-lapse CSEM method can contribute.

Due to a severe downturn in the oil and gas services market (caused by the coronavirus crisis and very low oil price) and associated reduction in R&D activites, the project was terminated early. During the limited duration of the project, research results pertaining to the formulation of the time-lapse 3D CSEM inversion problem were obtained. The software implementations were, however, not completed. Parts of the project objectives will transfer to a new project led by NTNU. The current results and plans for demonstrating the feasibility of the time-lapse 3D CSEM method for reservoir management will be made available for the new project. With access to both the EMGS production software (provided by EMGS to NTNU free of charge) and detailed geophysical data for Wisting, we anticipate that it will still be possible to mature the technology motivating future deployment.

This project will enable new applications of controlled-source electromagnetics (CSEM) to production planning and time-lapse monitoring. These applications are motivated by recent technology developments enabling improved resolution imaging as well as identified limitations of current tools for reservoir monitoring. We will develop new techniques for acquisition, imaging, and interpretation relevant to reservoir production planning and monitoring and demonstrate this on two case studies relevant to the geology of of the Barents Sea and the North Sea/Norwegian Sea. Integration with other geophysical data, in particular time lapse seismic and gravity data, will be crucial in the project. Our study will define solutions that address the need for detailed knowledge of production fluid movements in environmentally sensitive areas.

Funding scheme:

PETROMAKS2-Stort program petroleum