Reservoir Characterisation by Integrated Seismic and Electromagnetic Remote Sensing

The marine controlled source electromagnetic (CSEM) survey method is rapidly gaining acceptance as a geophysical exploration tool for the offshore oil and gas production industry. By determining the electrical resistivity within seafloor geological structures, the CSEM technique can dramatically reduce the risk of drilling dry exploration wells. In this project we propose to extend the application of CSEM to reservoir appraisal and monitoring, through the development of survey geometries and data analysis techniques that optimise the sensitivity of the method to 3D structures, and any changes in them. We shall also seek to integrate the interpretation of CSEM and seismic data, to more fully characterise reservoir properties. The overall objective is to develop methodologies that will allow CSEM to be applied to the mapping of small or incremental hydrocarbon reserves; to accurately monitoring existing reserves during production to optimise recovery; and to monitoring the storage of CO2 in geological sequestration projects. Specific problems of immediate importance to the UK oil and gas industry that the project will address are: Detecting small resistivity anomalies. This will allow small incremental or additional hydrocarbon reserves in 'brownfield' sites to be indentified and quantified. Remote resistivity monitoring of reservoirs. By accurately monitoring the changes in resistivity structure of a reservoir across its full lateral extent during production, water breakthrough can be identified and mitigated to optimise recovery. Integrating results from CSEM surveys with existing seismic information to more fully characterise reservoir content and its changes over time. Monitoring changes in hydrocarbon saturation and distribution within the reservoir during production will again help to optimise production. Evaluation, monitoring and verification of geological CO2 sequestration projects. There are few (if any) remote sensing methods capable of monitoring CO2 content and distribution during injection. This project will investigate solutions to this problem, using the CSEM method to track and monitor CO2 following injection.