Offshore Hydrocarbon Mapping in Falkland Islands CSEM Program
Offshore Hydrocarbon Mapping plc (OHM) is currently on location with the survey vessel MV Aurelia in the North Falkland Basin conducting a shallow water Controlled Source Electromagnetic Imaging (CSEM) survey for Rockhopper Exploration plc. It is the first survey of this type to be conducted in the Falkland Islands and will be keenly watched by the exploration industry, the Falkland Islands Government and investors alike.
Dave Pratt, OHM's CEO said; " By undertaking CSEM surveys Rockhopper Exploration are progressing exploration in the Falklands, de-risking their exploration prospects ahead of any drilling program and ultimately protecting their shareholders interests.
"In remote locations such as the Falkland Islands OHM's CSEM imaging technology is especially valuable. Mobilizing exploration drilling rigs to such frontier areas, especially at times of very high rig rates, is expensive. As the cost of CSEM surveys is significantly less than drilling, exploration companies are able to investigate many more prospects than would have been the case if drilling was their only recourse"
The data acquisition program is being conducted over a number of prospects in water depths of approximately 150 to 500 meters, using one of OHM's specialized survey crews and incorporating OHM's proprietary EM source and receiver systems.
Although this is the first survey of its kind in the Falkland Islands, feasibility modeling has indicated that the anticipated reservoir scenarios should give a significant EM response.
Before mobilizing for a CSEM survey, the prospect's electromagnetic response is calculated and used to assess the influence of local structure, for example salt or volcanic bodies, on the outcome of a survey. The sensitivity to target parameters such as reservoir thickness, resistivity and lateral extent is examined and the resolution with which these parameters can be determined is quantified. In cases where there are competing geological interpretations of existing data, modeling is used to ascertain to what extent these can be distinguished using CSEM surveying.
Finally, acquisition parameters are optimized for the defined survey objective. The model results are used to determine the source tow and receiver array geometries and source transmission frequencies that will provide the best resolution of target structures and properties.
Only when the modeling process has been completed, can OHM confirm that the technique will provide conclusive indication of the presence of resistive layers consistent with hydrocarbon reservoirs in the prospects modeled.
Once the data is gathered and processed, there are a range of 1D, 2D and 3D inversion algorithms that can be applied to the data along with OHM's innovative diffusive E-field focusing (DEFF) imaging technique, which allows resistivity volumes of the earth to be created.
Dr. Lucy MacGregor, OHM's Chief Scientific Officer commented:
"The North Falkland Basin is a new area for the application of the CSEM technique and as the targets are in relatively shallow water depths, the survey provides us with the opportunity to further demonstrate our recently launched shallow water technique.
"As with all our surveys, we take great care in the survey planning and modelling stage to ensure that the data we do acquire is relevant and capable of being processed and interpreted to give our clients a meaningful answer."
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Company: Rockhopper Exploration more info
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