Seal Characterization by Integrated 3D Seismic and Well Data: CO₂ Storage-Casablanca Field (Offshore Spain)

Claudia Bertoni¹, Tomas Vallaure¹, Adela Herra¹, and Koldo Gorocica^2
1Repsol-YPF, Madrid, Spain
²Repsol-YPF, Madrid, Spain

The mature Casablanca oil field is a karstified and fractured reservoir located in the NW Mediterranean Sea (offshore Spain). A viability study of CO₂ injection and long-term safe storage in this field is currently under evaluation by Repsol-YPF in collaboration with the IFP and within the European Union CASTOR Project.
This work uses integrated seismic and well data for the definition of the Static Seal Model of the Casablanca field, and focuses specifically on the Seal Integrity technical risk factor. The main aim is the definition of the sealing rocks architecture in order to identify any potential leaking system for the stored CO₂ in the Casablanca reservoir. To achieve this objective, semi-regional 3D seismic and well data have been interpreted over the Casablanca field and the Tarragona Trough. Eight recently acquired and vintage seismic surveys have been used to produce a detailed semi-regional seismic interpretation and attribute analysis.
The first results evidence a potential CO₂ leaking system at the western faulted flank of the Casablanca field. The components of this system are: 1) Messinian channelised sandstone bodies, 2) Miocene Castellon Sandstones topsets, and 3) an up-to-the-seabed fault system located 20 km west of the field. We will present and discuss the impact of each of these components on the viability of the long-term CO₂ storage project. Ultimately, this study is an example of how 3D seismic analysis can be routinely used in an integrated workflow for the risk evaluation of CO₂ management projects in structurally complex mature reservoirs.

AAPG Search and Discovery Article #90072 © 2007 AAPG and AAPG European Region Conference, Athens, Greece