Print this pageAdvanced Geophysical Methods for the Exploration and Characterization of Prospects and Fields in Deepwater Angola
Major discoveries and developments over the past years in Angola are concentrated in the deepwater of the Lower Congo basin. This basin is characterized by a prolific petroleum system where some of the main reservoirs consist of turbiditic sands deposited in a slope context with structural control on deposition.
This paper will illustrate advanced geophysical methods used to explore the compressional sub-salt domain and to characterize complex fields discovered in the more conventional translated domain. Both new seismic acquisition and processing methods are considered either to reduce exploration risks or to optimize the production of deepwater fields. Still today and after many years of investigation, a lot of technology is needed to tackle the numerous technical challenges encountered for exploring and developing the Angolan deep waters.
- In subsalt domains the key is seismic imaging. One way to better illuminate the subsalt and near-salt areas is to design and shoot specific wide azimuth seismic acquisition (WATS) and to process the data using up-to-date depth imaging workflows. These workflows use new imaging algorithms (Beam type, Reverse-Time Migration …), new interpretation methods (double salt iteration, anisotropy…) and massive computer resources. The improved imaging technology leads to a better understanding of the salt tectonics, leading to better interpretations of salt bodies, rafted sediments and therefore better velocity models for depth migration. Illustrations and learnings will be given in the presentation.
- To optimize the production and development of Angolan deepwater fields, more and more sophisticated geophysical tools are given to petroleum geologists and geophysicists. One of these tools is 4D seismic and related processed information (inversion and warping data…). 4D data are the geophysical data needed to dynamically characterize the Oligocene highly permeable unconsolidated sandy reservoirs (turbiditic systems associated to several meandering channel-levee and sheet complexes). New seismic acquisition methods are now considered to go one step further for improving the integration of 4D data in the production management of complex deepwater reservoirs: permanent seismic monitoring is investigated as well as the use of new subsea equipment (4C nodes). Illustrations and learnings will be given in the presentation.
AAPG Search and Discover Article #90100©2009 AAPG International Conference and Exhibition 15-18 November 2009, Rio de Janeiro, Brazil