AAPG ANNUAL CONFERENCE AND EXHIBITION
Making the Next Giant Leap in Geosciences
April 10-13, 2011, Houston, Texas, USA
The Impact of Stratigraphic Interpretation on Lucapa Field Development Planning, Deepwater Angola
(1) Chevron Africian and Latin America Exploration and Production Company, Houston, TX.
(2) Chevron Energy Technology Company, Houston, TX.
The challenge of planning the development of turbidites of deepwater fields in Angola is being aided by the application of 3D volume interpretation and visualization techniques to reduce uncertainty in reservoir characterization. Understanding the stratigraphy of deepwater fields offshore Angola can be challenging due complex geology combined with seismic data quality issues related to the presence of salt domes and proximity to the paleo Congo Canyon.
The Lucapa field, discovered in 2006, is a combination structural-stratigraphic trap composed of reservoirs characterized as a deepwater mid-slope channel deposits in the Middle Miocene section. The approach taken to unravel Lucapa field complex stratigraphy was to map in areas off-structure where seismic data quality is good. Mapping where confidence in the interpretation was high helped constrain the stratigraphic framework in the area of interest on structures where seismic data quality is poor. Volume visualization techniques such as optical stacking and seed picking in flattened seismic volumes were used to delineate channel complexes and correlate wells.
3D seismic visualization, integrated with a turbidite hierarchical approach to geological modelling, facilitated prediction of complex-scale facies distribution, selection of appropriate analogs, prediction of reservoir distribution at the well bore and away from the wells, and prediction of reservoir connectivity. By developing the stratigraphic framework in areas of good-quality data adjacent to the field, we have been able to fill in much-needed detail between wells in the field, which is especially important given our sparse pre-development well control and stratigraphically complex turbidite channel systems. The resultant stratigraphic architecture is more accurate and precise than a traditional lithostratigraphic well-correlation and seismic interpretation would have produced.
Establishing the seismic stratigraphic framework for the Lucapa field had impact on the development planning and allowed the multidisciplinary team to: (1) reduce the uncertainty in oil in place estimation, (2) optimize well placement (producers and injectors), (3) reduce reservoir risk during appraisal and development wells planning, (4) define the aquifer size with impact on water flood design, (5) establish different scenarios of reservoir connectivity with impact on production profiles and (6) define the reservoir basis of design for field development.