(1) Shell Deepwater, 2288 GD Rijswijk, Netherlands
(2) Shell EPT
Abstract: Bonga field - A New Deepwater Giant
The Bonga field development is located offshore Nigeria, OPL212, in 1000 m water depth. In 1995, the Bonga-1 discovery well discovered high-quality crude oil in unconsolidated, Miocene, deepwater sands, having high porosity and permeability. The development plan includes subsea wells tied to an FPSO, a gas export pipeline tied back to an onshore LNG facility via a shallow water platform, and minimized flaring.
In addition to the discovery well, three additional appraisal wells and two sidetracks have been drilled on Bonga from 1996-1998, and confirm excellent correspondence of seismic attributes with hydrocarbon-bearing sands. Seismic techniques such as 3D volume interpretation and seismic inversion aided exploration and appraisal well targeting and estimates of in-place volumes and uncertainty ranges.
The traps for the Bonga reservoirs comprise updip fault seals, and lateral stratigraphic edges. The initial development targets five reservoirs, all of which have channel components. Experience has shown that deepwater channel reservoirs are prone to surprises, including perched water and gas levels, and highly variable connectivity. The final well count and facility size was tested against many possible scenarios of geologic heterogeneity using details from seismic volume interpretation and outcrop analogues for guidance. Effective reservoir properties and connectivity scenarios were modeled during the reservoir simulation phase.
The drilling and development program is phased over nine years, allowing learning to be gained from the reservoirs as they are developed. Additional in-field and near-field targets will be appraised during development, to extend the production plateau and mitigate any downside outcomes.
AAPG Search and Discovery Article #90914©2000 AAPG Annual Convention, New Orleans, Louisiana