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C. Randy Smith1,
Hal H. Macartney1
(1) Texaco, Inc, Houston, TX
Abstract: Impact of complex turbidite stratigraphy on field development -- Campos Basin, Brazil
The discovery of a large oil field does not always translate into an easy profit, especially in deep water. Field development can pose many challenges to making a project economically viable. Stratigraphic complexity is a common issue, especially when compounded by unfavorable fluid properties.
Frade Field is an undeveloped oil accumulation in the northern Campos Basin in 1150 meters of water. Petrobras discovered the field in 1986. Deepwater clastic reservoirs of Late Cretaceous through Miocene age contain reserves of up to 300 MMBOE. The faulted anticlinal structure has been evaluated by only two wells at present.
Much of Frade's oil is in a series of Miocene turbidite sands deposited as part of a confined slope fan system. Seismic imaging indicates a multi-leveled architecture of stacked and nested channel features. The complex reservoir geometry presents many hurdles to efficient oil extraction.
Because the oil is moderately high viscosity (18 cp), horizontal wells typically would be needed to establish economic production rates. However, horizontal drilling cannot adequately drain multiple levels of sands. Highly angled wells or multi-lateral horizontals are potential alternatives. Because water injection is required for maximizing recovery, reservoir connectivity is also a major issue.
The need for sophisticated simulation models places a strong emphasis on reservoir characterization. Three-dimensional visualization, seismic attribute analysis, and geostatistical modeling have facilitated replication of the slope fan architecture in reservoir models. Simulation allows various development scenarios to be tested in the pursuit of an optimal drilling plan.
AAPG Search and Discovery Article #90914©2000 AAPG Annual Convention, New Orleans, Louisiana