Marjorie Levy1, Alan Reed1, June Gidman1, Elizabeth Schwarze2
(1) Chevron Petroleum Technology Company, San Ramon, CA
(2) Chevron Overseas Petroleum Company, Maracaibo, Venezuela
ABSTRACT: Reservoir Modeling of the Stratigraphically Complex Boscán Field
Boscán Field, located in the Maracaibo Basin of Venezuela, produces from the upper Eocene, Boscán (Misoa) Formation. The Field currently produces 115,000 BOPD of 10º API oil under primary drive; cumulative production is over 1 Billion BO. Planning for continued development of the Field requires the construction of geological/geostatistical models for simulation of Improved Oil Recovery processes.
Boscán Field is a combination structural/stratigraphic trap. The reservoir sands were deposited in a tidal-dominated depositional setting. Boscán Field has a complex stratigraphic framework, the interpretation of which is made particularly difficult by the 1-kilometer well spacing and the lack of modern logs. Numerous incised valleys create cross cutting stratigraphic layers, making well correlation very challenging.
A facies-based, geocellular model was constructed for the northern portion of the field. Facies were interpreted qualitatively in Geolog(tm) and converted into a numeric log that was loaded into GOCAD(tm) for geostatistical simulation. The model captures the interpreted cross-cutting stratigraphic relationships but does not incorporate any of the minor faulting within the field. Depositional facies were modeled within the complex stratigraphic layering, and then the facies regions were populated with reservoir properties.
Reservoir properties were derived from data from two recent cores. A relationship was established between the deep resistivity (RT) and permeability. In this portion of the field all reservoir sands are well above the oil/water contact mitigating any potential complications due to fluid effect. Porosity was directly transformed from the created resistivity-based permeability log. Saturations were initialized based on capillary pressure data which was converted using a Leverett J function.
AAPG Search and Discovery Article #90906©2001 AAPG Annual Convention, Denver, Colorado