Deepwater
Exploration: Columbus Basin Offshore Trinidad
Bhajan, Jeawan1,
Alicia Gargee2, Robert Marksteiner3, Shannon Cheree' Stover4, Kelley Latter5 (1)
BP Trinidad and Tobago, Port of Spain, Trinidad and Tobago (2) BP Trinidad and
Tobago LLC, Port Of Spain, Trinidad and Tobago (3) BP Americas, Houston (4) BP
Sunbury, London, United Kingdom (5) Amerada Hess, Houston, TX
Trinidad has a long and
successful history of hydrocarbon exploration, dating back to the early
twentieth century. In an effort to arrest declining production, the State has
regularly awarded blocks for exploration through the competitive bidding
process. During the period 1996 to 2000, in an attempt to extend exploration
into frontier areas, the State licensed six deepwater blocks in the Columbus
Basin off the island east coast. Eleven wells have been drilled in these
blocks, all of which failed to discover commercial volumes of hydrocarbons. The
objectives of these wells were Middle Pleistocene to Lower Pliocene channel
levee systems deposited in a middle to upper slope
setting. Container geometry varied between four way closures, over which
channel systems were draped, and combination structural/stratigraphic
traps. These prospects were predicted to be charged with hydrocarbons generated
from the same aged Middle to Late Cretaceous source rock that has generated
hydrocarbons in the Eastern Venezuela Basin. Reservoirs were
predicted to have some lateral extent and were mapped unto bleed-off
structures; hence effective stress and column heights were not expected to be
high risk elements. Although all the elements necessary for a working petroleum
system were predicted to be present, these wells failed to discover
hydrocarbons in commercial volumes. This paper reviews the results of these wells,
discusses the failure mode and examines the implications on the continued
deepwater exploration in the Columbus Basin