Print this pageC. L. Farmer1, E. R. Shaw2, T. K. Burch1
(1) BP, Houston, TX
(2) BP Trinidad, Port of Spain, Trinidad and Tobago
ABSTRACT: The Red Mango Area - discovery and delineation of a 3 TCF gas field, Columbus Basin, offshore Trinidad
The Columbus Basin of Trinidad is one of the largest emerging gas provinces in the western hemisphere. Major gas fields include Immortelle (1967), Cassia (1983), Mahogany (1994), Flamboyant (1994), Amherstia (1995), Corallita (1996), and Kapok (1997-98) together totaling over 15 TCF of recoverable reserves. The most recent Red Mango discovery (2000) adds another 3 TCF.
Recent gas discoveries in Trinidad result from several extensive 3D seismic surveys which image complex, faulted, stacked reservoirs. Conformance of bright amplitude anomalies to structural closure and "flat spot" detection are key techniques for mapping gas reservoirs. All of the Red Mango reservoirs exhibit bright amplitude anomalies that conform to structure. Flat spots in the thicker horizons correspond to fluid contacts. Excellent seismic resolution of mapped reservoir horizons yielded a 90% pre-drill chance of success for Red Mango.
The discovery is located in a graben between a major east dipping listric normal fault and a west dipping antithetic normal fault. Strike closure is related to a deep transpressional ridge that pre-dates normal faulting. The anticlinal crest is cross-cut by normal faults. Reservoirs are laterally extensive Pliocene sands deposited in a shallow marine shelf environment. Depths range from 6400 to 13400 feet. Porosities ranging from 20-33% can be predicted predominantly as a function of depth. Petrophysical analysis emphasizes laminated pay and calibrates porosity to cores.
Trinidadian gas is an economic reality following the 1999 completion of a liquefied natural gas plant. Continued exploration is planned to expand the natural gas resource base.
AAPG Search and Discovery Article #90906©2001 AAPG Annual Convention, Denver, Colorado