The Sabaneta Gas Discovery: A Carbonate Shoal Buildup Trend in the Mature Barinas Basin
Hernandez, Rodolfo1; Kerans, Charlie; and Aleman, Antenor
Some of the world’s most important carbonate reservoir systems are found in foreland basin settings. A wildcat drilled in the southern part of the Barinas foreland basin of Venezuela has tested a new play concept in a Middle Eocene reefal platform in the Masparito Member of the Gobernador Formation. Although the total reserves for this discovery have not been fully evaluated, and the IPR is 1.3 MMCFGD and 35 BCD. This result has significant impact in being the first carbonate discovery in the Tertiary of the Barinas Basin, and has implications for the time-equivalent Guarico (Peñas Blancas Fm.) and Maturin (Tinajitas Fm.) foreland basins.
The Masparito Member overlies a forced regressive siliciclastic shelf of the Gobernador Formation, representing a significant increase in accommodation that leads to development of isolated buildups of up to 60 m thickness on the seaward margin of this shelf. The lower 20 m of the Sabaneta Platform is characterized by mud-dominated carbonates with porosities below 10 percent. Localized development of coarse crystalline hydrothermal dolomite locally improves reservoir quality of these lower mud-dominated facies. Above this, a complex of higher-energy larger foram-coralline algal rudstones/floatstones formed a distinct non-rimmed bioconstructional platform of 8 km diameter. The possible kitchen for this gas accumulation is located near the frontal thrust along the Sipororo, Barrancas and La Yuca gas field trend. The migration fairway is suggested to be through the sand-dominated forced regressive Gobernador Fm.
AAPG Search and Discovery Article #90166©2013 AAPG International Conference & Exhibition, Cartagena, Colombia, 8-11 September 2013