Facies comparison from bank margin to deep water basin: Golden Lane carbonate depositional system, southern Gulf of Mexico

Chen, Jiajie (Jeff), Scott Pickford, Houston, TX, USA; C. A. Aduna; F. Sanchez Lu, Jaime Patino, and Miguel Olivella, Residencia de Exploracion Poza Rica, PEMEX, Mexico

Abstract

Located in the southern Gulf of Mexico, the Golden Lane area comprises a complete carbonate facies assemblage, from lagoon interior and bank margins to slope and basin talus deposits. Using an integrated approach, we analyzed the depositional processes that directly influenced the accumulation of reservoir rocks in the Golden Lane area. Typically, comparison of two deep wells that have penetrated into the basement, Atun-502 and Triton-1, has revealed important information regarding the variations of depositional environment in the study area. Cores from the Atun-502 well are mainly composed of grainstone; some wackestone and packstone indicate a post-reef or lagoon environment. On the other hand, Triton-1 was drilled on the slope of the Golden Lane carbonate system, to the Tamabra Formation, similar to slope deposit in clastic environment. The lithology in Triton-1 is characterized by large texture of intraclasts, rock fragments, pellets, pelloids, and bioclasts, and significant amount of matrix, evident of talus facies. Understanding the facies difference is important in order to define various reservoir models for the oil fields in the Golden Lane area. Another important observation is that cyclic features are more important in the Triton-1 well then the Atun-502 well. One explanation is that the deposition of deep basin carbonate talus has been influenced significantly by different modes of sediment input due to the variation of sea-level cycles on the bank margins. This result may provide additional information on the response of carbonate system to sea-level variations.