Trinidad Basin

Petroleum Systems of Trinidad
Integrated Geochemical Studies of The Columbus Basin and Southern Trinidad

GEOCHEMICAL SOLUTIONS INTERNATIONAL, INC. (GSI) and BASELINE RSOLUTIONS INC. (BRI) have conducted non-exclusive, multi-client studies evaluating petroleum systems of A) the Columbus Basin and B) southern Trinidad, including the Gulf of Paria. The Columbus Basin off the east coast of Trinidad forms the southeastern portion of the East Venezuela Basin. Exploration for hydrocarbons has resulted in the production of more than 2.6 billion bbl of oil from Miocene-Pliocene turbidite sands, and estimates indicate an additional 2 billion bbl of oil and 30 TCF of gas in place. The Columbus Basin has become an important gas province as a result of several discoveries within the last five years, which have nearly doubled Trinidad’s annual gas production.

The sedimentary sub-basins encompassed in the regional study Southern Trinidad include the onshore Southern Basin, the Caroni Basin and the Central Range Area. Nearly 1.5 billion barrels have been produced from this mature petroleum province, primarily from Pliocene and Miocene sandstone reservoirs.

Combined, the two studies have identified and defined the geographic limits of petroleum systems in the region through geochemical analysis of nearly 600 oils and condensates from nearly every significant accumulation and producing horizon. State-of-the-art analytical techniques have been used to evaluate: (1) source facies, (2) thermal maturity, and (3) degree of alteration (biodegradation; migration/fractionation; mixing). Several seafloor oil seeps recovered in piston cores at various deep-water sites were also analyzed and correlated to the known production on the shelf, in order to assess active petroleum systems in these frontier areas. In addition to hydrocarbon fluids, over 100 gas samples from multiple producing horizons in several of the major gas and gas condensate fields were analyzed to determine compositional and isotopic characteristics related to their mode of origin. Source rock data from both public domain and newly-released sources have been compiled and used to assess timing and volumetrics of hydrocarbon generation and migration. The combined results are interpreted in a petroleum system context that defines the principal source rocks and kitchen areas, migration pathways and processes controlling lateral and vertical distributions of gas/condensate/oil in the region.

In the Columbus Basin a regional hydrocarbon generation and migration framework was established using 2D basin models of a regional seismic line. The geochemical data has been integrated with the model results to define regional petroleum systems and assess filling histories and post-generative processes that affect the distribution of gas/condensate/oil in this geologically-complex region. Detailed understanding of these processes has important implications to hydrocarbon exploration in the deep-water blocks to the east.

Fluid and seep samples were characterized through a detailed analytical program including gas chromatography, stable carbon isotopes, and quantitative biomarker analysis of saturate and aromatic fractions by gas chromatography/mass spectrometry (GC/MS). Detailed biomarker analyses were performed on selected samples using high-resolution GC/MS/MS (MRM). Gas compositions were determined using standard chromatographic techniques and isotopic compositions of individual gas components were determined using gas chromatography/ isotope mass spectrometry (GC/IRMS).

Deliverables for these studies consist of printed data volumes summarizing the analytical results in addition to interpretative final reports. The final reports contains key data maps as well as a synthesis and interpretation of all results including oil-oil and gas-source correlations, thermal maturity assessment, and field reservoir compartmentalization. All geochemical data is also provided in digital format in a database contained on CD. Both projects are complete and available for immediate delivery.