Paraná Basin

Round 2 Surface Coring Survey

A new surface geochemical study to detect deep subsurface hydrocarbons in the onshore Paraná Basin, Brazil is proposed by GEOCHEMICAL SOLUTIONS INTERNATIONAL, INC. (GSI). It is one of several surface geochemical projects being developed by GSI that evaluate the hydrocarbon potential of onshore Brazilian sedimentary basins. The proposed study will collect and analyze surface samples in block BT-PR-4 offered as part of Brazil's Second Oil and Gas Licensing Round sponsored by the Agência Nacional do Petróleo (ANP).

Onshore geochemical surveying is one of the oldest and most successful surface prospecting methods. It is based on the fundamental premise that light hydrocarbons generated from deep subsurface sources can migrate vertically to surface and near surface soils. The migrating hydrocarbons are manifested as chemical, physical or biological anomalies in the soils, which can be detected using a variety of means. When integrated with surface geological structures derived from analysis of satellite images, this approach represents a powerful tool for evaluating the exploration prospectivity of different regions within a basin, which has been used successfully in several of the onshore Brazilian petroliferous basins.

The Paraná Basin is located in south-central Brazil, extending into northern Uruguay, northeast Argentina and eastern Paraguay and Bolivia. The Brazilian portion covers an area of 1,100,000 square km and encompasses parts of the Rio Grande do Sul, Santa Catarina, Paraná, São Paulo, Goiás, Minas Gerais, Mato Grosso and Mato Grosso do Sul states. Recent natural gas discoveries announced by Petrobras in block BPAR-10 (adjacent to the block offered in Round-2) indicates the existence of a proven petroleum system.

A total of 634 soil samples have been collected along a grid. The sampling depth ranged from 1.2 to 1.5 m below the surface, in order to minimize interferences from biologically-derived hydrocarbons that occur naturally in the soils. Landsat® satellite images were acquired and processed in order to evaluate the relationship between fault zones (possible pathway of gas) and the incidence of gas anomalies. Soils were analyzed to determine the content and composition of "free" light hydrocarbon (C1-C5) gases at the Center of Excellence in Geochemistry (CEGEQ) in Rio de Janeiro, and at the BGR Laboratories in Hanover, Germany. These data are treated statistically in order to identify "outliers" indicative of geochemical anomalies.

Value-added products included as part of the deliverables include 1. Samples Logs with location, sample depth, soil type, soil color, soil humidity, location relief and vegetation for each site. 2. Geochemical Data for 634 soil samples documenting light hydrocarbon concentrations and composition. 3. Maps of sample locations (including interpreted surface faults) and various parameters indicative of geochemical anomalies. 4. Data CD-ROM with database (MS Access 97) containing all analytical results and sample log information. 5. Interpretative Report in both printed and HTML formats describing the locations and magnitude of geochemical anomalies.