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Introduction
- The pre-salt hydrocarbon reserves are located between 5000 and 7000 metres deep in ocean waters (offshore), off the coast of the states of Sao Paulo, Rio de Janeiro and Espirito Santo.
- To reach these deposits it is sometimes necessary to cross 2 kilometres of ocean, 1 kilometre of post-salt rock and the last layer of salt of up to 2,000 metres thick.
Description
- The Pre-salt is a sequence of sedimentary rocks formed more than 100 million years ago in the geographic space created by the separation of the ancient Continent of Gondwana. More specifically, it was formed by the separation of the current American and African continents, a process that started about 150 million years ago. Initially, great depressions were formed between the two continents, giving rise to large lakes. Over millions of years, the rocks that would give rise to the pre-salt region's oil were deposited there. Since all the rivers on the continents that separated flew to the lower regions, large amounts of organic matter were deposited there.
- As the continents strayed, the organic materials accumulating in the new space were being covered by the waters of the Atlantic Ocean, which was then forming. That was when the layer of salt that currently reaches 2000 meters in thickness started being formed. This layer was deposited on the accumulated organic matter, holding it there for millions of years until thermochemical processes turned it into hydrocarbons (oil and gas).
- In the current Brazilian exploratory context, the possibility of the occurrence of the set of rocks with potential to generate and accumulate oil in the pre-salt layer is in the province called the pre-salt, an area measuring approximately 800 km in length and 200 km in width, off the coast between the states of Santa Catarina and EspĂrito Santo.
- The province's reserves are located 300 km from the Southeast region, which concentrates 55 percent of the Gross Domestic Product (sum of all good and service production in Brazil). The total area of the pre-salt province (149,000 square kilometers) corresponds to almost three and a half times the state of Rio de Janeiro.