Efficient Drill Bits for the Pre-salt
The expression "pre-salt" refers to an aggregation of rocks located offshore along large portions of the Brazilian and West African coasts, it forms a carbonate rock interval that ranges under an extensive layer of salt which, in certain areas of the Brazilian coast, can be as much as 2,000 meters thick. The total depth of these rocks formations, or the distance between the surface of the sea and the oil reservoirs under the salt layer, can be as much as 7,000 meters. Drilling in the pre-salt is extremely complex and may require multiple trips being made by the drill bit in order to drill short lengths due to different rock layers with varying degrees of hardness. Another challenge is that the salt is very corrosive and is also plastic, as you drill down, it tends to close the well walls.