Shell, Texaco and Occidental, Pioneers in the Exploration of the Putumayo-Oriente-and Marañón Basins, Colombia-Ecuador and Peru

Abstract

Abstract

The Putumayo-Oriente and Marañón Basins in Colombia, Ecuador and Peru are located in a foreland zone between the Andes to the west and the Guyana shield on the east. It covers about 320,000 sq. kilometers.

Over 3 Billion barrels of oil (BBO) and 1,000 billion cubic feet of gas (BCFG) have been produced from the Putumayo-Oriente and Marañón Basins. Estimated undiscovered recoverable resources range from 1,000 to 7,000 BBO and 250 to to 5,000 BCFG. The main hydrocarbon reservoirs in the Putumayo Basin in Colombia are the Cretaceous Caballos and Villeta and the Tertiary Pepino Formations. Oil is produced in the Oriente Basin of Ecuador mostly from sandstones of the Cretaceous Hollin and Napo Formations. In Peru's Maranon Basin, the reservoirs are sandstones of the Cretaceous Cushabatay, Agua Caliente, Chonta and Vivian Formations.

Oil exploration in the The Putumayo-Oriente and Marañón Basins started in 1921. The fist discovery is Orito, in 1963, in the Putumayo by Texaco. The Oriente Basin have been intensively explored since the early 1930s. Shell first explored for oil in the Oriente Basin of Ecuador in the 40's mainly using field geology. As a result of these efforts, three wells were drilled, Macuma, Pumbuiza and Tiputini, all three abandoned with only oil shows.

Following the string of discoveries in the Putumayo Basin by Texaco in the 1960's, and interpreting the petroleum geology to continue down to the south into Ecuador and after negotiating with the government of Ecuador in the early 1960's for exploration acreage, Texaco undertook a large field geology campaign in the Oriente Basin of Ecuador, followed by 2D seismic. In April 1967, Texaco drilled the first exploration well, Lago Agrio # 1, a subtle structure in the foreland basin. The well TD into the top of the Pre-Cretaceous Chapiza Formation. The well tested 1,399 Bopd, 29.30 API from the Cretaceous Hollin Formation. This was the start of the modern oil industry in Ecuador.

The Oriente basin of Ecuador contains the largest discovery to date in the Putumayo-Oriente-Maranon basins, the Shushufindi field, discovered by Texaco in 1970, with an estimated 3.5 BBO in place.

The Marañón Basin of Peru was first explored for oil in the 1930s and 1950s. The first commercial discoveries in the basin were made by Occidental and PetroPeru in 1972.

AAPG Datapages/Search and Discovery Article #90260 © 2016 AAPG/SEG International Conference & Exhibition, Cancun, Mexico, September 6-9, 2016