Choco Pacific

Commentary

Colombia's country view is Uncertain, but the direction of policy has turned: Abelardo de la Espriella won the June 2026 run-off, took office on 7 August and in late September announced that exploration and the signing of new hydrocarbon contracts, including for fracking, would fully resume, although the announcement does not in itself change the legal framework. For this basin the policy upside is offset by acute insecurity, with the ELN and the Clan del Golfo fighting over the San Juan sub-region and displacing more than 1,300 people in August 2026, and by the low thermal maturity found in past wells. Panamá, to the north, carries no sanctions or conflict risk. Outlook: Uncertain.

Updated

October 8, 2026

Location

Description

The Choco Pacific Basin (USGS Province 6087) lies on Colombia's Pacific margin and broadly corresponds to the ANH's Chocó Basin, with the offshore Chocó Basin to the west. It is a Cenozoic basin interpreted as the product of extension in a forearc setting within the Panamá–Chocó Arc, occupying the depression between the Western Cordillera and the Serranía de Baudó. The ANH bounds the onshore basin by the border with Panamá to the north-north-east, the Garrapatas fault zone to the south and the present coastline to the west, with the offshore basin extending to the trench of the active subduction zone. The Istmina–Condoto structural high divides it into the Atrato sub-basin to the north (c. 25,000 km²) and the San Juan sub-basin to the south (c. 10,500 km²), together extending for more than 280 km. The fill, of marine to continental Cenozoic sediments on Cretaceous igneous–sedimentary basement, reaches about 10 km in the Atrato and possibly 9 km of mainly clastic rocks, deposited since the Paleocene, in the San Juan. Eocene–Miocene shales range from immature to the early oil window (Ro 0.23–0.61%), and the main potential traps are post-Miocene structures.

Summary

A lightly explored frontier with no commercial production and no USGS-assessed resources. Wells drilled by Ecopetrol in 1980–85 and by the ANH in 2011–13, including Buchadó-1, Urodó-1, Necora-1 and the ANH-Chocó ST-P stratigraphic well, found generally low thermal maturity, but the ANH estimated about 850 MMBOE of undiscovered resources in the Atrato sub-basin for its 2010 round, and about 600 MMBOE has been suggested for the San Juan. The basin lies in one of Colombia's most conflict-affected regions: after a magnitude 7.4 earthquake centred on San José del Palmar on 10 August 2026, fighting between the ELN and the Clan del Golfo in the San Juan sub-region displaced more than 1,300 people.