GEO ExPro

Liberia: Undrilled Harper Basin

Liberia progresses with 2020 licensing round, offering nine offshore blocks for oil and gas exploration in the underexplored, yet prospective, Harper Basin.
This article appeared in Vol. 17, No. 3 - 2020

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Liberia: Undrilled Harper Basin

Unlike many countries, Liberia has decided to continue with its planned 2020 Licensing Round, which was launched in April – fully embracing the current situation by using a webinar as the launch vehicle and conducting a number of online interviews and participating in further webinars and virtual meetings.

  • Map showing location of acreage on offer in the Harper Basin, plus available TGS 3D and 2D seismic data. © TGS.

The round offers nine blocks, each up to 3,500m2, covering all of the offshore Harper Basin, which is situated in the south-eastern part of the country and is one of the only remaining undrilled and essentially unexplored areas of the West African Transform Margin. Water depths range from less than 200m to over 3,500m. Over 17 wells have been drilled offshore Liberia, all in the Liberia Basin to the north-west of the Harper Basin, and although no commercial discoveries were made, several sub-commercial discoveries prove that there are working petroleum systems offshore Liberia.

Nearly 6,000 line-km of 2D and 6,167 km2 of 3D seismic data cover the blocks on offer, together with marine gravity and magnetic data. TGS, which is working with the Liberian authorities on the licensing round, believes that this data reveals significant subsurface prospectivity that suggests that the Harper Basin has a petroleum system analogous to those of surrounding basins associated with the recent discoveries in Ghana, Côte d’Ivoire and also the conjugate Guyana. The company has identified many leads and prospects across the entire basin. 

The geological history of the region is closely related to the opening of the Atlantic Ocean. Sources are thought to include Albian lacustrine and Cenomanian marine shales and, in common with other basins on the West African Transform Margin, the main reservoir targets are Albian and Upper Cretaceous sandstones. Anticipated plays include tilted fault blocks; syn-rift basin floor fans; pinch-outs against growth faults; and channel systems such as turbidites and contourites.

The licensing round has been timed to coincide with positive amendments to Liberia’s Petroleum Law, including a provision for a mandatory 5% interest in all petroleum agreements to be awarded to Liberian-owned companies and the extension of the exploration period. The bid submission period starts on 1 November 2020 and the license round closes at the end of February 2021. This bid round is specifically for the Harper Basin, but there is a provision in the Law to allow for direct negotiation for blocks in the Liberian Basin.

Further Reading on Oil and Gas Exploration in Liberia

Liberia - A Fresh Approach
Ben Sayers and Alex Birch-Hawkins, TGS; Rufus Tarnue, NOCAL; Gerrard Spear, Lauren Mayhew, Lyme Bay Consulting
New thinking inspired by innovative modelling could open new plays in West Africa.
This article appeared in Vol. 14, No. 5 - 2017

Liberia: Significant Oil Discovery
Jane Whaley
Liberia’s race to join its West African neighbours Sierra Leone, Côte d’Ivoire and especially Ghana has moved an important step forward.
This article appeared in Vol. 9, No. 3 - 2012

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