The Alen gas monetisation project, located offshore Equatorial Guinea, produced the first gas in February 2021.

Noble Energy, which was acquired by Chevron in October 2020, is the operator of the Alen natural gas development project. It holds a 51% operated working interest and a 45% revenue interest in the gas field, which spreads across Block O and Block I in the maritime waters of Equatorial Guinea.

The development partners in Block O are Noble Energy (45%), Glencore Exploration (25%), and Equatorial Guinea state-owned oil and gas firm GEPetrol (30%), while the partners in Block I include Noble Energy (38%), Glencore Exploration (23.75%), Atlas Petroleum International (27.55%), GEPetrol (5%), and Gunvor Resources (5.7%).

The Alen gas field development partners, the Government of Equatorial Guinea, and the owners of the Alba gas plant, and the Equatorial Guinean (EG) LNG facility entered into definitive agreements to process the gas produced by the Alen field in April 2019.

The final investment decision on the Alen gas monetisation project was reached in April 2019. The total capital expenditure in the project is estimated to be approximately £253mn ($330mn).

The gas produced by the Alen field is processed by the existing infrastructure located at Punta Europa in Bioko Island, Equatorial Guinea.

Location and reserves

The Alen gas and condensate field is mainly located in Block O and has an extension in Block I. The field is situated in the Douala Basin, Gulf of Guinea, Equatorial Guinea.

The total recoverable resources in the field are estimated to be approximately 600 billion cubic feet (bcf) of natural gas equivalent.

Alen gas field development

The project involves the Alen gas production platform connected to the existing three production wells. The gas stream from the Alen platform is transported through a new pipeline connecting the onshore facilities in Punta Europa.

The new gas pipeline is approximately 70km-long, 24in-diameter, and has a capacity to deliver approximately 950 million cubic feet (mcf) of natural gas equivalent a day.

The Alen gas stream is supplied to the Alba liquefied petroleum gas (LPG) processing plant (Alba Plant) and the EG LNG facility located in Punta Europa. The gas field is initially expected to produce between 200 and 300mcf of natural gas equivalent a day.

Although the Alen field originally started operations in 2013 with the production of condensate, the separated natural gas was reinjected to maintain reservoir pressure. The condensate produced by the field is supplied to the Aseng floating production, storage, and offloading (FPSO) vessel.

The Alen gas monetisation project acts as a backfill gas supply source to the Alba Plant and the EG LNG due to the fall in gas production at the Marathon Oil-operated Alba field. Earlier, the Alba field was the only source of feed-gas for these facilities.

EG LNG and Alba Plant

Marathon Oil is the operator of both the EG LNG facility and the Alba gas plant. EG LNG is a single train natural gas liquefaction facility that started operations in May 2007, and it has a capacity to produce 3.7 million tonnes per annum (Mtpa) of LNG. Marathon Oil holds a 60% interest in EG LNG, while the other shareholders are Equatorial Guinea state-owned Sonagas, Mitsui & Co., and Marubeni Gas Development UK.

The stakeholders of the Alba Plant include Marathon Oil (52%), Noble Energy (28%), and Sonagas (20%). The various products produced by the Alba gas processing facility include condensed gas, butane, and propane. The gas plant has undergone modifications to handle gas from the Alen field.

The Government of Equatorial Guinea plans to make Punta Europa a Gas Mega Hub providing the gas processing and liquefaction infrastructure for the gas fields of Equatorial Guinea, as well as neighboring countries. The Alen gas monetisation backfill project is considered to be the first phase of this Gas Mega Hub plan.

Contractors involved

Tenaris was contracted to manufacture the offshore pipeline for the Alen gas monetisation project in July 2019. Tenaris’s Confab welded pipe mill, located in Brazil, manufactured the line pipe.

Saipem was awarded a contract worth approximately $90-100m (£70-78m) for trunk lines and installation (T&I) works for an approximately 70km-long gas pipeline from the Alen platform to Punta Europa in November 2019. Saipem’s pipe-laying vessel Castorone was deployed to carry out the pipeline installation.

Nortrans Offshore was awarded a flotel accommodation charter contract for hook-up and commissioning work at the Alan gas field in May 2020. Nortrans-managed accommodation support vessel Temis was deployed at the Alan gas field for executing this work.