São Tomé Exclusive Economic Zone

ERHC has a 100 percent working interest in Blocks 4 and 11 of the São Tomé and Príncipe Exclusive Economic Zone (EEZ) free of signature bonuses.

The close proximity of São Tomé and Príncipe’s offshore waters to the proven hydrocarbon systems in the adjacent territorial waters of Gabon, Cameroon, Equatorial Guinea and Nigeria suggests the potential for hydrocarbons, which is further supported by seismic data and petroleum seeps seen on the island of São Tomé. Seismic data for EEZ Blocks 4 and 11 contain highly prospective structures.

ERHC believes the EEZ has all the necessary components of a successful petroleum system. The region is at present unlicensed and undrilled, providing an excellent frontier exploration opportunity. See our EEZ photo album.


ERHC’s involvement in the São Tomé and Príncipe oil and gas industry stretches back to 1997 when the Company was initially granted an oil and gas exploration concession. In 2001, São Tomé and Príncipe awarded ERHC preferential rights in the EEZ. Prior to the opening of the EEZ’s 1st Licensing Round in early 2010, ERHC exercised its rights and the National Petroleum Agency of São Tomé & Príncipe (ANP-STP) on behalf of the Government of São Tomé and Principe confirmed the Block awards.

ERHC’s technical personnel selected EEZ Blocks 4 and 11 after examining good quality 2D and 3D seismic data acquired by Petroleum Geo-Services (PGS), which is assisting ANP-STP in promoting the area. The Blocks are situated to the west of the highly prospective Gabon Salt Basin.
The Area

The islands of São Tomé and Príncipe are located in the eastern Gulf of Guinea approximately 200 km south of Nigeria and directly west of the territorial waters of Equatorial Guinea and Gabon. They compose part of a north-east south-west trending chain of islands in the Eastern Gulf of Guinea

extending offshore from Cameroon. The extensive adjacent deepwater areas of the EEZ are prospective and are undrilled.

The map at right is EEZ Block 4, which totals 5,808 square km, situated directly east of the island of Príncipe. The northeastern area near EEZ Block 4 contains a large graben structure, which is bound by the Kribi Fracture Zone. Click on the map to zoom in.

The lower map is EEZ Block 11. It totals 8,941 square km, situated directly east of the island of São Tomé and abuts the territorial waters of Gabon. The Southern area, where EEZ Block 11 is situated, contains parts of the Ascension and Fang Fracture Zones.Click on the map to zoom in.

The maritime boundaries of São Tomé and Príncipe encompass an area of approximately 160,000 square km. The São Tomé and Príncipe EEZ is a frontier region that sits south of the Niger Delta, and west of the Gabon Salt Basin, retaining similarities with each.

Interpretation of 2D seismic data from the deepwater EEZ area of Sâo Tomé and Príncipe has led to a regional understanding of the subsurface geology, trapping styles and prospectivity within the region of investigation. Additionally, oil sampling of seeps observed on the island of São Tomé has suggested the occurrence of a Late Cretaceous petroleum system.

In July 2014, ERHC and the National Petroleum Agency of São Tomé and Príncipe (ANP-STP) announced the conclusion of final terms for the Production Sharing Contract for EEZ Block 11. The PSC contains three exploration phases spread over an eight-year period. The work program in the first 4-year phase commits ERHC to purchase and re-process existing data and then carry out an aeromagnetic survey over the Block. ERHC is also committed to acquiring 2,500 kms of 2D seismic data during the first phase. If, after the completion of Phase 1, ERHC chooses to continue its exploration work program, Phases 2 and 3 will last two years each with a well commitment during each phase. The PSC for EEZ Block 11 will become effective following the receipt of certain legislative and administrative approvals and the official Portuguese translation of the PSC.

In addition to the two Blocks already awarded, ERHC has rights to acquire up to a 15 percent paid working interest in two additional blocks of its choice in the EEZ. The ANP-STP has informed the Company that selection of these other blocks will take place at a later date to be determined.

ERHC will be responsible for its proportionate share of exploration and exploitation costs in the EEZ blocks.
More about ERHC Energy's operations:
Republic of Kenya. ERHC has a Production Sharing Contract (PSC) with the Government of the Republic of Kenya on Block 11A in northwestern Kenya. The Block is in the vicinity of Block 10BB in which significant oil discoveries have recently been announced. East Africa has emerged in recent years as one of the most exciting, new oil provinces in the world with the discovery of over 1 billion barrels of recoverable oil in Uganda’s Block 1 (EA1), the Ngamia-1 oil discovery in Kenya, which is estimated to be bigger than the Ugandan discovery, and large gas discoveries, including the recent Zafarani find, offshore Tanzania. For more on ERHC's operations in Kenya, click here.
Republic of Chad. ERHC has interests in Block BDS 2008 in the Republic of Chad. The government of Chad formally awarded the company the oil block for exploration and development in June 2011. A Production Sharing Contract was signed in July 2011. Chad is one of sub-Saharan Africa’s significant crude oil producers with proven oil reserves of 1.5 billion barrels. It share borders with Nigeria, Cameroun and Sudan, which all produce oil as well. For more on ERHC's operations in Chad, click here.
The Joint Development Zone (JDZ).ERHC has interests in six of the nine Blocks in the Joint Development Zone (JDZ), a 34,548 sq km area approximately 200 km off the coastline of Nigeria and São Tomé & Principe that is adjacent to several large petroleum discovery areas. For more on ERHC's operations in the JDZ, click here.