Exploration & Gas Monetization in East Africa


The Rovuma Basin of Southern Tanzania and Northern Mozambique

Rovuma Basin

Oil and gas exploration in the Rovuma (also spelled Ruvuma) River Basin started almost 50 years ago but early wells were either dry or gas prone. This led to the region being largely ignored for several decades. Upstream investments remained relatively small until 2005 when Wentworth bid for and won concessions in three Rovuma Basin blocks. At that time the Company was partnered with Anadarko and the national oil company in the onshore and offshore Rovuma concessions in Mozambique and held an 80% interest in the Mnazi Bay Concession in southern Tanzania with that country's national oil company.

Work began in all three concession areas in 2006 and by 2008 new seismic had been acquired in Mnazi Bay, Tanzania and onshore and offshore Rovuma, Mozambique. One well re-entry, two appraisal wells, and one exploration well were drilled in the Mnazi Bay Concession and all four wells flowed natural gas. For a period of time following the global financial collapse in 2008 work in the area slowed but resumed in 2009 with the drilling of the Mecupa-1 well in the Onshore Rovuma concession, Mozambique. Anadarko's initiative to drill deep-water wells in the Offshore Rovuma Area 1 concession began in late 2009 and the success of those wells would go on to change perceptions of the East African margin and the Rovuma Basin's prospectivity forever.

To date Anadarko has drilled more than a dozen deep-water wells with: six significant natural gas discoveries; five appraisals of discoveries; and one well with a 125' column of oil and gas saturated sands. The oil encountered in this well is the first known occurrence of liquid hydrocarbons in deep-water offshore East Africa. To the east of the Offshore Area 1 concession ENI has drilled two major natural gas discovery wells and appraisals of those wells in the Offshore Rovuma Area 4 concession.

Anadarko's early success led to:

  • BG Group farming-in to offshore Blocks 1, 3 and 4 in Tanzania with Ophir;
  • BG Group and Ophir drilling in total nine successful natural gas discovery wells in the three offshore blocks;
  • ExxonMobil farming-in to offshore Block 2 in Tanzania with Statoil;
  • Statoil and ExxonMobil drilling three successful natural gas discovery wells in offshore Block 2;
  • Shell and PTTEP of Thailand competing to acquire Cove Energy and its 8.5% stake in Offshore Area 1, Mozambique (PTTEP won the right to acquire Cove for US$1.9 billion in August 2012);
  • CNPC (PetroChina) buying 20% of ENI's holding company that owns its stake in Offshore Area 4, Mozambique, for US$4.21 billion; and
  • ONGC Videsh and Oil India buying a 20% stake in Offshore Area 1, Mozambique, from Anadarko and Videocon for US$5.12 billion.

In addition to current and committed future drilling, emphasis by operators is shifting to how they are going to monetise what is currently estimated to be in the region of 175Tcf of gas. Liquefied Natural Gas or LNG is the logical solution but for concessionaires with smaller known or expected resources, alternative monetization solutions have to be considered. In the case of Wentworth and its Mnazi Bay and Rovuma Onshore concessions, there are multiple monetization solutions under consideration and development including:

  • Supplying up to 270mmscf/d of gas to the Mtwara to Dar es Salaam pipeline project (completion expected in the 2nd half of 2014);
  • Supplying in the region of 140mmscf/d of gas per project to Wentworth-led gas-to-petrochemicals projects (awaiting sufficient reserves certification and FID in Tanzania and Mozambique); and
  • Supplying unspecified amounts of natural gas to area LNG plants (under development) for export

In the case of gas-to-petrochemicals projects Wentworth commissioned and completed pre-feasibility and product scoping studies to look at and consider multiple monetization solutions. The results of this study point to the production of methanol and ammonia/urea as the optimal solution. Wentworth, with the support of the Tanzanian and Mozambican governments, is pursuing the development of these projects and expects a Final Investment Decision immediately after the outcome of new exploration and appraisal drilling is known.