Mamba and Coral: supergiant gas discoveries in the Rovuma Basin, offshore Mozambique

The Rovuma Basin, once overlooked for oil and gas exploration, emerged from 2020 as one of the world's most prolific hydrocarbon provinces following the discovery of approximately 200 trillion cubic feet of gas in five years. Among the most significant discoveries were the supergiant Mamba and the giant Coral fields, discovered in 2011-12 by a joint venture led by Eni. Eni was one of the few companies to initiate exploration in the Rovuma Basin in 2006, when the area was regarded as non-attractive. The Mamba and Coral prospects were initially identified in 2009 through 2D seismic and were subsequently confirmed in 2010 using 3D seismic imaging. These discoveries are in structural-stratigraphic traps supported by Direct Hydrocarbon Indicators (DHIs). Drilling revealed the presence of multiple high-permeability Paleogene sandstones gas pools, with six of these exceeding the 500-million-barrel-of-oil-equivalent threshold, classifying them as giants. Several of the Mamba field reservoirs extend into the adjacent Area 1, where exploration has been conducted by an Anadarko-led joint venture. Both fields exhibit exceptional reservoir quality, with reservoir units exceeding 100 meters in gross thickness and extremely high net-to-gross ratios (up to 80–90%). The superior reservoir quality is attributed to the synchronous interaction of turbidite gravity flows and sea-bottom currents, which redistributed finer sediments and concentrated thick, clean sandstone deposits along the system's depositional axes. The Coral project represents the first gas production from the Rovuma Basin's deepwater discoveries. Production commenced in November 2022 via the Coral Sul, a Floating Liquefied Natural Gas (FLNG) system.