Shallow water 3D in South Gabon: a new generation of hydrocarbon prospects

Abstract

Global exploration has seen a dramatic upturn in 2018, with close to 4 billion barrels of oil equivalent discovered in the first half of the year alone, and many exciting wildcat wells still to come. Although the oil price slide of 2014 changed the industry, with the focus now on commerciality and risk reduction, it is of interest that most of the new discoveries this year have been made in commercially challenging deep water. The reason for this is that our industry has been exploring shallow-water oil-prone basins since the invention of marine seismic methods in the 1950s, and they appear now to be ‘mature’ and depleted in material low-risk opportunities. Indeed the future of shallow-water exploration has been portrayed as binary: either mopping up around what we know or exploring new frontiers. However, in South Gabon we challenge the established idea that after 50 years of exploration the basin is mature, by revealing a new generation of prospectivity with modern 3D acquisition and processing (Figures 1 and 2). The play primarily chased so far has been the Gamba Sandstone play, the seismic imaging of which has always been a significant challenge, owing to the complex velocities in the post-salt geology, the heterogeneity and the halokinesis of the Ezanga Salt. Yet with the exception of the Muruba-2 discovery, few wells have deliberately targeted the syn-rift section below the Gamba, leaving the pre-salt section completely unexplored (Figure 1). Diligent planning and acquisition (Esestime et al., 2017, 2018) of 3D data in South Gabon covering an area eight times the size of Greater London (11,500 Km2), has enabled an imaging veil to be lifted. The intra-syn-rift is now visible and is revealing large-scale hydrocarbon prospects, capable of attracting interest from global exploration players (Figure 3).