TotalEnergies is drilling Grenadier-1, on block 20/11 in the Kwanza basin offshore Angola. The Valaris DS-12 drillship is carrying out the work for TotalEnergies and partner Sonangol in 1500 m water.
Given the proximity of the Grenadier-1 location to the Golfinho discovery (10 km), it is likely that the current well is targeting a similar pre-salt carbonate structure. These carbonate bodies lie within the late rift section in the Apto-Barremian and have developed over basement highs forming a ‘string of pearls’ fairway along the basement ridges. TotalEnergies signed a sale and purchase agreement in 2019 for the block, where multiple discoveries have been made previously.
Blocks 20 and 21 have a long history of exploration in the Kwanza Basin. In the late ‘90s, it was one of the first deepwater salt basins to be tackled after phenomenal success was achieved drilling similar targets offshore Brazil such as Tupi. With great results to the north in post-salt successions in the Lower Congo basin – for example Girassol – BHP at the time acquired large 3D datasets to image the pre-salt, attempting to tie the previously conjugate South American Santos and Campos basins in terms of both geology and oil potential.
See also:
Overcoming Pre-Salt imaging challenges in the Kwanza Basin by leveraging high-end technologies to enhance imaging of existing seismic data.
BHP and ExxonMobil drilled two dry wells in Block 22 in 2001 and 2002, after which exploration activity receded until 2013. Between 2014 and 2016 the US firm Cobalt drilled 7 exploration wells over Blocks 20 and 21, with mixed results, but invariably with oil, gas or condensate pay being recorded. Cameia, Loengo, Mupa, Orca, Golfinho, Zalaphus and Bicuar all describe an arc of non-commercial discoveries from north to south. Larger companies such as bp (Golfinho), Repsol (Cameia) and Chevron (Zalophus) participated in appraising some of the discoveries, but at the time the fields were classified as sub-commercial, especially given the oil price crash in late 2014.
Given the commercial challenges, along with the depth of the target, the challenging seismic imaging issues pre-salt, and the mixed results in terms of reservoir quality and hydrocarbon phase, Cobalt were eventually unsuccessful in commercially developing this trend of discoveries.
TotalEnergies entered the blocks in 2019, allied to important lease extensions in their production heartland of Blocks 15 and 17 to the north. At a time when Angola and the ANPG are working hard to attract further investment in augmenting production and therefore exports, Grenadier may breathe life into this fascinating play, thereby potentially extending Angola’s run as a major deepwater oil producer in sub-Saharan Africa.
