I have been readinga few geological papers / articles on the Orange Basin and some takeaways are shared here. In my view they have relevance to PEL-87.
Apologies for the geo-speak. TheOrange Basin’s post-rift sedimentary sequence comprises two major depocenter's,inboard and outboard sub-basins, divided by a NW-SEtrending topographic high referred to as the outer high / marginal ridge (orange line on map below) which in my opinion, has relevance to PEL 83, 85, 87 and 39: licenses located east of the outer high / ridge. The outer high / ridgedevelopedas a regional trend during extrusion of flood basalts and apparently can bemapped from the Walvis Basin south to the Orange Basin on 2D seismic data. This outer high / ridge divides two major Orange Basin depocenter's, an outer sub-basin west of the outer high / ridge (Venus discovery) and an inner sub-basin east of the outer high/ridge, (Mopane, Saturn, Graff?). There has been some discussion on the outer high / ridge previously on hot copper.
Papers mention that the outer high / ridge played an important part in controllingreservoir and source rock distribution and deposition and was partiallyresponsible for generating various trapping configurations. Another article surmises that the outer high/ marginal ridge is a prominent structural feature all the way along theNamibia and South Africa margin and has probably played an important role inthe deposition of the Graff-1 Late Cretaceous reservoir by acting as abackstop, causing turbidite sands to pond east of the outerhigh.However, on the diagram below showing the Jonker, Graff and Mopane discovery wells,the Graff sands are shown to be deposited west of the outer high. In my view,the Graff sands are deposited on, and/ or east of the outer high, like Saturn inPEL-87 and perhaps the Mopane’s discoveries.
It isthought that the outer high also affecteddepositionof Albian turbidite fans which in some areas ponded, thinned, or pinched-outagainst this topographic feature. Lower areas or ‘gaps’ in the outer high (see first map) allowed turbidite sediments to more easily reach deepwater areas. The Venus,Jonker and Enigma follow-up discoveries are located seaward (east) of one these‘gaps’ in the outer high / marginal ridge where sediments could more easilyfunnel through to more distant slope and deepwater areas. Asdiscussed in the GEOExPro“getting close to Mopane” article, the Mopane complexappears to hold both the Late (Upper)CretaceousCenomanian – Turonian (CT) play seen at Graff and Lesedi, and the Lower (Early)Cretaceous Albian-Aptian play seen at Venus and Jonker. A major detachment atCenomanian level appears to underlie high-energy clastics, forming combinationstratigraphic/structural traps in the Cenomanian/Turonian. Neil Hodgsonmentioned that Galp describes the Aptian/Albian succession above the sourcerock as a “complex of channels”. On the Searcher seismic line below (located just east of the Mopane discovery), note the similarities with the PEL-87 seismic line (gravity-driven fold and trust belts, Cretaceous Albian-Aptian sands, Aptian source rock (Kudu Shale).
Given PEL-87’s location east ofthe outer high, as with Mopane, and PCL managements view that we have multiple play types to map out, certainly supports optimism for multiple, prospective oil targets in PEL-87, as demonstrated at Mopane.
There are too many growth / company making plays in PEL-87 for Woodside to opt out of drilling this license.
Kind regards OldGeo
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