Could there be gas-charged reservoir in MOU-5?30 Apr 2025 08:46
Some people like to present technical opinions as if they were facts, and in doing so end up sounding rather like a PR person for the competition, rather than an actual geoscientist. I was taught to be cautious when expressing an opinion that other people might rely upon, and make sure that it is supported by verifiable factual data.
In order to opine as to whether MOU-5 intersected a viable gas-charged reservoir, we need to consider a number of issues.
1). Is there likely to be a gas-charged reservoir, based on what is already known?
*RNS 12 May 2022 “The potential for good quality reservoir [in MOU-5] is increased due to its structurally elevated position relative to TRF-1". TRF-1 was drilled by C-P looking for oil, but found 18m of gas-charged Domerian dolomite with 8% porosity.
* The Scorpion Geosciences ITR pointed out "the presence of potential direct hydrocarbon indicators in the preserved syndepositional crest of the structure", i.e. directly above MOU-5.
* RNS 13 July 2023: "1139 to 1143 metres TVD MD, including the top of the Jurassic carbonates, 2 metres of likely gas reservoir with average porosity 19.9% (maximum 20.6%) and average gas saturation 56% (maximum 73%)".
2). Is the potential reservoir found in MOU-5 updip of the other wells' reservoirs?
* es for TAF-1, what about MOU-4? We need to do some sums.
* Google Earth Pro, shows MOU-4 at an elevation of 348m, MOU-5 is 6m lower.
* MOU-4 Jurassic intersection was thus at the equivalent of -1133m in MOU-5.
* It was expected to be intersected between 850-950m in MOU-5 and be 250m thick.
* However, a 'substantial' thickness of salt was intersected, that puts the Jurassic contact lower than expected. The key is how much lower? This useful table of seismic conduction velocities allows us to do some calculations: https://gpg.geosci.xyz/content/physical_properties/tables/seismic_velocity.html
* Assume the salt mid-range of 5000m/s, and a 15% porosity limestone/dolomite of 4500m/s (the higher the porosity, the slower the conduction velocity).
* For every 100m of salt encountered, the expected limestone contact will be 5000/4500 + 100 = 111m lower than expected.
* I do not know what depth of salt Paul means by 'substantial', but even if it is 150m thick, that gives us a worst case (the 950m depth above) of 150 x 1.11 = 166.5m + 900m = 1066m depth, which still gives us 1133 – 1066 = 67m of reservoir updip (above) the gas charged reservoir found in MOU-4.
That 67m is pretty much what was found in MOU-5, so if the above assumptions are reasonable, MOU-5 Domerian carbonates should be gas-charged. This is of course still only my opinion, but at least I have shown my assumptions.