1.) The Mud Logs are absolutely abysmal in quality. For a project of this Calibre and excitement the work performed is absolutely pitiful. (And that is putting the best spin possible on what is presented.)
2.) The scales on which the company has presented the petrophysical analysis is horrible. Probably deliberately done so as to make any evaluation highly challenging?!
3.) In spite of the terrible mud log quality and the lack of any professionalism in interpretation and quality - the fact that the C1 curve is presented makes it possible to correlate with features seen on the petrophysical and FMI (Formation Micro Imager) log plots. The best resolution I can get off the petrophysical plots is about 0.5m sort of details. (With effort I might get down to about a 0.25m level of precision? (But for an exploration well drilled in a new sedimentary basin - 0.5m level of precision is fine enough!!)
4.) The sand stacks down to the bottom of the sections displayed are silty and muddy in many parts and only the best and cleanest should be evaluated - and only where they occur under a good overlying claystone seal. (In other words - the best of the best sands are what matter - the rest are academic if these best sands do not form hydrocarbon bearing reservoirs!)
5.) The stratigraphic section below 1250m shown in the presentation is mostly complexly interbedded thin anhydrites, marls, dense tight limestones and calcareous dolomites. There is evidence from the FMI logs of common bituminous algal mat dead oil residues associated with the Anhydrite/dolomite rhythmites. Most of the section displayed is absolute tombstone with about 6.0m Gross earthy dolomite porosity in the zone of interest developed between 1336m and 1362m measured depth. This gross thickness is generous as I rounded all intervals up to the nearest 0.5m thickness. The interesting (?) dolomite porosity is divided into six thin discrete intervals.
6.) The sand porosity intervals have up to 15m Gross clean sand porosity in three separate intervals of interest. Each has from 21-29% clean sand porosity and a 98.0% to 99.7% estimated water saturation. (Basically soaking wet and 100% water saturation!)
7.) The only Carbonate zone of interest around 1350m shows a couple of possible fault related fracture porosity zones with 15-17% porosity and 65% water saturation values and other thin dolomite porosity zones with around 8-13% porosity and water saturations in the 45-65% range. (There are bound to be stylolitic and stromatolitic - algal mat - associated bitumen laminae mixed in with these sediments due to the environment of deposition - and it is this residual algal bituminous matter that is showing up as "residual oil" in the (academic to earthy) porosity. In this kind of dolomite - such porosity is essentially "tight" and completely ineffective. (The Midale Marly for example typically has to have some 28-35% porosity - and huge oil saturation - to be considered economic.)
8.) Looking at the intervals presented = and taking advantage of the previously published material - there is absolutely nothing here of any economic - or even potentially economic - interest.
The zones of best interest:
Clastic section. (Sands)
906-910m 4m Gross clean sand with 21-25% porosity, 1.5 ohm.metre formation resistivity and about 99.7% water saturation.
990-997m 7m gross clean sand porosity with 25-27% porosity, 2.8 ohm.metre formation resistivity and a calculated 98.0% water saturation.
1000-1004m 4m clean sand porosity under a nice claystone or shale seal. 26-29% porosity with 2.0 ohm.metre formation resistivity and a calculated 98.0% water saturation.
Basically anything over a 90% calculated water saturation is really something that is 100% water. (The detailed numbers here are just academic - there is no hydrocarbon gas or live oil present in any of these sands.) This inert nature of these sands is confirmed by the mud logs and gas chromatograph values recorded and presented both here and elsewhere.
The Carbonate/evaporite section (Below 1250m)
1338.0-1339.0m 1m earthy dolomite with 9-10% porosity, 30 ohm.metre formation resistivity, and 0.2-4.0 Units maximum mud gas. The FMI indicates "resistive fractures" here - I suspect merely algal mat bitumen laminae?
1340.5-1341.0m 0.5m dolomite earthy porosity from 9-10% with a 10 ohm.metre formation resistivity value. No useful mud gas. (<0.2 Units) FMI log shows trace fault here?
1341.5-1342.5m <1m of a potentially fractured dolomite to dolomitic limestone with 15% porosity and 10 ohm.metre formation resistivity values.
1348.0-1348.5m ~ 0.5m of fractured dolomitic limestone with 15-17% porosity and 20-25 ohm.metre formation resistivity values. The FMI log picks this out as a probable fault intersection? There is no response on the mud gas log with the chromatograph again showing <0.2 units of mud gas.
1350.5-1351.5m earthy dolomite porosity between 12-13% with 10 ohm.metre formation resistivity values. Mud gas values go from <0.2 units, up to 2 units, and then back down to 1.0 units of gas. The FMI log indicates the presence of "resistive fractures" - again probably stylolitic to stromatolitic algal bitumen laminae. This unit sits below a dense 2.0m thick limestone bed and above a 2.5m thick clay rich marl.
1354.0-1356.0m here is the thickest dolomite porosity zone with porosity increasing from 9% at the top, through 11% porosity in the best zone in the middle, down to 8% porosity at the base. The FMI logs confirm algal mat stromatolites at the top and base. Mud gas values increase from 1 unit above through 2 units in the middle and base.
1356.5-1357.5m 1m tight dolomite with 1-2% porosity and 100-200 ohm.metre resistivity values. Effectively "tombstone." Mud gas goes from 2 units to a peak of 5 units here before dropping back to < 1 unit.
1359.5-1360.5m 1m of dense low porosity earthy dolomite. 2-4% porosity with 100-200 ohm.metre formation resistivity values. FMI log shows "resistive fractures" once again - algal bitumen laminae as before. Mud gas drops from 2 units to back to <0.2 units once again.
From the report the average value of water saturation across this zone is about 56%. Eyeballing the petrophysical chart presentation the values range from 45-65% in value. Interpreting much of the residual "oil" showing in the porosity in this gross interval as being composed of algal mat bituminous laminae and stylolitic bitumen residues would therefore bring the effective water saturations in here back up to around 90-100% and render much of the inferred porosity as being almost entirely ineffective?
The gross interval itself is laminated or thinly bedded, cyclically bedded with limestone, dolomite, anhydrite and marl interbeds. The inferred algal mat bitumen (confirmed for me on the FMI image logs) are exactly what would be expected in the sedimentary environments represented by such a sedimentary sequence here. There is also the possible contamination with wind blown desert silts and ultra fine sand grains which make the petrographic evaluation somewhat vague in parts.
Basically taking this section at its face value - it has absolutely nil chance of providing any useful reservoir material. The only way this could become reservoir material is if somewhere laterally this kind of sequence changes into something that is a dolomitised lime grainstone or packestone fabric with considerably increased porosity (25-35%) and a much thicker sedimentary package. (Greater than 3-4m thick in any individual zone?)
There is nothing here for anyone to get excited about... Nothing at all.
The only possible hope for Reconnaissance of having a play here in this sedimentary basin is to hope that somewhere those shallow sands form a complete 4-way closed structure - and that they are hydrocarbon charged!
There is a slim possibility of such happening - but I suspect that the break between the overlying clastics and the underlying carbonates and evaporites that happens at around 1100m measured depth represents a major unconformity. Any oil or gas generated in the underlying evaporites and algal material will have escaped to surface before the overlying much younger sands and clays were deposited over the region.
If that is the case they can drill a thousand holes in the ground here and they will find nothing more than what they already have. Tight carbonates and evaporites with nil reservoir development potential and highly porous sand and clay units with nothing to charge any potential 4-way closures and traps.
Sad but this is the most probable outcome here.