Aminex: NT-3 Targets More Than 200 Metres of Gross Reservoir at Ntorya 

From 51 Metres at NT-2 to More Than 200 Metres at NT-3

The comparison shown by Aminex is striking.

On the AGM seismic section, the gross thickness associated with the NT-2 location is marked at approximately 51 metres. Towards the NT-C/NT-3 location, the section shows gross thickness reaching approximately 210 metres, consistent with Aminex's statement that NT-C is expected to encounter more than 200 metres of gross reservoir thickness. Aminex PLC

That is roughly four times the gross thickness shown at NT-2 on this particular seismic section.

It is important, however, to understand what that does and does not mean. Gross reservoir thickness is not the same as net gas pay. A 200-metre interval does not mean 200 metres of commercially productive gas-bearing sandstone. Reservoir quality, net-to-gross ratio, porosity, permeability, gas saturation and connectivity all have to be established by drilling and logging.

What the seismic does tell us is that NT-3 is targeting a substantially thicker part of the mapped geological system than that encountered at NT-2.

That becomes particularly interesting when set against NT-2's history. The well flowed gas at an average 17 MMscf/d during its 2017 testing programme, despite now being described by Aminex as having been drilled towards the edge of the mapped channel. Aminex PLC

There is no legitimate basis for multiplying NT-2's flow rate by the difference in gross thickness and forecasting an NT-3 flow rate. Reservoirs do not work that simply. But it does provide important geological context for why APT regards the new central location as attractive.

Why NT-3 Jumped Ahead of CH-1

The change in drilling priority created considerable discussion when it was first announced in September.

CH-1 had long formed part of the initial Ntorya development programme. NT-Central, by contrast, was a well originally intended for a later development phase. Aminex's AGM presentation now confirms that the operator considers the NT-3 location to have lower geological risk than CH-1, while NT-East and NT-West may also be drilled ahead of CH-1 depending upon the NT-3 result. Aminex PLC

The new seismic information helps explain that decision.

NT-3 is targeting the former NT-8 location within the central part of the field. The updated reservoir-thickness mapping places it within one of the strongest areas of the mapped channel system, while APT's new segmentation work identifies the central segment as containing the greatest gas-in-place potential of the principal appraisal areas. Aminex PLC

Seen in that context, bringing NT-3 forward is not simply another alteration to the timetable. It appears to be a deliberate decision to put the next new well into a location offering a combination of greater mapped reservoir thickness, central positioning and lower assessed geological risk.

The Possibility of More Than Two Lithostratigraphic Units

The second statement on the seismic slide may ultimately prove just as interesting.

Aminex says the seismic interpretation and amplitude analysis indicate the possibility of encountering more than two different lithostratigraphic units at NT-3. Aminex PLC

In straightforward terms, lithostratigraphic units are separate packages of rock distinguished by their geological characteristics.Encountering more than two lithostratigraphic units could therefore reveal a more complex vertical reservoir system than is currently demonstrated by the existing wells.

That does not mean Aminex has announced multiple additional gas reservoirs. Nor does it establish that any additional units will contain commercial gas.

Those questions require the well.

But if NT-3 were to encounter several reservoir-quality intervals containing hydrocarbons, the significance would extend beyond simply proving another location within the existing field model. It could provide additional information about the vertical as well as lateral distribution of reservoir within the Ntorya system.

For that reason, the safest way to regard the additional lithostratigraphic potential is as geological upside which is not yet required for the current development case.

The Multi-Zone Idea Has Historical Roots

Interestingly, the possibility of multiple reservoir intervals at Ntorya is not entirely new.

Following the NT-2 discovery in 2017, Aminex reported that NT-2 had encountered the equivalent reservoir section around 74 metres higher than NT-1 and that traces of oil had also been observed within the gross reservoir interval. At the time, the company was using those results to update its basin model and optimise future drilling. Aminex PLC

The same 2016 Annual Report described the then-planned NT-3 well as having multi-zone potential and said its design would seek to intersect multiple stratigraphic units potentially containing hydrocarbons. Aminex PLC

That historic NT-3 was not the same location as today's NT-3, which is the former NT-8 site. The comparison therefore should not be taken as evidence that today's well will encounter those same intervals.

It does, however, demonstrate that multiple stratigraphic units have been part of the geological thinking around Ntorya for many years. The much richer 3D seismic dataset now allows APT to target those geological possibilities with considerably greater precision than was available when the earlier wells were planned.

What NT-3 Could Tell Us About the Field

NT-3 therefore has several jobs to do simultaneously.

At the simplest level, it is an appraisal/development well intended to add another successful well to the Ntorya development.

But its location means it should also test the current interpretation of the central segment, where APT's 2026 deterministic model assigns the greatest gas-in-place potential. The result should provide real well data from an area that until now has been defined principally through seismic extrapolation from NT-1 and NT-2. Aminex PLC

It will also test whether the substantially greater gross reservoir thickness suggested by the seismic is actually present at the well location.

And finally, it may tell us whether the indication of more than two lithostratigraphic units translates into additional reservoir intervals.

A successful result on all three fronts would provide much more information than simply confirming gas at another point on the map.

Conversely, the well will also give APT hard geological information with which to refine its model if the actual subsurface differs from the seismic interpretation. That is precisely what appraisal drilling is intended to do.

NT-East and NT-West Could Then Become More Important

This also places the proposed NT-East and NT-West wells in a clearer context.

Aminex has confirmed that both are conditional upon the NT-3 result. APT's 2026 reservoir-thickness map positions NT-West and NT-East on different parts of the broader mapped system, with NT-Central between them. Aminex PLC

NT-3 therefore potentially becomes the calibration point for what follows.

If the central well validates the seismic interpretation, the case for testing the western and eastern segments should become materially better informed. APT would then be moving from two historic wells concentrated towards one end of the structure to a sequence capable of providing direct geological information across much more of the field.

That is one reason the revised programme deserves to be seen as more than a simple reshuffling of drilling dates.

December Is About More Than First Gas

December already carries enormous significance for Aminex because NT-2 is targeted to deliver first gas.

But it may now contain a second event of comparable longer-term importance.

The AGM presentation says the NT-3 rig contract is expected to be signed in October, with mobilisation ahead of the planned December 2026 spud. Land rights for the wellsite and access roads have already been secured and civil works have commenced. Aminex PLC

First gas from NT-2 would mark the beginning of Ntorya's commercial production.

NT-3, by contrast, begins answering the next set of questions: how thick is the reservoir in the central channel, how closely does the new 3D interpretation match the geology encountered by the drill bit, and are there additional reservoir units beyond those already forming the base case?

Those answers could influence not only the next wells but the eventual scale and confidence attached to the wider Ntorya development.

Conclusion

The decision to bring NT-3 forward is becoming easier to understand as Aminex releases more of the geological work behind it.

NT-2, which successfully tested at 17 MMscf/d, is now shown towards the edge of the mapped channel and at approximately 51 metres gross thickness on the new seismic section. NT-3 is targeting the central system where gross reservoir thickness is expected to exceed 200 metres, while seismic and amplitude analysis suggest the possibility of more than two lithostratigraphic units. Aminex PLC

None of that guarantees the result of the well. Only drilling can establish what is actually present.

But it does explain why a target once reserved for a later development phase has suddenly become one of the most important wells in the immediate Ntorya programme.

For investors, December is no longer simply about getting first gas into the pipeline. It is also when the drill begins testing whether the strongest-looking part of Ntorya's new 3D geological model is borne out underground.

Sources

Contributing Author: Andrew Eldridge

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