Member Info for Exploration

FD

I’d have been more surprised if Deltic had NOT found gas.

After all, the previous three wells on 41/5 and 41/10 have found gas in Haup Dolomite and Platten Dolomite.

In fact, 41/10-1 was drilled nearly 30 years ago in 1994 on 3D seismic.

But all three wells failed to flow gas from tight reservoirs with about 7% porosity.

So finding the gas is easy, but getting it out may be difficult, which is why Shell pre-applied to test.

The inept announcement that the current well would be plugged and abandoned on the same day drilling started hasn’t helped the share price.

thanks `snoop - the ship is dynamically positioned about 150 metres down wind from the rig.

Eco

Drilling, coring and logging should be complete by now. TD is only 6000 ft BMSL. Previous wells on 41/5 and 41/10 have taken about 45 days to drill and test.

My interpretation is that gas has been encountered and a decision has been made to flow test the well based on cores and logs. In fact all previous wells on the licence have found gas - its just the reservoir which is the problem.

Normand Tantalus has been on station at Mearsk Resilient for the last 24 hours - longer than needed to unload equipment but perhaps to test the well which is the way NSTA prefers to see it done now-a-days.

(Tantalus is a big DP PSV which can can be used as a WTV - (well test vessel). A modular separator etc can be installed on the deck to separate water, condensate and gas. The WTV is connected to the well using a long flexible hose. Liquids are stored aboard the WTV. The gas is flared and the heat from the flare is remote from the rig for added safety. Shell/Deltic’s plan all along has been to drill the well and conduct a short-term flow test to find out if there are moveable hydrocarbons in what is known to be a very tight carbonate reservoir from the previous three wells on the licence area. Whatever the outcome the well will be plugged and abandoned while the results will be analysed to determine if more appraisal wells can be justified).

Drilling, coring and logging should be complete by now. TD is only 6000 ft BMSL

Normand Tantalus is heading for Mearsk Resilient. Tantalus is a big DP PSV which can can be used as a WTV - (well test vessel). A modular separator etc can be installed on the deck to separate water, condensate and gas. The WTV is connected to the well using a long flexible hose. Liquids are stored aboard the WTV. The gas is flared and the heat from the flare is remote from the rig for added safety. Shell/Deltic’s plan all along has been to drill the well and conduct a short-term flow test to find out if there are moveable hydrocarbons in what is known to be a very tight carbonate reservoir from the previous three wells on the licence area. Whatever the outcome the well will be plugged and abandoned while the results will be analysed to determine if more appraisal wells can be justified.

5000 feet BMSL

Ecologist

There are 3 previous wells in this licence area. 41/5-1, 41/10-1 and 41/10-2. The longest drilling time, including testing, is 45 days. After all, it’s only 5000ft BMSL to the reservoir.

So where does the 60 to 90 days come from? The recent presentation shows the current well on Pensacola is a vertical well which is designed to test whether moveable gas and condensate will flow from the primary Zechstein target. This implies all the testing permits have been granted prior to drilling. Deltic also says there will be a period of evaluation followed by appraisal drilling next year - assuming there is money to do it.

The previous wells have found gas in a tight reservoir. So one outcome here is a lot of hullabaloo followed by unconscionable ‘delays’ before anything else happens. Looks like bonuses all round and another salary boost for another 12 months!

FD

As you know all joint ventures agree an annual work programme and budget, usually in September/October each year. This is usually specified in the joint operating agreement. The process enables each company to make a budget for all its ventures and plan ahead to meet cash calls, overheads and raise more ‘equity’ (a polite word for money)

For P2252 i.e. the Pensacola well, a joint technical team all assess the scientific drilling results and recommend to the ‘Operating Committee’ - who are nominees from each company - a course of action.

The Operating Committee then decides on whether to spend the money, taking everything into account including economics, government policy, company tactics and so on.

One of the Operating Committee’s responsibilities is a agree a form of words to be released to the markets. That’s why RNS announcements always look like they’ve been written by a committee - because they have!

GS has his hands tied - there’s a limit to what he can announce.

FD

There’s no shortage of speculation here, especially after GS announced well will be ‘plugged and abandoned’ the same day drilling started - But that must have been approved by Shell according to the JOA.

My interpretation of the announcement is that Shell may have ‘pre-applied’ to conduct a drill stem test from the current exploration well. If so, the plan may be to drill a vertical well 50 metres into the Carboniferous after coring the Zechstein primary target, run logs and if there is moveable gas, conduct a short DST. An exploration well is just that, and is no use as a future producer so will be P&A as announced.

But what next? I wouldn’t mind betting there will be another announcement about “further studies and appraisal drilling next year” - in other words will Shell pour more appraisal money into the project? That depends on the well result (+ existing wells and 3D seismic)

Bonuses and salary hikes all round for Deltic management.

(- followed by another year of ‘told you so’ from Noel)

Previous wells on P2252 include 41/5-1, 41/10-1 and 41/10-2 & 2Z. All found traces of gas and a zone in Haupdolomite had promising potential. But, after testing, there was no flow from the tight Zechstein reservoirs and deeper, Carboniferous reservoirs were written off.

Nowadays, DSTs are discouraged by NSTA and require a lot of paper-work before permission is granted. The general idea is that coring and logging has advanced to get a good preview of reservoir properties.

So one question is what is Shell/Deltic doing differently today to establish commerciality? They'll be keeping that confidential for now.

There is a clue in the forecast duration of the drilling at Pensacola of 60 to 90 days. One possibility is drilling a vertical well and preserving the option to drill one or more deviated wells from the vertical well bore. Poro-perm properties in the main objective are known to be patchy and can change laterally in a few tens of metres.

Previous wells had a duration of ~45 days - including testing. Take 41/5-1 as an example - the main objective was ~Carboniferous at ~6000ft but gas was found in Zechstein around 4500ft - not deep by UKCS standards.

41/5-1. TD: 6280ft KB: 83ft WD: 274ft

Spudded: 29 September 2004
Abandoned: 13 November 2004

Rig: Stena Spey

Cores: None

DST#1: Carboniferous; 5,975-6048ft Abandoned
DST#2: Zechstein - 3 intervals perforated
4342-4446ft
4404-4446ft
4570-4603ft
4638-4663ft

Brine + mud recovered after 3 nitrogen lifts

https://www.youtube.com/watch?v=imV4L2i3X0c

Pre-loading;

Days a few days

https://www.youtube.com/watch?v=dn1J2YWDdVA

Bubble

No high pressure i.e. stable weather forecast for couple of weeks. As with petroleum operations everywhere its '20% activity' and 80% ‘hanging around’.

Regardless of current wind and sea state conditions, compliance with standards set by agencies such as DNV are required to satisfy insurers of rigs etc. Before committing to start the towing operation, a tow out criteria of Beaufort Force 5 or better for the coming 24 hours or even for the duration of whole moving operation is normally expected. Also, the bollard pull of the tugs must be sufficient to maintain a fixed position of the tow for given wind/tide strengths during the move. It’s all specified.

The sea state forecast today on Dogger Bank is moderate to rough with wave heights around 2.5 metres and up to 3 metres and wave period of about 6 seconds. The rig legs are designed to tolerate a certain amount of ‘wobble’ caused by heeling of the barge at sea before they become damaged.

Classic North Sea winter operating conditions ‘waiting on weather’.

Severe gale Force 9, gusting Storm Force 10 over next 24 hours. Outlook; moderating later in week.

Looks like rig-move preparations are underway with survey vessel Boka Polaris on station. This is a construction/DSV ship with remote control subs equipped to take photos of the sea bed footprints of the spud cans. It’s important to check the inter-action of the spud cans and the L13 mono-tower foundation supporting the riser and ‘dry tree’. This is type of mandatory ‘de-risking ‘insurers and regulators require.

86EE

Two wells drilled in P2252 in the 1990s on the licence discovered gas in the Permian Zechstein and / or Carboniferous reservoirs. However, due to technical failures, the flow test results for both wells were inconclusive. At the time the primary objective of these wells was the deeper Carboniferous reservoirs which contain gas but were ‘tight’, while the Zechstein was considered to be just a drilling hazard or “lost circulation zone” (which led to a well control incident on 41/5-1.

So it would be a huge achievement NOT to find gas in the new well although only an extended well test will prove commercial flow rates. Deltic/Shell have not revealed anything about their specific.objectives but they will be looking at the Carboniferous play too. Today’s hydraulic stimulation technology may be applicable to generate commercial flow from the Carboniferous.

See 2015 CPR and note there was a 3D seismic survey already. Wells were located on maps of the ‘BPU’ - or the Base Permian Unconformity - effectively Top of Carboniferous. One hopes the recent Shell 3D has provided more details of intra-Zechstein stratigraphy to pinpoint zones of high permeability.

https://www.rns-pdf.londonstockexchange.com/rns/7920H_-2015-12-2.pdf

Uggy

I think the heavenly twins are very keen to leave the mess they've made for Cathal to clear up. After all, let's remember they probably have early termination clauses in their Directors Contracts which compensate them with 1 or 2 years salary. Perhaps same applies to the other four directors proposed for getting the boot. Now we know what Oza is referring to when he talks about 'Net Pay' - it's not about petroleum geology, but it's actually about his salary!

Bubble

Several deep depressions arriving Dogger Bank for couple of weeks with southerly gales.

https://www.windy.com

With jack-up barges it is desirable to keep what sailors call ‘green water’ off the deck so they’ll be keeping a weather eye on the forecast. Oh yes, Shell probably pays moving costs however long it takes to get to Pensacola.

Gale Force 8/`Severe Gale Force 9 forecast over Dogger Bank for last days of October/early November

https://www.windguru.cz/327596

Maersk marine staff will have pre-determined limits on met-ocean conditions when they can move rig.

Bubble

Glad you looked at it. Suppliers have adapted over last few years to enable staged fracking to be completed in horizontal wells in matter of days rather than months, frequently from a dedicated 'fracking ship' - basically a supply boat with pumps, propant, instrumentation, etc. Also, by setting up an array of sea-bed geophones it is now possible to pinpoint the subsurface location and scale of subsurface fractures.

At Ensign, Centrica cut cost of hydraulic stimulation even more by using sea-water instead of potable water with fancy chemical additives.

The credit for these advances is result of technology transfered from onshore Germany where it is standard procedure to enhance flow from conventional Permo-Triassic sandstones - and has been for 40 years.

Link below might be interesting to you.

https://www.nstauthority.co.uk/media/4521/oga-sns-tight-gas-stimulation-december-2017.pdf

PS Hydraulic stimulation won't work at Pensacola - it's limestone!

No 1 plasterer

I've posted this before. Its a slide show on how Centrica turned the Ensign gas discovery, near Selene, into a commercial success using hydraulic stimulation.

https://cupdf.com/document/ensign-unravelling-the-enigma-devex-ensign-unravelling-the-enigma-ensign.html?page=1