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Dugong Exploration Well, 5 min review

Here is a 5 minute well review of the Dugong well Neptune Energy are drilling these days in the Snorre/Stafjord area, in the northern North Sea, also called the Tampen area.

This work is done in less than two hours following our standard offset review process in our platform.

Dugong

Geology

Based on information on the Neptune Energy press release, they are drilling to about 3400m TVD. They haven't specified the target formations, but we can assume Statfjord Group or Brent Group as target based on depth and offset wells. We have rich experience from drilling these reservoirs.

Draupne

There are no significant stratigraphic uncertainties in the overburden, expecting a column similar to this (above), from nearby well 33/6-2 which is a bit deeper and further west. This well also explored some sandstones in Draupne, which could be a reservoir potential for the Dugong well.

There was a kick in a nearby well 34/4-3, exiting Shetland at 3555m TVD, in a brief Cromer Knoll section. Gas kick. Maybe that is what they are drilling for now?

Geo offsets

Well Planning Issues

Doing an offset review in the area, you find this is a fearly high pressure area. Deep wells with high temperatures (up to 150C) call for some extra attention to equipment qualities.

Pressures offsets

Considering pressure issues, the upper sections have typically been drilled with WBM, and the deeper with OBM. Some wells are with 1.5 SG mud in the reservoir, which gives a rather normal reservoir pressure, while others are drilled with up to 1.97 sg mud in the reservoir. Which is high.

The reported mud weights are higher than seawater, which means there has been uncertainty about shallow hazzards. One well had an open hole pilot for the 20" section, but didn't report any incidents.

Open hole

Trajectory

The well is named S, which means there is planned some deviation drilling. I would assume this is deep, and close to the reservoir as they are able to place the wellhead where they would like. There might be some shallow hazzards, seabed issues or faults they want to avoid, but that information is not available.

Our machine learning gave us lot of matches in the trajectory similarity, so there are plenty of wellbores to learn from.

Trajectory similarity

Here is how these wells look in 3D:

Similar trajectories

As you can see, there are a multitude of wellbores to learn from, with shallow or deep kick offs. Some are also quite close to the well being drilled.

Trajectory offsets

Casing Design

The casing design in the area looks as conventional as can be, and I'm guessing Neptune are not taking any risks on slimming their well. They are probably rather focusing on their dual derrick performance.

Summary

This seems to be a straight forward well to drill, without any significant issues. If I was in charge I would push for performance, slim down the well design and strengthen the decision process to avoid the random operational mistakes our industry is so prone to.

I spent two hours on this review, and I hope you found it useful. We know how much oil companies struggle with doing offset reviews based on data, and we provide training and the platform to get up and running in a few months.

We're happy to give a demo of our product, training and data management services to anyone in the world, our customers range from the largest international oil companies to more specialized national companies.

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