Wednesday, September 12, 2012

Become An Arctic Oil Expert in Just Ten Minutes a Day

The Anchorage Daily News Tuesday reported that Shell has halted drilling on the Chukchi Sea.
Shell Alaska spokesman Curtis Smith said drilling was stopped as a precautionary measure in accordance with its ice management plan. (emphasis added)
This isn't hard, but it is complicated.  Just give me ten minutes a day scattered over the next months and you can dazzle your friends and enemies with your knowledge of Arctic oil drilling. (I'm hoping I will figure some of this out too by the end of this exercise.)  I'm going to give you info in small chunks.  If by the next big oil spill, your friends aren't amazed at your brilliance, you'll get double your money back.  No questions asked. 

Today we're going to look at some charts from the Ice Management Plan (IMP).  I know, who wants to read charts?  Trust me, it's easier this way.  I'm just asking for ten minutes.  Surely you spent (or will spend) more than ten minutes today doing something something frivolous.  Now's your chance to balance your karma.  And enhance your self-worth. 

So, what's "in accordance with its Ice Management Plan" (mentioned in the quote above) mean? 

Here's the chart explaining the alert levels for ice warnings:

[The "T' (TIME) acronyms are explained in the right column of the second chart.]

Screen Shot from Ice Management Plan p. 9

VMT Vessel Management Team. This team is headed by the Drilling Vessel Master and includes the Shell Drilling Foreman, Rig Superintendent, Drilling Vessel IA and the Chief Engineer. MT Move-off Time. The time required to clear decks on the anchor handler recover all anchors conventionally and move off the drill site in an orderly fashion.
IMV Ice management vessel. Any ice class vessel tasked with ice management duties in support of the drilling vessel. This includes the primary ice management vessel (IMV) and the ice class Anchor Handling Tug Supply (AHTS) ST Secure Time. The time required to secure the well, disconnect the Lower Marine Riser Package (LMRP) from the blowout preventer (BOP), recover and secure the riser.
SIWAC Shell Ice and Weather Advisory Center located in Anchorage. The center develops forecasts from various sources, and disseminates same. T-Time Total Time. The sum of ST + MT.
IMV Master Ice Management Vessel Master HT Hazard Time. The estimated time it will take for hazardous ice to reach the drill site.
PIC Person In Charge

IA Ice Advisor COCP Critical Operations Curtailment Plan
AHTS Anchor handling tug supply LMRP Lower Marine Riser Package

The next charts can be seen clearly if you click on them.  You can see the the originals at pages 11 and 12 of the Ice Management Plan (pdf). If you read closely, you'll see this is mainly about who has what responsibilities.  It doesn't tell us much about what they actually do to shut down the well head and secure

Click to see clearly

Click to see clearly

I had a lot of trouble figuring out what exactly they did.  I kept reading vague language  and  phrases like "Commences securing well in accordance with agreed upon plan, informs VMT of progress."  But where's the agreed upon plan?

Finally in Attachment 4, we get some detail.  Presumably these are the things that needed to be done to shut down the well.
Attachment 4 – Well suspension Options and Contingencies
In all the following well suspension scenarios, the assumption is that a determination has been made by the Shell Drilling Superintendent, the Shell Drilling Foreman, the Drilling Superintendent, the Drilling Vessel Master and the VMT that a hazard exists and the well should be suspended. The Shell Drilling Foreman and the Drilling Superintendent in conjunction with the Shell Drilling Engineer and the Shell Drilling Superintendent will have analyzed the trip time, borehole stability, well control issues, operational parameters, depth of hole, and time available to decide upon the contingency steps most appropriate for well securement, and a detailed procedure will have been worked up. The Shell Drilling Foreman then presents the procedure to the BOEMRE Field Representative aboard the drilling vessel for comment and concurrence.
Well Suspension Scenario 1 – Mechanical Plugging
1.    After determining that the well should be suspended under the assumptions described above, the Shell Drilling Foreman orders the Drilling Superintendent to stop all normal drilling operations and to commence circulating the hole.
2.    The driller completes circulating at minimum a full “bottoms up.”
3.    The drilling assembly is pulled out of the hole and a mechanical packer suitable to the last casing or liner size is made up on the bottom of the drill string.
4.    The packer is tripped in the hole, set approximately 200 ft above the last casing or liner shoe depth and pressure tested.
5.    Depending on actual water depth, sufficient pipe is pulled to enable having the end of the string 200 ft above the top of the packer when hung off in the wellhead via the hang-off sub (HOS).
6.    A full-opening safety valve and an inside blowout preventer (BOP) are made up in the top of the drill pipe, and one additional joint is added above these valves. The HOS is installed in the top of this joint. (The full opening safety valve is left in the open position.)
7.    The HOS assembly is run in the hole on drill pipe to land the HOS in the wellhead bowl.
8.    The proper hydraulic fluid volume to actuate the BOP stack is confirmed by the Subsea Engineer and the system operating pressure is checked. Pipe rams in the BOP are closed on the HOS profile. The drill pipe is backed out from the HOS and the landing string is pulled from the riser. The blind/shear rams are closed and locked above the HOS. BOP failsafe valves are all left in the closed position.
9.    The master bushings are removed and the riser spider is installed.
10.    The diverter handling tool is made up and the diverter assembly is laid down.
11.    The riser landing joint is made up into the slip joint inner barrel. The slip joint inner barrel is collapsed and the inner barrel is locked.
12.    BOP stack functions are blocked, and the LMRP connector is unlocked.
Shell Offshore Inc.    41    May 2011
Ice Management Plan    Beaufort Sea, Alaska
13.    The LMRP is pulled off the top of the BOP with the block motion compensator and riser tensioners.
14.    Once the Shell Drilling Foreman has ascertained that the LMRP is released from the BOP, he advises the Drilling Vessel Master that he is free to initiate (or continue) mooring recovery and departure procedures.
15.    The drill crew and Subsea Engineer pull the landing joint to surface. The landing joint, slip joint and riser are then layed down and the LMRP is secured on deck.
16.    The Drilling Vessel Master confirms with the IA that the Ice Alert Level has reached “red” status (ice hazard is due to arrive within 6 hours of completing anticipated mooring recovery time). The Drilling Vessel Master advises the Drilling Superintendent to have the Subsea Engineer shear guidelines loose from the top of the BOP guideposts and to retrieve the lines to surface.
17.    The drill floor and moonpool area are cleared and inspected in preparation for mobilizing the drilling vessel.
18.    All decisions and supporting facts are recorded on the Daily Report and issued to the BOEMRE, SIWAC, and the normal distribution list.

This is just scenario 1. There are four more scenarios with different possible events. Actually Scenario 1 isn't what happened because they only started drilling on Sunday.  According to this video on the Shell website, the first drill is a small (8.5" drill bit) that is a test to see that there are no obstructions or no unexpected pockets of gas. This drill is supposed to go 1300 feet down.  You can watch the video yourself.

And Sunday's ADN confirms this is a pilot drill.
By 6:30 a.m. Sunday, crews had drilled more than 300 feet into the ground for a narrow pilot hole that will eventually be about 1,400 feet deep, Shell spokesman Curtis Smith said. It's used to check for unexpected natural gas pockets, oil or obstructions before a wider hole is drilled.

With the Alert Levels chart in mind, I would note that Shell began drilling, according to the ADN,  at 4:30am Sunday and stopped on Monday.  Let's assume they stopped after 4:30am Monday.  That would be more than 24 hours.  If an ice hazard is more than 24 hours away, according to the Alert Levels, they should continue as normal.  But less than 24 hours away, they need to assess risk.   It's reasonable then to assume that they knew about the ice before they started drilling.  Shell spokesperson Curtis Smith is quoted as saying the wind shifted.
"The winds suddenly shifted and as far as we could determine, the ice could potentially impact our operations at that point," he said. The ice came within roughly 15 miles of the prospect, he said. It is moving at about .5 knots, or one-half a nautical mile per hour, he said. Shell is tracking the ice through satellite and radar imagery, and on-site reconnaissance.
They knew there was an ice pack not far away when they started drilling.  And sometime soon after they began drilling, the ice pack shifted its direction towards the drilling site.  Within 12-24 hours of the ice hazard's expected arrival time, they should be initiating risk assessments and making contingency plans.

They are under the gun here because they started late and, unless their September 24 shut down time is extended by the Interior Department, they've got less than two weeks to drill this year.  So, presumably they took a calculated risk and started drilling on the assumption the ice wasn't going to come their way.  The ADN article quoted above says they got 300 feet in the first two hours, but none of the articles said how deep they got when they stopped drilling.

Read more here:
OK, I admit, that was probably more than ten minutes if you did this seriously. But I won't put anything up on this tomorrow. If you go through this three times, I think things will start to make sense. Writing this all down helps me figure it out, so maybe to you'll need to take notes.


  1. Very informative. Will be back when I have at least 30 minutes.

  2. Thank you for aggregating all this information and putting it into bite-sized pieces. As always, I appreciate your thoughtful, well written and well sourced posts.


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