DFDP-2 Calamity resolved! Mostly.

Rupert Sutherland, GNS Science and Victoria University of Wellington
John Townend, Victoria University of Wellington
Virginia Toy, University of Otago

A lovely morning at the site. 13/11/14. Photo R. Sutherland.

Successful fisherman, Richard. 
Photo: R. Sutherland 13/11/14

Yesterday, after it was clear that the drill had snapped and been left at the bottom of the hole (489 m depth), the drillers flew into action, quite literally. They went up to New Plymouth in their plane, obtained a fishing tool, got it back to our site, deployed it, attached to the lost drill, pulled it back to the surface, and took it apart. This was all complete by 4 a.m! It was an impressive effort.

The drill bit was damaged, but still in one piece. The bearings were broken. It was also badly worn, so must have been cutting a hole that was at least one cm too narrow. We think this explains the damage to the bottom stabiliser, but are still piecing together the facts.

Our next challenge is to check the integrity of all components and obtain new stabilisers. We hope to be drilling again very soon.

Everyone on site is now familiar with what a bottom-hole assembly (BHA) looks like. If you want to watch an explanation of the various parts and what they do, see our youtube video:


https://www.youtube.com/watch?v=A6gLpzR8mlI

Comparison of broken drill bits. The bit recovered today (left) is badly worn and the bearings are loose. The bit dropped previously (right) has broken teeth and has cones jammed together. Photo R. Sutherland. 13/11/14.

Broken pin with stripped thread. This is the top of the recovered piece of BHA. Scratches visible at the top of the photo are from the fishing operation. 
Photo R. Sutherland 13/11/14.

Driller, Paul, is standing next to the fishing tool and a part of the recovered bottom section of the BHA. The drill collars beneath are part of the upper BHA. 
Photo R. Sutherland 13/11/14.

Primary funders of the DFDP-2 project are: the International Continental Scientific Drilling Program (ICDP), the Marsden Fund of the Royal Society of New Zealand, GNS Science, Victoria University of Wellington, and the University of Otago.

DFDP-2 @ 489 m: Calamity! Again!

Rupert Sutherland, GNS Science and Victoria University of Wellington
John Townend, Victoria University of Wellington
Virginia Toy, University of Otago

Fresh snow in Whataroa. Drill site is up the valley on right of photo.
12/11/14. Photo R. Sutherland.

Misfortune struck in the early hours of Wednesday morning. Drilling progress had slowed the previous day, and then it totally stopped. We had reached 489.5 m depth.

The drill was removed from the hole and we got a surprise: the drill bit was missing. So was the bottom 7.5 m of the bottom-hole-assembly (BHA).

Steps to recover the lost BHA piece are in motion. We know how to fish it out from our last experience.

Crossover (left) with stripped thread and a broken fragment inside.
It should look like the male thread on the right.
Note the stabiliser just above it.
12/11/14. Photo R. Sutherland.

Worn stabiliser. 12/11/14. Photo R. Sutherland.

Close-up of stripped thread and broken fragment still engaged.
12/11/14 Photo R. Sutherland

 The loss was caused by equipment failure: a broken thread. It is the same section of drill collar that bore the full impact when the BHA was previously dropped to the bottom of the hole, so it may have had a weakened thread. However, there are also signs that drill bit failure contributed to this incident.

The science team noted anomalies in the hours before the incident. Steel shavings were collected (damage to stabiliser and bit?) and traces of hydrocarbons detected (grease from the threads?). The bottom stabiliser is badly worn at its base, suggesting the hole was not in gauge (it was too narrow). It seems that the drill bit may have started to fail at least 8 m before BHA separation occurred.

Wireline logging is underway. It will help us understand the state of the hole and what happened.

We hope to be drilling again in a few days.

These little fellas really didn't care about our woes. They are always happy to see us.
Photo R. Sutherland

Primary funders of the DFDP-2 project are: the International Continental Scientific Drilling Program (ICDP), the Marsden Fund of the Royal Society of New Zealand, GNS Science, Victoria University of Wellington, and the University of Otago.

DFDP-2 @ 430 m: Drilling hole again

Rupert Sutherland, GNS Science and Victoria University of Wellington
John Townend, Victoria University of Wellington
Virginia Toy, University of Otago

It certainly took longer to get drilling again than we had hoped, but we are now making steady progress. We started drilling again at 7 pm last night and passed 430 m depth this morning.

The delay was caused by annoying fragments of metal that were still in the borehole after we had recovered the main BHA.

Fishing tool with a strong magnet inside it covered in fine metal shavings 9/11/14.
Photo: R. Sutherland.

The most elusive object was a weight that normally resides at the bottom of the winch rope (just below the flag, see photo of the new one). It was eventually retrieved using a strong magnet in a steel pipe (see photos).

Fishing tool with our last catch. 9/11/14. Photo: R. Sutherland.

The BHA and a nice new tricone drill bit were installed yesterday and we are now making good progress. The science team and drillers are very pleased to have put the dropped BHA drama behind them.

Flying the flag again 10/11/14. Photo: R. Sutherland

Primary funders of the DFDP-2 project are: the International Continental Scientific Drilling Program (ICDP), the Marsden Fund of the Royal Society of New Zealand, GNS Science, Victoria University of Wellington, and the University of Otago.

Happy drillers

Rupert Sutherland, GNS Science and Victoria University of Wellington
John Townend, Victoria University of Wellington
Virginia Toy, University of Otago

Broken drill bit recovered from the lost BHA. 5/11/2014 Photo R. Sutherland.

Happy drillers: Luke Valour (left) and Tony Lyons (right). 5/11/14 Photo: R. Sutherland.

Was it great to see that smashed up drill bit finally recovered? Yes it was!

It took longer than we thought to get everything on deck, but finally the fish was landed, cleaned, and checked. The drill bit was a write-off (see photos), but the other components were surveyed by an engineer (who arrived by helicopter) and they are apparently undamaged — they are very solid steel.

Minor fishing operations continue as we recover remaining small fragments, but we are nearly there. We will collect wireline logs tonight. Tomorrow, a new drill bit will arrive, and a new BHA configured. We have an engineer’s report into the original winch failure and repairs will be complete tomorrow.



Hail on us, sunshine everywhere else. 4/11/14 Photo: K. Sauer

Check out our new video... Minerals and Alpine Fault drilling

Primary funders of the DFDP-2 project are: the International Continental Scientific Drilling Program (ICDP), the Marsden Fund of the Royal Society of New Zealand, GNS Science, Victoria University of Wellington, and the University of Otago.

Landing the fish

Rupert Sutherland, GNS Science and Victoria University of Wellington
John Townend, Victoria University of Wellington
Virginia Toy, University of Otago

Photo: R. Marx.

The BHA — 7400 kg of steel — was lost to the bottom of the hole over a week ago. The weather packed up shortly afterwards. It was a pretty grim week to be a scientist or a driller in Whataroa. But, the science and weather forecasts are good.



Photo: R. Marx.

The drillers have been fantastic. They methodically and calmly worked at the problem, systematically cleaning out loose materials and deconstructing the top of the lost BHA. It is amazing how they can picture and even feel what is going on 324 m underground. Over the last 10 days they have recovered wire rope, a shackle, a piece of wet rag, the top and then the bottom of the heavy steel hauling plug. They grabbed stuff with all sorts of special tools and even lifted the whole assembly by 5 m at one point. The mood has steadily improved.

This morning, just as the hail set in, they successfully latched onto the top of the BHA. By lunch time, the top of the ‘fish’ was visible at the surface. Tomorrow morning it will be landed. Then there will just be some minor bits of trash to clean up. Hopefully we will be drilling again by Thursday.



Drillers landing the fish. Photo: R. Marx.

Primary funders of the DFDP-2 project are: the International Continental Scientific Drilling Program (ICDP), the Marsden Fund of the Royal Society of New Zealand, GNS Science, Victoria University of Wellington, and the University of Otago.

DFDP-2 @ 396 m: Calamity! Dropped bottom-hole-assembly (BHA)

Rupert Sutherland, GNS Science and Victoria University of Wellington
John Townend, Victoria University of Wellington
Virginia Toy, University of Otago

Drill site 22/10/2014  Photo J. Thomson

We removed the drill from the hole last Thursday (23/10/2014) at a depth of 396 m, so that we could survey the hole and reconfigure the drill. The wireline logging survey went smoothly. It is about 56 degrees Celsius near the bottom of the hole.

Wireline logging tool. Photo: J. Thomson.

The drill bit was found to be worn and the hole had reached 12° off vertical. The deviation was caused by mechanical interaction between the drill and the dipping rock fabric. At least it was heading in the right direction (northwest, towards the fault).

Worn PDC drill bit. Photo: R. Sutherland

 Tricone bit, collars, and stabilisers. 

24/10/2014 Photo: R. Sutherland.

The drilling team reconfigured the drill pipe and switched to a new drill bit. This time we used a tri-cone type of bit. The bit is attached to heavy, rigid ‘collars’, and wider pieces of pipe called ‘stabilisers’ that centralize them in the hole. The entire ‘bottom-hole assembly’ (BHA) weighs 7400 kg in mud and is 72 m long. It is connected to the surface with steel drill pipes.

Fishing tool and fragment of
recovered wire rope. 27/10/2014
Photo: R. Sutherland.

Calamity struck at 13:09 last Friday afternoon (24/10/2014), just before the Labour Day long weekend. A wire rope snapped and the entire BHA dropped down the hole. We are very relieved that nobody was hurt. An independent technical investigation is being conducted by an engineer and we await his findings.



Our immediate strategy is to try and retrieve the BHA from the hole. This process is known as ‘fishing’. The BHA weighs 7.4 tons, so the first step in fishing is to extricate anything preventing a good grip. The drillers were successful in fishing out of the hole some broken fragments of wire rope and some of the top fixings. They are now working to establish whether they can lower a socket over the top of the BHA. If that is possible, they will use a special tool used in the oil drilling world to lock onto the BHA and lift it back to the surface. This tool is being transported from New Plymouth.

Fishing tool 30/10/2014  
Photo: J. Townend.

What does this mean for the project? It is certainly going to delay progress, but everyone is working hard to recover and continue. While fishing operations are underway, we have been analysing the data collected so far and documenting our preliminary findings.

If the BHA cannot be retrieved, we will cement it in place and side-track (deviate) the hole above it. This will mean re-drilling about 100 m of hole, but we can re-use most of the steel casing already installed.
We had expected delays of some sort from the outset, so we have contingency built into our scheduling. The delays so far mean that the project will continue into December, and we are very much hoping to get back on track so that we can finish before Christmas.

Nobody said it would be easy!



Check out our new video that shows you what a bottom-hole-assembly actually looks like before it is assembled and put in the hole...

Check out our video that describes the purpose of the DFDP project...

Some comedians did a parody of the safety of our project last week, but is it safe? We think it is, but don't take our word for it. See the video made by the Chairman of our independent Safety Panel...

See also:
The DFDP-2 wiki pages


Primary funders of the DFDP-2 project are: the International Continental Scientific Drilling Program (ICDP), the Marsden Fund of the Royal Society of New Zealand, GNS Science, Victoria University of Wellington, and the University of Otago.

DFDP-2 @ 360 m: solid rock since 240 m

Rupert Sutherland, GNS Science
John Townend, Victoria University of Wellington
Virginia Toy, University of Otago

A lot has happened since our last update. We have completely reorganised the site and positioned a new drill rig over the borehole. We’ve tidied up all the big steel pipes, and the Washington Drilling trucks, rig, and drillers, have left. We’ve hoisted the flags on our science facility and are getting down to some serious business in solid rock.

Onsite science facilities 22/10/14. Photo R. Sutherland.

The main phase of open-hole drilling began at 3 pm on Sunday 19 October, and we had reached 360 m depth by 7 am this morning. Our rate of progress varies between 1 and 4 metres per hour. We are now working in shifts around the clock.

The geology group is collecting rock cuttings made by the drill bit and transported to the surface entrained in the drilling mud. The mud travels down the centre of the drill pipe, out through the bit, and back up to the surface. It emerges at 25°C, but we know from downhole measurements that the temperature at the bottom already exceeds 50°C.

8.5” PDC drill bit. Photo: R. Sutherland.

We have three main science tasks at the moment. The first is to document drilling rates and mud characteristics. These measurements tell us about rock properties, fluid pressures and downhole temperatures. The second is to use wireline tools to survey the borehole during breaks in drilling. Finally, we are carefully analysing the rock cuttings to determine when to stop this phase of open-hole drilling and to start collecting rock cores.

Drill rig and mud pump 22/10/14. Photo R. Sutherland.

Primary funders of the DFDP-2 project are: the International Continental Scientific Drilling Program (ICDP), the Marsden Fund of the Royal Society of New Zealand, GNS Science, Victoria University of Wellington, and the University of Otago.