Coil Tubing Drilling
2002.11.10
Kyrholt, Skagafjordur
We´ve just started a new project involving directional drilling with the CT unit to 1800 meters. The top head rig goes in first, running 273 mm. surface casing to 24 m. after which we plan to go vertically to a kick off point at 400 m.
This is a pure experimental drilling supported by the Icelandic Energy Fund. At this particular location an abundance of 20 °C water has been discovered in the uppermost 250 meters, in a widely open fracture zone. Our task is to approach the fracture from a certain distance at 1500 to 1800 m depth, and hopefully we will hit water of adequate temperature for heating the nearby village of Hofsos.
2002.10.20
Kleifar, Olafsfjordur
Kleifar í Ólafsfirði.
Yet another sucess with Wassara. It penetrates through the Basaltic formations very smoothly and effortlessly. We are seeing definite savings in fuel and hours spent on those "Wassara jobs" completed so far. This time we quit drilling at 700 m. a bit disappointed with the results. The well yields 1 l/s of 54 °C water. Having done temperature, inclination and directional logging, we plan to drill further 100 to 150 m. some other time, since we are hoping to hit a rich aquafer of 70 °C.
2002.10.15
Lundur in Fnjóskadalur, North-Iceland
We are rigging the CT unit down at Lundur. It is getting cold again and without water we are getting nowhere. This summer has been like an exhaustive training program with some 440 meter of totally unstable formations and intrusion of cold aquafers to deal with. This is a slim hole drilling without the chance to run casing. In spite of those difficulties the CT unit is the most suitable equipment I´ve ever handled to deal with a situation like this.
2002.08.18
Lundur in Fnjóskadalur, North-Iceland
Last week we proceeded with last autumn's drilling at Lundur, N-Iceland. Having done few meters only we hit a thick loose intermediate layer, which keeps consistently caving in on us. Despite reattempted grouting injection, we have not overcome the problem yet. The positive side of the story is how convenient and easy the cementing operation goes with the Coil Tubing (CT).
2002.03.25
Husafell in West-Iceland
We have just completed the drilling of a Geothermal Well at one of Icelands most popular leisure facility, Husafell in West-Iceland. This hole was drilled at an angle of 30° from vertical in under the mountain, to 606 m. length.
The drilling site at Husafell.
Due to water supply problems we commenced drilling with conventional air DHD, but at 324 m. we decided that ROP and compressor fuel consumption were no longer acceptable.
Drilling at full speed.
Having changed over to Wassara, ROP reverted to 20 to 25 m/hour. This well yields 26 l/sec. of 62°C water (412 GPM, 144°F).
Sparkling spring water. 26 l/sek., 62°C.
2002.01.15
Hjalteyri, near Akureyri
For the 2nd time the Wassara DHD has revealed its superiority, this time however with conventional top head rig. During the summer 2001 we did a research well near Akureyri but the air DHD drowned at 170 m. due to heavy intrusion of water. Having done further 99 m. in 100 hours with a TCI roller bit, it was decided to postpone further drilling and wait for the Wassara. Having done som trial and error adjustments on the Wassara hammer we managed to penetrate from 269 to 463 m. in about 11 hours only.
We learned a lot about this equipment's characteristic at this time, I think it could penetrate the Icelandic basalt at some 50 m/hour if so adjusted internally.
2001.11.30
Lundur, near Akureyri. Conclusion
This drilling, although only 200 meters, has further enhanced our believe in this technology after the experience already gained in Oslo.
This technology has come to stay.
The Wassara DHD is an outstanding piece of equipment and a major contribution to the drilling of medium to hard formations. The Coil Tubing has superior advantages, most visible however with deeper drilling.
Per H. MoeFridfinnur K. Danielsson
2001.11.24
Lundur, near Akureyri
The equipment has now been taken down and remowed from the site. As can be seen on the pictures below the entire package consists of:
- Injector and hydraulic system, trailer mounted.
- Reel, holding 2500 m. of 60 mm. tubing, mounted on a special built trailer.
- Pumps and workshop containers, trailer mounted
- 400 KVA genset, trailer mounted
- 2 x 20 ft. control and crew cabin.
2001.11.21
Lundur, near Akureyri
It was finally on Saturday night the 17th, that we ran in the hole with the Wassara DHD and the Coil tubing. On Sunday and Monday 18th and 19th we drilled from 201 m. to 404 m. ROP was held at some 25 m/h, but although the Wassara would penetrate substantially faster we held it back to avoid overloading the annulus.
On Monday afternoon the 19th we decided to pull out at 404 m. Shortly after that we lost the water supply as the water froze. Bearing in mind that the season is late November, and that the water supply at this particular location depends on weather condition, we decided to postpone further activity until later.
It is, however, to be noted, that we see no problems associated with drilling in cold climate provided the water supply is reliable.
2001.11.16
Lundur, near Akureyri
During the last few weeks we have been rigging up and preparing our first drilling at Lundur, N-Iceland. We drilled the "start hole" to 200 m. with a conventional top head rig, but decided to incline it 15° from vertical as we hope there are better chances to hit geothermal water from under the mountain.
At 128 to 130 m. depth we had some problems with the hole caving in plus a substantial water aquafer 14 °C. The good old remedy of injecting cement grout into the problem zone worked just as usual. The well is now ready for running in the Wassara hammer and the Coil Tubing.