Retrieval of casing advancement system at 62m in Encamp, Andorra.

The Spanish drilling company Catalana de Perforacions SA was awarded a project in Encamp Andorra to secure the water supply for the new suburban area La Cabeca. The project was to drill 3 holes of Ø 508 mm casing to various depths to make sure they ended up with enough water to cover the future need.

Due to the difficult ground conditions at the site, part owner of Catalana de Perforacions SA, Josep Maria Casellas investigated the possibility for another drilling method as the first way that was selected had low rate of penetration and high wear on the drilling equipment.

Josep Maria Casellas:

“The drill rig we used for this project was our FOREMOST DR24HD with a double head rotation to install the casing. As overburden was really challenging on site with alluvial ground with granite boulders the service life of casing shoes was not good and only lasted between 3 to 14 meters. As we needed to drill over 60 m at our deepest hole, we needed to find another solution!”

Josep Maria Casellas contacted TerraRoc to see if there were any alternative method that they could adapt to this drill rig and site to increase production and decrease the wear on the drilling equipment.

TerraRoc understood the problem and explained that a rotary method is not suitable for this kind of overburden as the rock strengths (Mpa) is too high for rotary and in this case also very abrasives. To increase production on site TerraRoc suggested its well established and reliable QL120 hammer and model C with Symmetrix pilot for the casing advancement system. This casing advancement system allows you to drill both retrievable ring bit sets that allows you to retrieve the casing with ease, as in this case, but also permanent ring bit sets if ever the need would present is self in the future.

Josep Maria Casellas continues

“This time we needed a more efficient system then the standard casing shoes we normally use. We had to drill 3 wells with a diameter of 508mm and a depth of 30, 59.5 and 62 m alluvial ground with granite boulders in order to guarantee the water supply of the new urban area of La Cabeca in Encamp ,Andorra.”

To allow the Catalana de Perforacions SA to use their drill string that they already had and allow them to drill the required size of casing diameter, the hammer needed to be adjusted to consume more air. This adjustment was easily done to the QL120 as it has a plastic chock plug in the non-return valve of the hammer that can be change or modified to increase air consumption to make sure that you always have the right up hole velocity when needed to get the material out of the hole. In this case we increased the air consumption from it standard setting of around 47m3 to around 70m3 to get the right up hole velocity.

Whit this setup the client managed to have rate of penetration of 6 m casing sections per hour which welding 2 pcs of 3-meter sections that was welded together and put into places and welded to previous drilled section.

With Symmetrix casing advancement system Catalana de Perforacions SA managed to drill 92 m with the first ring bit set divided over 2 holes. Even though the ring bit set looked very good it was decided to replace it with the new ring bit set to be at the safe side. 

Josep Maria Casellas finish up with

 “Drilling experience with this equipment was great, outstanding, and fabulous. As our previous shoes only lasted a fraction compared with the Symmetrix system. m and the first ring bit set of TerraRoc reached 92m. We could probably drill another hole with the same ring bit set but we wanted to be cautious, even though buttons looked almost brand new after drilling granite. We will use it in a job site with less demanding rock.”

Congratulations to the crew of Catalana de Perforacions for this work. They have shown that the recovery of Ø508 casing of 62m depth is not a hard work despite challenging drilling when using a good hammer and a superior advancement system. And thanks for getting the opportunity to work together!