If you think that a single rig that drills with single joints of range III pipe can’t match a larger triple rig in drilling 20,000-ft horizontal wells, Precision Drilling engineer Harold Griffin wants you to think again. As his presentation at the 2010 IADC/SPE Drilling Conference in New Orleans on 4 February showed, in some cases, it can even outperform a triple rig.
The single rig he’s referring to is the Precision Drilling Super Single, particularly the larger AC electric “stretch” model introduced in 2009. Other models of the rig are the slant, light, electric and mobile.
In 2009, the Stretch Super Single was sent into an area to drill 20,000-ft horizontal wells, with 10,000 ft vertical and 10,000 ft horizontal. Triple rigs in the same area drilling the same-type wells had to set back 20,000 ft of pipe while tripping. The super single met the hookload requirements and had no setback limits because pipe is laid down with the pipe arm on every trip.
Precision conducted a study to compare the performance of the single versus the triple rig. “The Stretch Super Single on average was 4.11 days faster on rig-up and on average 8.29 days faster from release to spud,” Mr Griffin said. These observations were also made:
• A triple rig trips pipe faster than a super single.
• The super single made connections faster while drilling.
• The super single made connections slower tripping.
• The super single moves and rigs up faster.
Mr Griffin also pointed out that, in addition to enhanced performance, one of the main advantages of the super single is that it improves safety on the rig floor because “a floorhand on a super single might only touch tubulars when he is measuring pipe.” He added that Precision’s safety record has improved from 6.38 in 2005 to 1.89 in 2009, “and we think one of the main reasons for that is the safety benefits of the super singles.”
As of November 2009, Precision has 53 super single rigs in its fleet. The company has drilled more than 16,750 wells with this type of rig since the first was built in 1990.
More information about the super single rigs can be found in IADC/SPE 128201, “Evaluation of Precision Drilling Super Single Performance.”