Recently in Saudi Arabia, a national drilling record was reached for the longest horizontal well drilled. A key technology for drilling such wells, which typically show a Total Depth (TD) in excess of 30,000 ft, was the use of extended reach horizontal drilling.
Drilling these wells required, among other things, a proper selection of drill stem products. With drill pipe accounting for most of the string length, choosing the right specification plays a huge role in overall drilling performance. With a lot of friction as the string is ran downhole, the ability to transmit torque to the bit is challenging and connection technology becomes critically important. Double shoulder connections place connections at par with the pipe body in terms of torque capacity and actually come with additional benefits. Not only do these connections transmit higher torque but they do it using a thinner steel envelop, which allows a larger internal opening for improved hydraulics. Furthermore, these streamlined connections can also come with reduced Outside Diameter (OD) tool joints which help keep the Equivalent Circulation Density (ECD) as low as necessary to maintain formation integrity.
Towards the end of 2010, a national record 32,136 ft measured depth well was drilled in Saudi Arabia using such connection technology, proper material grade selection and optimized pipe size selection. The well was then used for horizontal water injection into the reservoir in order to maintain reservoir pressure and optimize production. This paper will describe the challenges of this project and how connection technology, engineered material grade and pipe size helped address each of these challenges. The record well case history will form the base of this paper and authors will include a comprehensive section on the successfully selected connection, its performances as well as a summary of more recent results.