In order to meet the demands of ever more challenging wells that push the boundaries of the drilling envelope, technical developments have taken place throughout the industry, including drill stem products and more specifically connection technology, resulting in the introduction of the 3 rd Generation Double Shouldered Connection (3 rd Gen DSC).A key design objective of this 3 rd Gen DSC is to improve connection make-up and break-out speeds relative to the 2 nd Gen DSC. This was achieved by incorporating the first double start thread design for drill pipe, resulting in a significant reduction in make-up/break-out times. In addition, the 3 rd Gen DSC also provides increased mechanical and hydraulic performance as well as a step change in fatigue resistance.A recent trial was performed in Southeast Asia in order to directly compare both the 2 nd Gen DSC and 3 rd Gen DSC, both utilized on 4 inch, 14.00#, S135 drill pipe. A total of 9 wells were drilled from the same platform, 5 utilizing 2 nd Gen DSC and 4 utilizing the 3 rd Gen DSC. Make-up and break-out times for both connections were recorded during normal drilling operations. Analysis of the data quantified overall time savings when using the 3 rd Gen DSC.A secondary benefit of the 3 rd Gen DSC became apparent during the subsequent inspection, which saw a significant reduction in connection damage in comparison to 2 nd Gen DSC. This reduction in the number of repairs was considered to be a direct result of the connection design.The paper provides a comparison of data obtained from similar well sections drilled by both 2 nd Gen and 3 rd Gen DSC and summarizes lessons learnt from the use of the 3 rd Gen DSC and the benefits recorded in relation to time savings, reduction in connection damage and associated rework costs.
SPE 146616
Challenges of drilling in ThailandThe Gulf of Thailand is rich in history with over 40 years of offshore drilling experience. In 2005, Unocal Thailand Limited and Chevron Offshore Thailand Limited who were major operators in the area merged, combining their experience and individual evolution of drilling practices within the Gulf of Thailand (GOT). Currently operating under two different identities; Chevron Offshore Thailand Limited (COTL) and Chevron Thailand Exploration and Production (CTEP), both entities follow the same approach to drilling in the region. Wells are designed to be executed with minimal cost impact and in the shortest possible duration. Due to the marginal reserves and steep production decline, the strategy is to drill and complete as many wells as possible to not only complement the production decline but also increase the overall supply of natural resources to the Kingdom of Thailand.Based on the field's requirements a well bore was designed as a 3-string slimhole monobore, which could be completed in 4.5 days. However due to the increasing demand in deliverables and the drive to achieve reserves at greater depths, operational complexity increased which in turn lengthened the total days per well to 6.0 days.In order...