New Generation of Aluminum Drill Pipes Enhanced the ERD Performances in to the Huizhou Field – South China Sea

This paper is to present the results of a important effort and continuous performances improvement into the ERD challenging drilling activity. CACT-OG is the operator of Huizhou HZ 25-4 oilfield in South China Sea, the discovery made in 2005 consisting in a multiple oil bearing The HZ 25-4 field is pertinent to the PSC 16/19, central area of Pearl River mouth basin, and it is located 6 km southwest from the already operating HZ 19-2 platform, in a water depth of 102 meters. A total of 7 wells have been drilled so far, from HZ 19-2 platform in three different drilling campaigns. After the first three wells campaign, a number of technical challenges have been identified within them : ERD drilling experience level, excess torque and drag, shocks and vibrations, hole instability, hole cleaning and resulting pack off, high side force and casing wear, high ECD due to shallow TVD, losses due to the same leak off because of the increase of the measured depth (faults presence). For the second drilling campaign (2009-2011) a new methodological approach was planned including : a new engineering main curvature design, revised operations procedures and the implementation of newer used technologies such as: Aluminum Drill Pipes (first generation) and Continuous Circulating Devices,( e-cd eni technologies ).The results were extremely promising in term of drilling risks reduction and cost saving. A further enhancement step has been achieved with the third drilling campaign in 2012. Taking in consideration the achieved experience, and the lesson learned, the operation plan has been fine tuned revising the procedures, and introducing new Aluminum Drill Pipes of second generation, specifically designed for open hole sections. The new methodological approach and the deployment of the new generation Aluminum Drill Pipes (ADP #2 generation) have had as result both: an amazing improvement in drilling performances specially for 12 ¼ section and a consistent budget saving for the overall project. We can say finally that, this specially conceived drilling approach, and the new technology deployment, may represent an impressive step forward for improving the drilling performances in to the ERD wells, helping to maintain the economic threshold of the Development project.