New Strategy and Technology for Success in South China Sea on CACT Extended Reach Drilling Project

摘要

HZ25-4 oil field uses HZ19-2 platform for the development with five wells in which there are four extended reach horizontal wells (well HZ25-4-2, well HZ25-4-4, well HZ25-4-5 and well HZ25-4-6) and one extended reach directional Well (well HZ25-4-3) and one pilot hole Sidetracking from well HZ25-4-2 to explore the north shallow layer. After the completion of the third well, CACT-OG perform the further evaluation and study on those key areas including well trajectory design, well bore stability, ADP technology application, hole cleaning management and drilling fluids optimization. Utilize Rotary Steering System RSS for 16" build section in semi-catenaries to reduce tourtuosity, side force and casing wear. As agreed by technical evaluation, CACT agreed to use 5-7/8" aluminum drill pipe trial on 8-1/2" section of HZ25-4-3 and HZ25-4-6 to contribute to reduce casing wear, lower side loading and lower significant torque-and-drag. Develop appropriate measures and emergency procedures that applicable of triping and backreaming for HZ25-4-3 and HZ25-4-6 based on the difficulties and challenges met on previous 3 ERD wells. Meanwhile more accurate control of mud rheology and technical parameter for hole cleaning.CACT-OG finish last two wells unde budget while saving time successfully. It has been observed that this different drilling approach and technology has opened a new window on how to drill challenging ERD, and that is a key to improved drilling performance.