Hole-Cleaning Optimization: A Case History from Three High-angle Wells in Austria

Abstract

AbstractHole cleaning is a critical part of ensuring successful execution, as wells become more challenging to drill and well designs more complex.The philosophy of model, measure, and optimize was applied to the task. Three consecutive, similar, and co-located high-angle (85–95°) 8-½-in. sections were drilled, which provides an objective comparison of the efficacy of effective and consistent drilling practices, teamwork, and engineering.The operator's challenge was to: Mitigate the risk of stuck pipe during drilling and tripping,Reduce the need for backreaming to reduce potential for excess wellbore and down-hole tool damage, andDeliver efficiency savings.The primary aim to execute these deliverables meant ensuring effective hole cleaning while drilling and prior to tripping to facilitate a clean, uneventful trip out of hole.During the planning phase, the hydraulics system and the torque and drag were initially modelled to give a baseline measurement to assess the drilling operations and were continually updated to ensure accuracy. Additionally, modelling highlighted a major contributor to previous hole-cleaning issues from the drilling fluid.During the execution phase, drilling and tripping practices already in place drew particular scrutiny, which lead to a discussion between the operator and service provider. Proactive operator leadership led to collaboration with the service provider to review the practices and procedures. This collaboration resulted in presentations for rigsite personnel to emphasize the importance of standardized procedures and to lead to subsequent improvement in each well.This case study investigates each section's performance and the positive results from procedural improvements, mud-property optimization, and cost savings of proper hole cleaning, which resulted in the following:No stuck-pipe/lost-tool incidents,Ability to pull on elevators at the final TD of the third well,63% improvement in tripping-out time at TD (comparing Well 3 to Well 1, 15 hours compared to 40-½ hours), and15% improvement in liner-tripping time.