Pesca Pubblicazione scientifica Novel Workflows and Underreaming Measurements Reduce Risk by Supporting Decision Making FILONE TECNOLOGICO TEMA produzione e cattura RIASSUNTO This paper presents novel well construction work-flows and downhole measurements to improve the success rate with close tolerance casing and cementing operations. Drilling engineers routinely “flip the coin” and mentally take the risk of inferred underreaming. Considering the downtime that occurs across the industry such decisions are not sound. So why are they still taken? Routine decision-making shows a preference for riskier options even if safer options are available.This paper details workflows and operational measurements that lead to safer and more efficient outcomes. The psychology of controlling risk in decision making is extensively discussed. A recommendation is made for a controlled workflow incorporating ‘gates’ to break routines. This supports the drilling engineer to consciously focus on a key operational gate that is a cause of downtime or operational risk. Critically, this ensures riskier decisions based on inferred underreaming are challenged and gated before sequential well construction activities occur. A further level of support is provided by new downhole measurements. Wellbore diameter is measured using callipers and the downhole status of the underreamer is tracked using magnetic position sensors. Preferential work-flows incorporate these measurements and consequently operations such as the following can be managed more effectively: Running casing/cementing. Check final underreamed wellbore diameter. This reduces the risk of casing getting stuck or an out-of-spec cement job.Underreaming across a section or a trouble zone subject to radial shrinkage or hard stringers. Check wellbore diameter and verify underreamer status. This can trigger a repeated cycle of expansion and check effective deployment of the cutters and the status of the cutters. If cutters have extended yet calliper is below gauge this can indicate a radially- shrinking formation with time or cutters worn or missing.Activating a near bit-reamer. Check wellbore diameter and verify underreamer status across the section to ensure satisfactory underreaming of the section. This ensures the rat-hole is enlarged only when the section is at the predetermined hole size or any remedial work has been completed. This reduces the risks associated with rat-hole enlargement.Activate a secondary redundant reamer. Check wellbore diameter and verify underreamer status. This saves a trip to replace a worn underreamer and avoids premature or unnecessary activation.If cutters are extended yet calliper data shows undergauge then the cutters are worn or missing. Operational parameters such as flow, torque, weight etc can also be monitored and correlated. The paper concludes with a discussion and statistical analysis of risk factors that can be controlled using the work-flows and operational measurements. DATA Data di pubblicazione: 17/03/2015 AUTORI RASHEED WAJID THOROGOOD JOHN BERNARDINI JAIME ENTE DI AFFERENZA SMART WELLBORE SYS INCLUDING SMART REAMER RIVISTA SPE/IADC Drilling Conference and Exhibition, 17-19 March, London, England, UK