Planning for a Necessary Evil in Deepwater Operations:Remedial Cementing

摘要

Drilling operations are presented with challenges for both normal and complex wellbore environments with a focus on minimizing nonproductive time while successfully achieving the well objectives.In some cases,it is likely to reach the well objectives and remedial cementing may play a significant part whether it is due to exploration or wildcat-type wells,complex well construction,or the geological uncertainties. As a necessary evil,being able to plan for contingencies and success when faced with remedial cementing applications can reduce the potential replication of treatments and improve the extent of nonproductive time. When these situations arise during deepwater operations,there are challenges beyond the traditional cementing scope of work such as multiple temperature and pressure gradients,subsea equipment,and large-bore tubulars.Drilling deeper these factors may also include lithology,wellhead clearances,stuck pipe,failure of barriers,and/or an unstable well.Furthermore,traditional service tools find limited success with remedial operations in large-bore casing/tubulars,often requiring alternative solutions,including pumping through bottom hole assemblies,using inflatable packers,and developing other non-traditional placement techniques. This paper will present methods to improve the success of cement placement while performing remedial cementing operations in an effort to reduce nonproductive time and execute common contin-gency planning.In addition,specific well situations and events executing these methods will demonstrate the impacts to remediate the necessary evil.