The Use of a“Type Well”Concept Approach for Design,Feasibility,and Creation of a Technology Plan for Well Construction in a New Gulf of Mexico Deepwater Development

摘要

The deepwater Mars/Deimos field is located in the central region of the Gulf of Mexico(GoM)at~3000’ water depth.Mars was discovered in 1989 and production began in 1996 from Mars A,a 24 slot tension leg platform(TLP).The deeper Deimos,with significant hydrocarbon volumes,was later discovered below the original Mars production intervals.After years of development,the shallow target horizons have been severely depleted,whereas new discovery is still at significantly higher virgin pressures. Mars B Olympus DVA,a new 24 slot TLP,was justified following a holistic evaluation of the deeper discovery.This TLP represents the first brownfield development of a deepwater field in the GoM.The field life is~50 years,with a development plan requiring/80 independent completions across~60 hydrocarbon horizons,extending from 10,500=to 23,000=true vertical depth(TVD).Due to the limited number of slots and required number of completions,each of the boreholes has to consider future utility (i.e.,slot recoveries,slim-hole sidetracks,big-hole sidetracks and up-hole recompletions)as a fundamen-tal design requirement. The detailed well development concept design was kicked off in 2011,considering new design load scenarios due to more stringent regulatory and internal design mandates put in place.Previously used concept design was neither robust nor satisfy long term life requirements. A representative“Type Well”design concept approach was developed to holistically evaluate existing technologies and equipment feasibility against the new design mandates and to identify gaps.The type wells were analyzed in detail to ensure there were no design oversights and so design limit envelopes could be established.Subsequently,~20 new technology developments ranging from a high-pressure NACE tieback system to a reverse cementing tool were identified as critical to project delivery,and a multitude of unintended consequences resulting from the new well design were also identified in the process. The following paper describes the methodology used to create these type wells and examples of technology gaps identified.It also describes the key technologies developed and the domino effect as a result of their implementation.