Improved deepwater cementing practices reduce NPT

Over a four-year period, during which some 42 wells were constructed by BP, processes were developed to improve cement slurry design and reduce Non-Productive Time (NPT) during cementing operations on deepwater wells. Cementing best practices have been followed for many years; however, not all of these are applicable to deepwater operations, especially for the riserless sections. This article will review the results of developing slurry design practices, temperature prediction/mud removal modeling, and Subsurface Release Plugs (SRP). The cement blend used can have a profound impact on cost, both in design and supply logistics. As deepwater operations move farther from shore bases, the application of a systems approach should be considered to cover all cement design needs. The challenges vary from shallow water flow potentials to high temperature and pressure. Both conventional and foamed cement slurries can be successfully used when properly designed and placed.