Enhancing ROP Strategies

When deviated offshore drilling started in the 1980s a number of critical elements were identified. Some of these are wellbore stability, wellbore friction, and hydraulics. To handle wellbore cleaning a number of experimental flowlines were built in several countries. Around 1990 experimental data were used to design wellbore cleaning models. API RP 13D used in Section 2.4 gives a good summary. Mainly the outcome was how much drilled cuttings the wellbore could handle before the annulus packed off. This was coupled to a model that coupled cuttings production with ROP. API RP 13D provides a number of graphs where pump rate and ROP are selected based on drilling fluid properties, wellbore inclination, and wellbore dimensions. In addition, the standard also summarises the elementary physics around drilled cuttings. Although the standard is old, it has been updated a number of times and is giving a correct picture of the process.