Drilling mud upward velocity modelling in Ansys CFX software

Drilling mud has various functions, one of which is to carry cuttings to the surface. All other things being equal, the removal of cuttings is characterized by the upward velocity. This paper simulates the rheology of polymer-glycolic non-dispersing mud (in particular viscosity) to achieve the required upward velocity in the «Ansys CFX» software. The viscosity of the mud varies from 6 to 12 mPa·s, on production casing drilling in Arctic conditions. The results of the study showed that for such conditions, the viscosity should be in the range from 6 to 8 mPa·s.

7-inch Casing While Drilling CWD With Retrievable Bottom Hole Assembly BHA

Casing drilling technology, as an alternative to conventional drilling, has been known for a long time. This method is mainly used for wells with geological complications, such as lost circulation or wellbore instability of various nature. By using drilling on a string for a section or part of it, the problem interval is immediately cased, eliminating the time spent on additional operations, such as pulling the bottom hole assembly (BHA), wiper trips and running the casing. Thus, this allows to reduce the time for well construction, reduces the risk of accidents and non-productive time associated with the complication zone. Casing drilling has become widely for drilling vertical surface conductors and technical casing with a drillable shoe, as well as for drilling with retrievable BHA in inclined sections for 324- and 245-mm casing. The aim of this work was to perform directional drilling on a 178mm production casing in an interval where the client had geological problems associated with running casing due to a zone of rock collapse. The uniqueness of the task lies in the fact that no one in the world has yet performed drilling on a casing with a building inclination and landing into a horizontal plane. It was necessary to follow the designed well trajectory, to build inclination from 67 to 85 degrees with the planned dogleg severity of 1 degree / 10m.