When is it advisable to use coiled tubing drilling in comparison with conventional  methods?

 

Sticking is an acute problem of directional drilling, which can result in losing the whole bHA. Some companies introduce centering  elements in their bHAs. Is it an effective way to cope with the problem of sticking? What else can be used?

 

To what degree should the pumping fluid be purified for the work with directional drilling system? Usually the specification  says that the concentration of sand is less than 1 per cent, but nothing is said about the maximum particle size, though it is obvious that the bigger the particle is, the less the abrasive working life of the bHA is. What are the recommendations regarding the maximum particle size in the clean fluid?

 

Answers to these questions are provided in the article.