While you are sliding with a motor assembly, you may consider backreaming one time at least. The reason is that you will smoothen the well bore and it will help you when you run casing/completion or when you trip back in hole with another BHA.
Image from the internet
This is the example based on my experience, I drilled a 12-1/4” section with mud motor 1.5 degree bend and I slid 30 stands without back reaming. When I finish my motor run, I circulated hole clean and pulled out of hole to change to a rotary BHA. When I tripped back in hole, I could not pass where I started sliding therefore I ended up with reaming down all the way to the previous TD. It took me 4.5 hours extra. After I learned this event, I changed my drilling practice. I back ream at least 1 times every slide I made and I rarely had the problem while running casing/completion or tripping back in hole.
In my opinion, you should not use this practice if you are drilling into very soft formations because you will easily lose your angle.
PS, this is my opinion based on my experience. Please ask your boss again before back reaming .
I believe back-reaming changes the direction of stresses and can create break-outs. Its just a temporary solution and hence shall be avoided unless there is no any other way to deal with hole or hole requires it seriously.
You need to look at the torque. If the torque while you are back reaming is not so high, it should not change any stresses or causes you a trouble. However, if you get stuck, applying torque in the drill string with tension will reduce tensional strength of the drill string so you can have a bad day.
can anyone provide me the formula to calculate that how many feet of drilli line should be slipped not cut (keeping in view mast length) so that pick up point should be shifted safely
You should know the tone-mile of the drilling line. You can check from the specification from the manufacture which will tell you how many feet that must be cut for certain amount of tone-mile.
Backreaming killed bits untimely.
Anton,
I’ve never been experiencing about bit damaged while backreaming at all.
And what do you think, what is the top speed of backreaming (meters per hour) when I drill 6″ horizontal section and use 3-1/2″ DP S-135 with Weatherford BHA (RSS – point the bit)? Thank you.