What Does Spotting Procedure Mean?
The spotting procedure is the process of placing a small volume of pill or fluid in a wellbore annulus to free a stuck pipe.
Usually, oil-based mud is used as a spotting fluid, but where there is concern about mud disposal such as in offshore operations, the spots used are synthetic-based emulsions or water-based formulations.
The procedure can also be used to remedy a circulation loss problem. Knowing the calculations to spot the lost circulation material (LCM) pill in the exact location is paramount to the success of the spotting procedure.
Trenchlesspedia Explains Spotting Procedure
The spotting procedure is very useful in freeing differentially stuck drill pipes. The condition prevents the drill string from moving along the wellbore axis. The spot frees the pipe by covering the stuck region and breaking up the filter cake.
This allows the spot to migrate into cracks in the filter cake, and in between the pipe and the filter cake. This reduces the stuck area and allows the pipe to be pulled free. The speed in mixing and placing the spots are very important factors in successfully freeing the pipe.
For lost circulation, a lost-circulation pill made with flaked or fibrous material is designed to plug the perforations. One of the first signs of an inadvertent return is lower mud levels in the pits along with reduced pressure readings in the drill cab.
Having LCM products on location is a cost-effective way to remediate stuck drill pipes, inadvertent returns, and to reduce downtime.