Technical Committee Drilling and Completion Technology

Optimizing ROP in Formations Difficult to be Drilled

In Northern Germany drilling engineers encounter the problem of low rates of progress (ROP) while drilling in the geological formations middle and lower Bunter and Keuper. The ROP is quite low in comparison to other regions, e.g. the North Sea.
The performance date of more than 100 wells that were drilled in Northern Germany during the last 10 years were studied by statistical methods. The data under investigation comprise more than 1,000 bit runs. The results of the data analysis were used to set up a prognosis with respect to the potential to improve drilling performance in the target horizons by combining improved drilling bits, more powerful downhole motors, and increased bit hydraulics. For the two Bunter formations a special impregnated drilling bit was conceived, applied, and improved with noticeable success.