Drilling the curve and lateral without changing the bit or BHA
configuration
An operator's effort to drill 6 1⁄8-in sections in Oklahoma's
Tonkawa layer of granite wash using conventional directional assemblies and PDC
or roller cone insert bits was producing disappointing results: Drilling the
curve and lateral in a hard and abrasive formation was limiting the length of
runs. And, to rotate in the lateral, a trip was required to change the
configuration of the conventional motor assemblies and standard turbodrill
assemblies. In addition, the OBM being used was decreasing positive
displacement motor (PDM) reliability. For these reasons, the operator sought an
assembly that could drill a section's curve and lateral without making a trip
to change the motor or BHA configuration.
Unique assembly increases drilling efficiency
To increase drilling performance and efficiency, Schlumberger
recommended the 4 3/4-in T1XL MK1 Neyrfor Delta high performance directional
turbodrill with 1.7° fixed bend and a Smith Bits 6 1⁄8-in K705
diamond-impregnated bit.
Schlumberger provided a Trackmaster OH whipstock and sidetracking tool
to enable access to the interval, the assembly would enable the curve and
lateral to be drilled without making a trip to change the motor or BHA
configuration. The Neyrfor turbodrill offers maximum horsepower and speed to
properly drive a diamond-impregnated bit while enduring OBMs and high
temperatures. The turbodrill's concentric turbine rotation and hydraulic
coupling reduces vibration, increasing MWD tool life.