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.

The Neyrfor turbodrill also provides superior borehole quality and is capable of drilling from the face of the whipstock, which saves rig time that might otherwise be spent on dressing the whipstock face and drilling far enough to get the BHA in the hole.

Drilling the curve at record breaking ROP

The Neyrfor Delta turbodrill and diamond impregnated bit assembly set a field record by drilling the 648-ft curve interval at a 14°/100 ft buildup rate and 2675-ft of the lateral interval in 1.83 days at an average ROP of 19.84 ft/h on the first run. After making a bit change run, the assembly drilled the remaining 1,681-ft of the lateral at ROP of 21.83 ft/h. When compared with the best performance in an offset well, the operator's well was completed 3.7 days faster, setting a new performance benchmark for the field.