Drill through abrasive Cretaceous formation
PEMEX was drilling the 8 1/2-in intervals of onshore wells in the Terra
field near Villahermosa, Mexico, with positive displacement motors (PDMs) and
rock and PDC bits. Because the Cretaceous formationwhich was mainly
compressible mudstone with up to 40% abrasive chert nodulescaused rapid
wear of BHA components, multiple runs and many days were required to drill each
interval. PEMEX wanted to reduce drilling time for the interval and the number
of bits used.
Introduce turbodrilling system with diamond-impregnated bits in
The Schlumberger Integrated Project Management (IPM) team, working with
PEMEX, introduced the 6 5/8-in Neyrfor turbodrilling system with 8 1/2-in
Kinetic diamond-impregnated bits from Smith Bits, a Schlumberger company, in
Mexico to replace the PDM system and rock bits. The directional turbodrill was
configured with two integral body stabilizers, which were augmented with a
During the first turbodrill run, the directional plan called for
building angle, and the a KHi913 hybrid Kinetic bit with PDC cutters were used.
Later, the turbodrill was run with a K503QTB Kinetic bit designed for superior
performance at high rotary speeds in tough, abrasive formations.
Saved 96 hours of drilling time
Using the Neyrfor turbodrill and customized Kinetic bits, the
directional driller successfully built angle to 28° and reached interval TD
in less than 211 hours at an average ROP of nearly 7 ft/h. The time to drill to
TD was approximately 96 hours less than the time required to drill the interval
in offset wells with conventional drilling systems. Reducing the drilling time
enabled PEMEX to put the well into production sooner.