26 |
Oilfield Technology
June
2016
nearly 150% in sandstone – while requiring less mechanical specific
energy (MSE) than previous generations of PDC cutters.
With the launch of the product at the end of last year, the results in
the lab were validated with performance in the field.
Casestudies
NorthDakota
An operator in the Bakken Shale, North Dakota, USA, had an objective to
drill the 5⅞ in. lateral section with a single BHA whilemaintaining high
ROP. Regional design engineers suggested a five-bladed 5⅞ in. Tektonic
bit with 16mmReflektor mirror-finish cutters would be best suited for
the formation. The bit, matched with an Agitator™ systemand an ERT™
power section that was tailored for the Bakken, drilled the lateral section
with an average ROP of 143 ft/hr – a 34% increase over the offset average
and an operator record for a lateral section. The bit completed the 9293 ft
interval in a single run, too, besting the offset interval average by 62%.
Texas
In the Eagle Ford Shale, Texas, USA, an operator wanted to drill
the 12 ¼ in. surface interval in a single run with high ROP while
maintaining a good dull condition. The regional design engineer
offered a six-bladed 12 ¼ in.
Tektonic bit with Reflektor
cutters that were well suited
for high impact damage
applications for use on an
8 in. 7:8 lobe 4.0 stage drilling
motor with a 1.5˚ fixed-bend.
The bit drilled from 125 ft to
3980 ft in six hours, averaging
an ROP of 642.5 ft/hr. This
was 59% faster than the best
competitor offset ROP and an
operator record in the region.
The bit was pulled with an
impressive dull condition of
0-0-NO-A-X-I-NO-TD.
Angola
In the Malongo West field in
Angola, a directional driller
had an objective to drop
inclination from 13.24˚ to 0˚
and vertically drill to TD with competitive ROP in the 12 ¼ in. section.
For use on a rotary steerable system, the regional design engineer
provided a six-bladed 12 ¼ in. bit with 16 mm cutters. Though lithology
predominately consisting of halite with a few anhydrite stringers, the
bit drilled the entire 1931 ft section to TD in a single run. With an ROP
of 77.2 ft/hr, the bit provided 58% greater ROP compared to offset
averages and set a new field record.
Oman
Tektonic bits have also been proven in the Middle East.
In the 12 ¼ in. vertical section in a well in Oman, an operator had an
objective to drill to TD with competitive ROP using a drilling motor.
The regional design engineer recommended a five-bladed 12 ¼ in.
bit with 19 mm cutters to get the best performance through the
carbonate and shale formation. After drilling the entire 2484 ft vertical
section with an ROP of 138 ft/hr, the bit was pulled out of the hole in
excellent condition (0-0-NO-A-X-I-NO-TD). This run was a new field
record, with 4% greater ROP and a 14% longer interval than the best
offset.
Also in Oman, a customer wanted to drill the 12 ¼ in. vertical
section in a single run at a high ROP using a rotary assembly. For a
formation consisting of limestone, dolomite, shale and highly abrasive
sandstone sequences, the regional design engineer provided a
six-bladed 12 ¼ in. bit with 16 mm cutters along with a ReedHycalog
NV near-bit stabiliser. The bit delivered a record-setting performance,
drilling the entire section and outperforming the matrix bits that
were the standard choice for the section. In just over 169 hours, the
bit drilled 8553 ft and set a field record for ROP at 50.5 ft/hr – a 23%
improvement over the field average ROP.
Another six-bladed 12 ¼ in. bit with 16 mm cutters was
recommended for an operator to drill a sequence of shales and
carbonates, with the hardness of the carbonates increasing with the
depth. The bit drilled the entire 8136 ft vertical section in a single
run with an average ROP of 75.4 ft/hr, providing a 71.4% increase
over the median offset ROP and setting a new field record. The bit
exceeded all customer expectations, and on the surface it was graded
3-4-WT-A-X-I-BT-TD.
China
In North Xinjiang Province, China, an operator wanted to drill
an 8½ in. vertical section on a water-basedmud systemat a competitive
ROP to reduce drilling days, improve drilling efficiency, and save overall
costs. Based on thorough offset analysis, the regional design engineer
recommended a specially designed five-bladed 8½ in. bit with 19mm
cutters. In its first run, the bit set a newROP record for the area, drilling
2070 ft through claystone, sandstone, and conglomerate formations with
traces of tuff and andesite. With an ROP of 34.32 ft/hr, the run was 108%
faster than average and 50% faster than the best offset. Using a Tektonic
bit saved the operator a total of five days and approximately ¥200 000,
and the dull condition was such that the bit was rerun on another well,
offering further savings.
Summary
New records for performance and drilling efficiency are being set
as the Tektonic drill bit platform expands around the globe. New
combinations of features and elements for Tektonic bits are helping
to increase performance in other challenges, including deepwater
and hard rock applications. And as the industry demands greater
performance and efficiency in its operations, drill bits with designs
tailored for the application and environment are an essential part of
the equation.
Figure 1.
The Tektonic bit platform
is designed for efficiency, speedand
reliability.
Figure 2.
Tailored features, such as cutters and flowguides, optimise
each bit for the application.
