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SpecialReport: Drilling Innovations
fatigue at 65 or 75 rpm," he says. "Coupled
with a U-joint that transfers power more
efficiently from the motor to the bit, this
helps the express BHA deliver higher
rates of penetration."
Every motor TDI deploys comes embedded with drilling dynamics sensors
from Sanvean Technologies, one of TDI's
business units, Woloshyn notes. He says
this is possible because the sensors can
be embedded in all TDI motors. Sensors
also can be embedded in bits and other
BHA components rather than utilizing
carrier subs.
"The sensors gather shock and vibration
data, which is critical for understanding
cyclical fatigue, as well as rpm and temperature. We can use the sensor information to pinpoint drilling dysfunctions such
as stick-slip and torsional oscillations to
see how they are affecting the bit and
BHA," Woloshyn says.
"After each run, we use proprietary
software to download and analyze the
drilling dynamic data so we can highlight
areas of concern and help the operator
improve performance on the next run,"
he says. "This process is efficient and
rapid enough to analyze the data before
the next section or well."
Hole Quality
Improving hole quality is one of the
most promising paths toward reducing
break-even costs, says John M. Clegg,
Weatherford fellow for drilling. "Smooth,
high-quality wellbores have both immediate and long-term benefits," he says.
"In the short term, they help control well
construction costs by reducing the chance
of getting stuck while drilling or running
casing or liners."
Once the well is on production, smooth
holes minimize wear and tear on rods
and electric submersible pumps, he continues, adding "Because laterals that porpoise up and down contain sumps where
water and sand can collect and hold back

liquids or gases, it's also likely that
straight laterals improve production. Early
evidence supports that theory."
With those benefits in mind, Clegg
says Weatherford has developed a pushthe-bit RSS with three independently
controlled pads that is designed to drill
the curve, then deliver a straight lateral.
"Independent control is the important
feature," Clegg says. "While the tool is
drilling the curve, we can open flow to
extend the pad on the opposite side of
the hole from the direction we want to
go. For example, if we are trying to build
angle, we would open the valve to the
piston on the low side of the hole to
extend the steering pad there and push
the bit upward.
"When the bit reaches the lateral and
needs to drill straight, we shut off pressure
to all three steering pads at the same
time. This eliminates the system's directional bias and allows the bit to drill
ahead as though the steering system were
no longer there," Clegg says.
By adjusting the independent pads,
the driller can fine-tune the bias from
zero to 100 percent in cycles of two
minutes or less, Clegg reports, noting
that these adjustments can be automated.
He says the precise control enables the
tool to drill a smooth curve whether the
operator wants a severe dog leg or a
gradual one.
"In the two years since we commer-

cialized the tool, we have drilled 550,000
feet, including many runs in U.S. plays
such as the Permian Basin and the Marcellus," Clegg says. "The tool has consistently drilled long lateral sections, tangent build sections and vertical sections
with extremely accurate control."
In many of the system's applications,
operators had trouble getting legacy tools
out of hole or running casing on previous
wells. "Every time the operator identified
that as a challenge, the RSS with independently controlled pads has passed
with flying colors," Clegg says. "Because
it delivers such smooth wellbores, we
have never had issues getting assemblies
down hole after runs."
According to Clegg, Weatherford's
RSS is affordable enough to compete
with mud motors. "We wanted to keep it
from being disqualified for cost, so we
made the design as simple and robust as
we could, which reduces the operating
cost," he says.
"We also looked for ways to increase
utilization, one of the biggest drivers of
RSS economics," Clegg adds. "Unlike
many traditional rotary steerable systems,
which need to be shipped to specialized
maintenance centers and often take a
week to repair, the new RSS can be repaired in any motor shop with a chest of
hand tools. In fact, during tests, we would
often fix one at the rig site and turn it
around in a few hours."

Coming In May
The Sooner State's oil and gas industry will get a closer look when the
May issue of The American Oil &
Gas Reporter offers an issues update
about the Petroleum Alliance of
Oklahoma. Learn about the subjects
occupying Oklahoma's oil and gas
companies in next month's AOGR.

With its three independently extendable pads, Weatherford's latest rotary steerable system offers precise control over the bit's path. The company says this lets drillers build a
curve with the desired severity, then retract all three pads to eliminate directional bias
and create a straight, smooth lateral.

APRIL 2020 65

American Oil and Gas Reporter - April 2020

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