American Oil and Gas Reporter - July 2015 - 89

SpecialReport: New Products/Technology
ations can resume while the logging engineer reviews data recorded.

FIGURE 2

Drill pipe Hang-off sub Portal bit

Telemetry, memory,
gamma ray tool

Density
tool

Total length: 63.7 feet
Caliper

Wired drop-off No-go collar
and retrieval tool

Batteries

Neutron
tool

Induction array
tool

The key components of the unique, through-the-bit deployment platform and small-diameter tool string are shown here.

were more expensive. However, when
they deployed the smaller diameter
through-the-bit tool string, they were able
to use less costly WBM without compromising evaluation quality.
After reducing drilling costs as much
as 15-20 percent in those early wells, the
operator initiated a horizontal drilling
campaign in the field. By computing rock
and fracture properties, petrotechnical
professionals were able to identify optimal
zones for hydraulic stimulation and design
custom, engineered completions-rather
than blind geometric stages-for every
lateral in the field. In July 2014, the company reported that advanced drilling technology and engineered completions had
effectively reduced drilling times by 20
percent, and average drilling and completion costs by 40 percent, while increasing 90-day cumulative production
by an astounding 85 percent.
Some 3,000 logging jobs across North
America have used through-the-bit logging
to date; about 75 percent of those were
in horizontal wells. Key components of
the deployment platform include a portal
pass-through PDC bit, the slim logging
tool string with a no-go collar, a hangoff sub assembly, and a wired drop-off
and retrieval tool (Figure 2).
Following is a typical logging sequence
as illustrated in Figure 1:
* First, drillers use the portal bit to
ream to TD, conditioning the borehole
for logging.
* Next, drillers pull the bit off bottom
to provide sufficient room for the tool
string, configured either with individual
tools or as a triple- or quad-combo.
* Where gravity descent is not possible, engineers pump the logging tool
string down through the drill pipe, through
a 21⁄2-inch portal in the bit, and into the
open borehole. Once logging sensors are
deployed, a hang-off sub just above the

bit prevents the tool string from extending
farther down by capturing a no-go collar
near the top of the tool string.
* Once logging engineers verify operational functionality, they disconnect
the wired drop-off tool from the tool
string and remove the wireline from the
drill pipe.
* As drillers trip the pipe out of hole,
the tool string logs the open-hole section
in memory mode.
* Once the logging tool string has
reached the casing shoe, drillers pull the
portal bit and tool string up into the casing.
* Then logging engineers lower the
wired retrieval tool through the drill pipe,
latch onto the tool string, return it to the
surface, and recover it from the drill pipe,
without having to bring the rest of the
pipe and bit out of the hole.
At this point, drilling and other oper-

System Benefits
This unique deployment and retrieval
system offers operators a number of important benefits in challenging horizontal
boreholes. For one thing, combining the
logging run with a conditioning trip reduces the usual rig time-and costs-required to acquire log data. By not deploying the tool string until the bit has
reached TD, logging tools undergo considerably less exposure to potentially
damaging shocks, vibration, and high
temperatures. Using a wireline drop-off
and retrieval tool means operators recover
the logging tool string faster, with lower
risk.
If, for example, hole conditions deteriorate and the drill pipe becomes stuck
while tripping out, the operator still can
retrieve critical log data while avoiding
the possibility of leaving radioactive
sources in the hole. Finally, the system
is extremely driller-friendly. Throughout
deployment and logging operations, drillers
maintain complete control of the drill
string, circulating and rotating as needed,
without any fear of damaging the tool
string.
There are, of course, other ways to
deploy through-the-bit logging tools. One
alternative, for example, would be to rig
the tool string inside a drill collar at the
surface, run it into the hole, pump it out
through the bit, and log in memory mode

FIGURE 3
Perforation Efficiency
82%
Engineered
Completion
Eagle Ford
Consortium
6 Well Avg

95%
90%

88.8%

80%
75%

85.3%

83.8%

85%

78.8%

78.5%
75.3%

70%
63.8%

65%
60%
55%

64%
Geometric
Completion
Eagle Ford
17 Well Avg

50%
Engineered

17 Wells
Eagle Ford Geometric

Perforation efficiencies for engineered completions averaged 82 percent-an 18 percent
increase over geometric completions-with a 50 percent reduction in nonperforming clusters. Net present value calculations showed an increase of 40,000 barrels-worth $1.5
million-in the first year of production.

JULY 2015 89

American Oil and Gas Reporter - July 2015

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