American Oil and Gas Reporter - January 2020 - 76

Tech Trends
bore, leading the operator to suspect that
the wellbore was drifting from its planned
path. Because of the missing and invalid
MWD surveys, the operator required a
solution that would allow the well to be
resurveyed while minimizing the amount
of associated downtime.
The new solid-state gyro surveying
system was run in a single trip in combination with third-party cement bond logging and casing collar locator tools on
wireline while logging out of the hole.
The system was run without using any
additional rig time while logging from a
total depth of 25,634 feet. The operator

was able to take high-accuracy, highspeed surveys every 32 seconds.
After running the gyro, improvements
were made in several areas. First, the
EOU was reduced by 65% versus conventional MWD surveys with IFR, BHA
sag, and MSA corrections, dramatically
improving survey accuracy and precision
(Figure 1).
Making this correction, the well's bottom-hole location laterally moved 210
feet and identified a declination error of
0.92, which proved that there was more
drillable space for future wells (thus more
recoverable reserves) than estimated. Sec-

FIGURE 1
EOU Comparison in Utica Shale Well (Solid-State Gyro versus MWD)
0
-2,000

MWD+IFR+SAG+MSA
Solid-State Gyro

North (ft)

-4,000
-6,000
-8,000
-10,000
-12,000
-2,000

2,000

4,000

6,000

8,000

10,000 12,000

East (ft)

-10,000
65%
EOU
Reduction

-10,500
-11,000
-11,500
-12,000

210-ft
Correction

76 THE AMERICAN OIL & GAS REPORTER

00
0
-1
0,
50
0
-1
1,
00
0

-1
0,

,5
00
-9

00
-9
,

-8
,

-12,500

ond, by running the new system to TD
during the well's planned logging run,
the operator saved 36 hours of rig time
that would have been required to replace
the failed MWD tool.
Accurate Lateral Placement
In the Permian Basin, an operator was
looking for a way to improve the cost efficiency of his post-drilling surveys. Traditionally, a post-drilling survey in the
lateral would require a host of on-site
equipment, including pumping and wireline trucks, as well as a minimum of 12
hours of dedicated rig time to run an
electric-line gyro. By incorporating a
drop survey landing in the BHA and
using the rig's circulating time as the
pump-down regime, the operator aimed
to save rig time while also reducing the
risk of stuck pipe.
The solid-state gyro provided a drop
multishot survey in the well's lateral
section while tripping out of hole, with
the system pumped into the well during
the rig's standard circulating time. It
did not require a nonmagnetic collar,
which would have increased the cost
of the BHA, and its dual-probe configuration provided data redundancy and
higher accuracy. By confirming that an
agitator was not in the drill string, the
gyro was able to add a landing point
directly into the BHA significantly
closer to the bit, thereby increasing the
survey's effectiveness.
Using the drop survey method saved
the operator 15 hours of rig time. Although using this survey method previously was impossible in the lateral hole
section, implementing the solid-state
gyroscopic technology eliminated the
inclination restraints of traditional surveying equipment. The operation used
the time the rig was circulating fluid to
clean out the wellbore, with this regime
able to effectively pump the equipment
through the lateral to the landing point.
In addition to saving $28,000 in rig
time and additional third-party services,

American Oil and Gas Reporter - January 2020

Table of Contents for the Digital Edition of American Oil and Gas Reporter - January 2020