UNCONVENTIONAL DRILLING
Chesapeake drills U-turn lateral
to optimize tight lease space
Horseshoe-shaped well was drilled in South
Texas using conventional directional assembly
BY JESSICA WHITESIDE, CONTRIBUTOR
Drilling longer horizontal wells has
become a common strategy for extend-
ing exposure to promising reservoirs,
benefiting well economics by increasing
production potential. However, tight lease
boundaries can limit the feasibility of this
strategy in some areas. After all, how can
you drill a 10,000-ft lateral in a lease that’s
only 5,000-ft wide?
Chesapeake Energy has adopted a way
to circumvent such space constraints by
drilling a “U-turn” horizontal well. The
initial lateral makes a 180° turn to create
a second lateral parallel to the first in the
same formation. The resulting horseshoe
shape effectively doubles the lateral length
possible within the lease from a single
vertical section. Chesapeake developed its
first U-turn well in 2020 on a lease in the
Eagle Ford Shale in South Texas. The expe-
rience was presented at the 2022 IADC/
SPE International Drilling Conference in
Galveston, Texas, on 10 March.
Joe Kiefner, Chesapeake’s Category
Manager – Completions & Sand, said the
U-turn well met production expectations –
within a few percentage points of the com-
pany’s type curve for the area – and saved
money, helping the company to make the
most out of a small lease space in a matur-
ing legacy field.
Calling the project highly successful,
Mr Kiefner said Chesapeake has added
U-turns to its portfolio of wells and identi-
fied 20 to 30 more potential U-turn loca-
tions. The company has executed on
a couple of those wells and is bullish
about the ability of this approach to opti-
mize tight leases where drilling the ideal
straight long lateral is not possible.
“We feel like this is not something that
we should just keep internal. This is some-
thing that is better for the industry, and I
think is better for our ability to utilize the
space that we have,” Mr Kiefner said.
Chesapeake is not the only company to
try the U-turn approach. Shell successfully
drilled a horseshoe well in the Permian
Basin in 2019 using a rotary steerable
system. Chesapeake bills its 2020 U-turn
well as the first such application in South
Texas and the first using a fully conven-
tional directional assembly, rather than a
rotary steerable system.
Selecting the trajectory
Chesapeake tested the U-turn lateral
strategy with its service providers as a
potential tool to improve well economics
and options within highly developed acre-
age blocks in the Eagle Ford Shale.
The test site was a 5,000-ft-wide lease
that contained an existing producing well.
The U-turn maneuver on the new well
resulted in a completed lateral length of
9,200 ft (4,900 ft of treatable lateral in one
arm of the U and 4,300 ft in the other).
According to Chesapeake, this trajectory
significantly improved well economics by
“utilizing a horizontal turn as a hydrocar-
bon pathway, rather than an additional
vertical section from a new well to gain
the equivalent treatable lateral length.”
The measurement of treatable length
does not include the U-turn portion of
the well. To maximize the in-unit foot-
age available for the lateral length, the
company drilled the curve section into the
adjacent unit and did not frac that sec-
tion. Shell reportedly also elected to omit
curve stimulation on its 2019 horseshoe
well. Chesapeake’s case study report noted
that to frac the curve would be “capitally
inefficient due to the turn portion of the
lateral being drilled in the direction of
maximum horizontal stress, which would
not optimally grow hydraulic fractures
perpendicular to the wellbore.”
Planning pays off
In some cultures, the horseshoe is a
symbol of good luck, but developing the
horseshoe-shaped well on Chesapeake’s
Eagle Ford lease took more than just luck;
it took lengthy planning, modeling and
simulations before drilling began. That
was followed by real-time updating of fac-
tors such as torque and drag (updated at
1,000-ft intervals).
Cumulative degrees and Directional
Drilling Index (DDI) values were among the
key elements considered during planning
and monitoring to understand the tortuos-
ity associated with the U-shaped path.
The team’s DDI assessment found many
successfully drilled and completed wells
with complex trajectories that had higher
DDI values than what was expected for the
U-turn, increasing confidence in their abil-
ity to execute the unusual path.
“If it doesn’t work on paper, it’s probably
not going to work in real life. But all of
our models from the drilling and comple-
tions standpoint showed that it worked on
paper. It was just on us to go execute,” Mr
Kiefner said.
The team used Chesapeake’s histori-
cal base model for the area to guide its
expectations for the well and applied the
company’s standard best practices to miti-
gate risks. Their due diligence included
drafting contingency plans for various
scenarios, including developing a back-
up option to continue development if the
U-turn failed.
“At any point, if things went sideways,
we could have stopped that plan and cased
out a single 5,000-ft lateral and just drilled
another vertical section,” Mr Kiefner said.
“We had planned for that contingency and
permitted it as such.”
Adjusting in real time
Fortunately, they didn’t need to acti-
vate that fallback option as the U-turn
project went almost entirely according
to plan, despite some on-the-fly adjust-
ments required to motor and mud weights.
Surprisingly, the added tortuosity of the
U-turn did not have a very large impact
on operations, said Riley Schultz, Drilling
Engineer for Chesapeake.
D R I L L I N G C O N T R AC T O R • M AY/J U N E 202 2
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