American Oil and Gas Reporter - November 2016 - 60

SpecialReport: MWD/LWD Technology
the 15-foot-thick target zone was at 9,334
feet TVD. The well plan projected in the
geosteering model showed the trajectory
landing at three feet TVD below the top
with 89 degrees inclination, while formation dip was believed to be flat. Figure
3 shows the preliminary model before
landing.
Geosteering began at 9,417 feet MD

(8,990 feet TVD). The correlation was
good in terms of expected log responses,
but the formation was shallower than expected. At 500 feet MD before landing,
the target was raised 10 feet TVD after
the formation tops consistently came in
shallower than predicted, leading to a
higher probability that the reservoir also
would be shallower.

FIGURE 6
Final Updated Geosteering Model for Columbo Well
00.00 360
1.00

0
-10
1,000
100
10

1,000
100
10

100
0
8,060

TVD (ft)

8,080
8,100
8,120
9,200

9,400

9,600

JOHN CHAKALIS is a geophysical
adviser at Energy XXI. His primary role
is interpreting seismic data to identify
drilling prospects in various fields.
Chakalis has supervised the geosteering
of multiple wells in the West Delta 73
Field, providing seismic and log analysis
support. Before joining Energy XXI, he
worked as a geophysicist in the deepwater
Gulf of Mexico for Hess Corporation
and Devon Energy. Chakalis holds a
B.S. in geophysics from the Colorado
School of Mines and an M.S. in geophysics from the University of Houston.
ANDY SIMS is a senior reservoir
engineer at Energy XXI, and is primarily
responsible for conducting the technical
and economic analysis of development
projects on the Gulf of Mexico Shelf.
His primary focus in the West Delta 73
project was to evaluate horizontal development wells and their associated
reserves. Before becoming a reservoir
engineer, Sims was a production engineer
for Energy XXI. He holds a B.S. in petroleum engineering from Texas A&M
University.
60 THE AMERICAN OIL & GAS REPORTER

MD (ft)

9,800

10,000

10,200

SHAIKH AAMIR IQBAL is a senior
technical adviser, MWD/LWD, and
geosteering domain expert for Halliburton
Sperry Drilling in the Gulf of Mexico.
His areas of expertise include petrophysics,
geosteering, operations geology, and
MWD/LWD. Iqbal began his career in
the Middle East, working in Saudi Arabia,
Kuwait, Oman and Pakistan before moving
to North America in 2011. He previously
worked for British Petroleum, Orient Petroleum, and Baker Hughes. Iqbal holds
a B.S. and an M.S. in geology from University of Karachi in Pakistan, and is
pursuing an M.S. in petroleum geology
from the University of Houston.
PAVEL MARTINEZ works as a
geosteering geologist for Halliburton
Sperry Drilling. He previously served as
a geosteering technical adviser in Kuwait.
Martinez joined Halliburton in 2001 and
held various positions in Colombia, including real-time operations and MWD
with a focus on geosteering operations.
He began his career as a well-site geologist
with Geopozos in Colombia. Martinez
holds a B.S. in geology.

The effective option was to hold at an
87-degree inclination until the top was
confirmed with at-bit gamma ray. The
H35 sand top was logged at 9,319 feet
TVD, or 15 feet higher than expected,
and drilling operations continued until
resistivity verified the target top. The
well was then landed for a casing point
at 10,463 feet MD (9,322 feet TVD), or
three feet TVD below the target top, and
avoided drilling more footage in the H35
sand.
The geosteering model was refined
during the casing break, including updating
the trajectory. The thickness of the target
zone remained as expected for the prelateral forward model, but because the top
was encountered at a higher TVD, a distance of seven feet TVD below the H35
top was determined to be the optimal
placement to enable greater flexibility
toward the toe of the well.
The horizontal section of the Hawkeye
well began at the seven-inch casing shoe
in the target zone. Drilling out of the
casing, the measured average resistivity
was not as expected, based on offset well
data. Analysis determined the difference
was related to a lateral variation in formation quality. The density log verified
this interpretation.
As drilling continued, the quality of
the sand improved. The correlations and
tool responses after beginning drilling
enabled local formation dip to be estimated
at -0.5 degrees, which appeared opposite
of the expected scenario. Local variations
were observed and the trajectory remained
between 9,326 and 9,330 feet TVD.
Closer to total depth, the formation
started dipping from -1.0 to -4.5 degrees
in a short section, causing the wellbore
to exit the H35 sand into the shale above.
Dropping inclination at the end of the
lateral section was not a viable option
because of the proximity of the OWC.
The sand top was logged at 9,327 feet
TVD, eight feet deeper than the top intersection at landing. TD occurred at
11,237 feet after drilling 774 feet with
88 percent total in-zone footage. Figure
4 shows the updated final model.
Columbo Well
The Columbo well targeted the F35
sand. Resistivity, density and gamma ray
logs from multiple offset wells were included in the model as a reference. Stratigraphic cross-sections showed lateral
variations within the surrounding wells.
Based on correlations, a transitional

American Oil and Gas Reporter - November 2016

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