Anticosti Island 2-D seismic line, illustrating new Hydrothermal
Dolomite (HTD) interpretation. (Click on image to enlarge)
interpretation courtesy of Corridor Resources
Canada, this play is all about the rocks.
refer to it as "HTD," or hydrothermal dolomite. Others call it thermobaric
or zebra dolomite.
Morin, a senior petroleum geologist with Hydro-Québec, uses the
French terms "dolomite hydrothermale" and "dolomite baroque" to
describe its ribbon-like fabric.
the descriptor, this rock is characterized by coarsely crystalline,
high temperature saddle dolomite and forms the prolific reservoir
trends of the Trenton-Black River that stretch across continental
North America. The Trenton-Black River fairway -- containing the
world class Albion-Scipio and Lima-Indiana oil fields -- crosses
into Canada where it is virtually unexplored to date.
an AAPG member, is part of Hydro-Québec's recently formed oil and
gas division, Hydro-Québec Pétrole et Gaz. Two years ago, Hydro-Québec
-- North America's giant in hydroelectricity generation -- entered
the oil and gas exploration game with a commitment to invest $C
330 million by 2010.
mandate is to explore for oil and natural gas in Eastern Québec
-- namely the Gaspé Peninsula and the Gulf of St. Lawrence.
by a new understanding of the mechanisms that create hydrothermal
dolomites -- and the critical role that wrench faults play as conduits
for high pressure, high temperature dolomitizing fluids -- Morin
is re-evaluating geological and geophysical data bases for Trenton-Black
River potential in the Appalachian front of Eastern Canada.
for an Albion-Scipio look-alike that could be lurking, undetected,
in his own backyard.
keying off the historical natural gas production from Ordovician
age carbonates in the St. Lawrence Lowlands in southern Québec (close
to the New York state border) and recent oil production tests from
Ordovician age dolomite reservoirs on the Port au Port Peninsula
in Western Newfoundland.
these two endpoints -- nestled in the Gulf of St. Lawrence -- is
in Western Newfoundland at the Port au Port Peninsula, unequivocally
demonstrate that the oil system works well east of the Anticosti
platform," Morin said
Island is remote, accessible only by ferry for oil and gas field
operations. Approximately 8,000 square kilometers in size, the island
is home to 300 people and 200,000 white-tailed deer.
is situated in a favorable structural position, on an inflection
point -- or a transform zone -- at the leading edge of the Appalachian
thrust front. The island is bisected by the Jupiter Fault Zone,
a right lateral, strike-slip feature similar to the Bowling Green
Fault Zone of the Lima-Indiana Field that has 500 million barrels
of oil and 2 tcf of gas.
the late 1990s, Shell Canada and Encal Energy (now Calpine Corp.)
farmed into Halifax-based Corridor Resources' acreage position,
acquiring 400 kilometers of 2-D seismic data and an aeromagnetic
Shell followed up by drilling five wells over a two-year period
from 1998-99; the wells were abandoned, but provided useful data
points for calibration. Shell and Calpine relinquished their holdings
on Anticosti in late 2002.
Resources operates eight exploration licenses on the south and central
part of Anticosti, totaling just over 400,000 acres. Through a partnership
with Hydro-Québec, Corridor has varying interests in an additional
1.1 million acres of exploration land in the northern and southern
part of the island; the land comprises 19 leases and five permits
with mixed operatorship.
Tom Martel, Corridor's chief geologist, described his company's
recent shift in exploration thinking at Anticosti:
including us, had been looking for the Romaine formation (the Lower
Ordovician, Beekmantown equivalent that produced gas on the Quebec
mainland)," he said. "It wasn't until we drilled our third well,
Chaloupe #1, that we realized the Middle Ordovician Trenton-Black
River formation might be prospective."
Chaloupe #1 they lost 3,000 barrels per day of mud into the Trenton-Black
River formation. The well encountered 70 meters of porosity and
fractures in the Trenton-Black River and Romaine formations. Methane
shows were recorded while drilling through the Romaine formation.
to Martel, only two wells on Anticosti can be considered adequate
tests of the Trenton-Black River, which occurs at depths between
800 to 2,000 meters.
cores, the Geological Survey of Canada completed fluid inclusion
studies in the Chaloupe #1 well, demonstrating several episodes
of high temperature, hydrothermal dolomitization in the Trenton-Black
River and Romaine formations.
drilled near the Jupiter Fault Zone (JFZ) show thick hydrocarbon
columns, according to Martel. Examination of the chip samples from
Chaloupe #1 indicates 41 degree API live oil.
#1 well was drilled in 1963 adjacent to the JFZ. The well contained
HTD with live oil-filled vugs, and was highly fractured in the Trenton-Black
River and underlying Romaine formations -- while drilling through
the Trenton-Black River and Romaine formations with a continuous
coring rig, the operator lost 28,000 barrels of fresh water into
can't over-emphasize the importance of the seven-kilometer-wide
JFZ to the future success of the HTD play. The aeromagnetic survey,
he said, illustrates different types of basement rock straddling
the JFZ, suggesting significant strike-slip movement.
seismic interpretation, Martel believes that the JFZ was active
during the Middle Ordovician. He describes how the trans-tensional
movement on the strike-slip fault results in a void or space, creating
the mechanism to "suck up the hydrothermal fluids in a very rapid
Martel said, "works like a pump, creating a vacuum."
It's a New
"newcomer" Hydro-Québec shipped five vibrator trucks to Anticosti
for the acquisition of a $C 4.8 million, 325-kilometer 2-D seismic
to Morin, infrastructure for roads is "mostly non-existent."
where the vibroseis trucks couldn't go cross-country, a dynamite
source was used for seismic data acquisition. Just under half of
the program was acquired with dynamite source.
also acquired a magneto-telluric survey to assist in identifying
faulting, karsting and voids -- telltale features that point to
the existence of hydrothermal dolomite rocks in the subsurface.
classic collapse features like the Albion-Scipio Field," Morin said
of his geophysical interpretation. "We're very excited -- it's a
new game ... We have a lot of examples (analogs) of how this play
and Hydro-Québec -- jointly and separately -- plan to drill three
wells this summer, back-to-back, thus sharing the costs of mobilizing
a rig to Anticosti. The drilling program will target the JFZ, testing
a related sag feature with a seismic dim zone characteristic of
#1 well also will be redrilled, this time targeting the Trenton-Black