ENVIRONMENTAL ASSESSMENT

Executive Summary

by






and

S.L. Ross Environmental Research Ltd.
Coastal Ocean Associates
for
Canada/Nova Scotia Offshore Petroleum Board
and
Mobil Oil Canada Properties (Proj. Mgr)
Shell Canada Ltd.
Imperial Oil Resources Ltd.

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Gulf Canada Resources Ltd.
Chevron Canada Resources
PanCanadian Petroleum Ltd.
Murphy Oil Company Ltd.
Norsk Hydro Canada Oil and Gas Inc.

LGL Report No. TA 2281

August 2000

ENVIRONMENTAL ASSESSMENT OF
EXPLORATION DRILLING OFF
NOVA SCOTIA

EXECUTIVE SUMMARY

by

Denis H. Thomson, Rolph A. Davis, Randy Belore1, Elizabeth Gonzalez2,
John Christian, Valerie Moulton and Ross E. Harris

LGL Limited
environmental research associates

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P.O. Box 280, 22 Fisher Street
King City, ON
L7B 1A6

1S.L. Ross Environmental Research Ltd.
Ottawa, Ontario

2Coastal Ocean Associates
Halifax, Nova Scotia

for

Canada/Nova Scotia Offshore Petroleum Board

and

Mobil Oil Canada Properties (Proj. Mgr)
Suite 1000, 1701 Hollis Street
Halifax, N.S. B3J 3M8
Shell Canada Ltd.
Imperial Oil Resources Ltd.
Gulf Canada Resources Ltd.
Chevron Canada Resources

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PanCanadian Petroleum Ltd.
Murphy Oil Company Ltd.
Norsk Hydro Canada Oil & Gas Inc.

LGL Report No. TA 2281
DRAFT

August 2000
PROJECT SPONSORS

This project was conceived and funded by the following oil companies and the personnel
listed.

Mobil Oil Canada Properties
330 - 5th Avenue S.W.
Calgary, Alberta T2P 2J7

Mr. Robert Kerr
Manager, Environment, Health & Safety
Suite 1000, 1701 Hollis St.
Halifax, NS B3J 3M8

Mr. Gene Skeith, Geophysical Advisor
Mr. Scott Brown

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330 - 5th Avenue S.W.
Calgary, Alberta T2P 2J7

Dr. Philip T.P. Tsui
Manager - Corporate Environmental
Health and Safety Policy and Issues
Mobil Corporation
3225 Gallows Road
Fairfax, VA 220037-0001

Shell Canada Limited
400 - 4th Avenue S.W.
P.O. Box 100, Station M
Calgary, Alberta T2P 2H5

Norm Wiens, P.Geoph.
Manager, East Coast Offshore Exploration

Les Groeller
Senior Drilling Foreman

Dr. Douglas A. Mead
Senior Environmental Scientist

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Imperial Oil Limited
237 Fourth Avenue S.W.
P.O. Box 2480, Station M
Calgary, Alberta T2P 3M9

Erna Baets.


PanCanadian Petroleum Ltd.
East Coast Operations
Suite 700, Founders Square
1701 Hollis Street
Halifax, Nova Scotia B3J 3M8

Mr. R.S. (Scott) Little
Loss Control Manager

Chevron Canada Resources
500-Fifth Avenue S.W.
Calgary, Alberta T2P 0L7

Mr. P.C. (Phil) Milford

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Team Leader, Nova Scotia

Gulf Canada Resources Ltd.
401-9th Avenue S.W.
P.O. Box 130 Station M
Calgary, Alberta T2P 2H7

Mr. Martin Dashwood

Murphy Oil Company Ltd.
#2100, 555-4th Avenue S.W.
P.O. Box 2721
Calgary, Alberta T2P 3Y3


Norsk Hydro Canada Oil and Gas Inc.
#1190, 111-5th Avenue S.W.
Calgary, Alberta T2P 3Y6




TABLE OF CONTENTS

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TABLE OF CONTENTS *
INTRODUCTION *
PROJECT DESCRIPTION - Exploration Drilling *
IMPACT ASSESSMENT METHODOLOGY *
Valued Ecosystem Components (VECs) *
Impact Definitions *
Magnitude of Impacts *
Scale of Impacts *
Duration of Impacts *
Likelihood of Occurrence *
Significance of Potential Impacts *
Public Consultation *
LEVEL 1 INTERACTION MATRIX *
IMPACTS OF ACTIVITIES *
Cumulative Impacts *
Cumulative Impacts of the Project *
Noise and Disturbance *
Operational Discharges of Oil *
Influence on the Benthos *
Garbage and Waste Materials *
Accidental Spills of Oil *
MITIGATION AND MONITORING *
Routine Discharges *

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Project Specific Mitigation Measures *
Accidental Spills of Condensate *
Spill Response *
Contingency Plans *
Monitoring *
Environmental Protection Plan *
APPLICABILITY OF THE GENERIC EA *
LITERATURE CITED *


INTRODUCTION
Several hydrocarbon exploration wells are planned to be drilled offshore on the Scotian
Shelf in the next few years. Before granting approvals to drill, the Canada/Nova Scotia
Offshore Petroleum Board (CNSOPB) must evaluate the potential environmental effects
of each well. Similarly, the Canada/Newfoundland Offshore Petroleum Board (CNOPB)
must approve wells on the St. Pierre Bank off southern Newfoundland. Given that many
technical aspects of offshore exploration drilling are common to all wells, it is
appropriate to conduct a generic assessment of the common aspects of all offshore
exploration wells. Thus, drilling applications for specific wells would only need to
address those aspects that were unique to that well or site.

This generic assessment applies to year-round drilling operations. It will be effective for a
five-year period beginning with drilling in mid 2000. It is anticipated that the generic
assessment will be updated after five years to reflect new information about the receiving
environment, new drilling technologies, and new information on the effects of drilling on
the environment.

PROJECT DESCRIPTION - Exploration Drilling
Geophysical (seismic) and other types of surveys are used to determine the location and
extent of possible oil or gas bearing geological formations. Oil and gas are not present as

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large pools located within holes in rock. They are located within porous rock. These
porous formations may contain hydrocarbon deposits that are large enough to be
developed or they may contain water or only small quantities of hydrocarbons.
Exploration drilling is the only sure way to confirm whether hydrocarbons are present
and what kind of hydrocarbons are present (gas, oil). Experience in the study area
indicates that prospects could contain formation oil, gas, condensate or water or a
combination of any of these. There are many kinds of crude oil. Some is thick as tar and
some is as light as home heating oil. Condensate is neither crude oil nor condensed gas. It
is a very light hydrocarbon resembling gasoline.

Typically, the drilling of a single exploration well in the study area requires from 50 to
100 days depending on the complexity of the well (i.e. rock and reservoir properties),
weather, and the depth of the well. In the event that hydrocarbons are found during
exploration drilling, testing may be required to further define a prospectís potential for
development. Testing a well may include several types of activities and usually requires
about 10 - 40 days. Testing within the study area, typically may involve between 1 and 8
individual well tests of different reservoirs traversed by the well. Flow rates and the result
of other tests give some indication about whether hydrocarbons may be present in
quantities that are economical to develop. Once the presence of hydrocarbons is
confirmed by exploratory drilling and associated testing, further appraisal or delineation
drilling may be required. The geologists use their survey results to estimate the location
and size of hydrocarbon-bearing formations. Delineation wells are then drilled to
determine the actual size of a formation and to estimate how much oil may be present.

Drilling exploration wells in offshore areas requires the use of mobile offshore drilling
units (MODUs). Types of MODUs include jack-up rigs, semi-submersible rigs, and drill
ships. The type of drilling rig used for exploration drilling is determined by water depth.
The water depths in the study area range from 10 m to 4000 m.

Drilling rigs need to be supplied with drilling equipment, fuel, food and a myriad of other
materials to maintain a crew, vessel and drilling operations. In addition, there are regular
crew changes and visitors that need to be carried to and from the platform.

While drilling the hole, a drill bit grinds rock into small pieces called cuttings. If cuttings
were left in the hole the drill bit could not turn. Fluids called drilling muds are needed to
move the cuttings away from the drill bit and out of the well. It is expected that the
significant majority of exploration wells and the majority of footage drilled covered by
this assessment will be carried out using water-based drilling muds. In certain situations,

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