
1Johnston,
Carey
A.,
"
EPA
Data
Needs
to
Help
EPA
Assess
section
316(
b)
Comments
related
to
MODUs,"
Memorandum
to
Alan
Spackman
(
IADC)
et
al.,
March
21,
2001.

Page
1
of
4
Memorandum
From:
Carey
A.
Johnston
USEPA/
OW/
OST
ph:
(
202)
260
7186
johnston.
carey@
epa.
gov
To:
File
Cc:
Mr.
James
M.
Magill
U.
S.
Coast
Guard
Vessel
and
Facility
Operating
Standards
Division
Date:
May
7,
2001
Re:
Notes
from
April
4,
2001
Meeting
with
U.
S.
Coast
Guard
Background
EPA
received
several
comments
on
the
August
10,
2000
new
source
cooling
water
intake
proposal
related
to
mobile
offshore
drilling
units
(
MODUs).
EPA
outlined
the
major
issues
raised
by
the
offshore
oil
and
gas
industry
and
identified
several
data
needs.
1
EPA
contacted
Jim
Magill
(
202­
267­
1082;
jmagill@
comdt.
uscg.
mil)
U.
S.
Coast
Guard,
to
assist
with
EPA's
data
collection.
Mr.
Magill
is
an
Offshore
Specialist
in
the
Coast
Guard's
Vessel
and
Facility
Operating
Standards
Division.
On
April
4,
2001,
Peter
Sherman
(
EPA
Contractor,
TetraTech)
and
I
met
with
Mr.
Magill
at
his
Coast
Guard
Headquarters
office.
The
meeting
lasted
approximately
90
minutes.
The
following
are
the
Mr.
Magill's
answers
to
my
questions.

Summary
Meeting
Notes
Q:
What
are
typical
cooling
water
intake
(
CWI)
rates,
velocities,
and
durations?

Mr.
Magill
reviewed
and
agreed
with
the
cooling
water
intake
figures
provided
in
comments
to
the
proposed
rule
by
Mr.
Spackman
(
International
Association
of
Drilling
Contractors).
Mr.
Magill
noted
that
Mr.
Spackman
formerly
worked
for
the
U.
S.
Coast
Guard
and
should
have
a
sufficient
background
to
estimate
these
CWI
rates.
Specifically,
Mr.
Spackman
identified
the
following
CWI
rates
for
the
following
vessels:
Page
2
of
4
S
Drill
Ships
16
­
20
MGD;

S
Semi­
submersibles
2
­
15+
MGD;

S
Jack­
ups
2
­
10+
MGD;

S
Submersibles
2
­
10+
MGD
w/
most
<
2
MGD;
and
S
Drill
Barges
<
2
MGD.

Mr.
Magill
also
agreed
with
Mr.
Spackman
that
the
majority
of
offshore
oil
and
gas
drilling
operations
use
drill
ships,
semi­
submersibles,
and
jack­
ups
with
submersibles
and
drill
barges
being
used
less
frequently
and
in
shallower
waters.
There
are
about
7
to
10
drillships
in
operation
in
the
GOM
with
the
remaining
bulk
of
drilling
being
split
50/
50
by
semi­
submersibles
and
jack­
ups.
Mr.
Magill
has
less
experience
estimating
through­
screen
cooling
water
intake
velocities
but
felt
that
Mr.
Spackman's
estimates
of
through­
screen
cooling
water
intake
velocities
for
each
of
the
MODUs
were
reasonable.

Mr.
Magill
stated
that
exploratory
drilling
can
take
1
to
3
months
while
development
drilling
can
take
1
to
2
years
to
drill
approximately
24
total
wells
for
a
particular
location.
Mr.
Magill
also
stated
that
the
life
span
of
semi­
submersibles
is
approximately
20
years.

Q:
What
are
the
potential
retro­
fit
costs
associated
with
reducing
the
intake
velocities
for
various
MODUs?

Mr.
Magill
stated
that
he
did
not
have
a
good
estimate
of
these
costs
but
did
have
a
general
idea
of
the
work
requirements
for
these
potential
retrofits.
Mr.
Magill
stated
that
retrofits
for
drill
ships
and
semi­
submersibles
that
use
seachests
as
the
CWI
structure
would
be
in
the
millions
of
dollars
(
8­
10)
and
require
several
weeks
to
months
for
drydocking
operations.
Complicating
matters
is
that
there
are
only
a
few
deepwater
drydock
harbors
capable
of
handling
semi­
submersibles.

Costs
for
retro­
fitting
jack­
ups
would
likely
be
much
less
complicated
and
expensive
than
sea
chest
retro­
fits.
Mr.
Magill
assumed
that
operators
could
install
a
bell
or
cone
intake
device
on
the
existing
CWI
structures
to
reduce
CWI
velocities.

Q:
What
is
a
typical
design
of
a
drill
ship
and
semi­
submersible
sea
chest?

Mr.
Magill
stated
that
in
previous
years
the
Coast
Guard's
Marine
Safety
Center
(
MSC)
reviewed
all
MODU
designs.
Now
that
function
has
been
delegated
to
the
American
Bureau
of
Shipping
(
ABS)
which
offers
a
wide
range
of
ship
classification
and
industrial
certification
services.
As
a
result
of
this
delegation,
Mr.
Magill
nor
the
MSC
had
any
sea
chest
designs
or
schematics
for
EPA
to
review.
In
general
there
are
three
pipes
for
each
sea
chest
(
these
include
CWIs
and
fire
pumps).
One
of
the
three
intake
pipes
is
always
set
aside
for
use
solely
for
emergency
fire
fighting
operations.
These
pipes
are
usually
back
on
the
flush
line
of
the
sea
chest.
The
sea
chest
is
cavity
in
the
hull
or
pontoon
of
the
MODU
and
is
exposed
to
the
ocean
with
a
screen
often
set
along
the
flush
line
of
the
sea
chest.
There
are
generally
two
sea
chests
for
each
Page
3
of
4
drill
ship
or
semi­
submersible
(
port
and
starboard)
for
redundancy
and
ship
stability
considerations.
In
general,
only
one
seachest
is
required
at
any
given
time
for
drilling
operations.

Q:
What
is
the
typical
depth
below
water
of
sea
chests?

When
semi­
submersibles
are
drilling
their
sea
chests
are
80
to
100
feet
below
the
water
surface
and
are
less
than
20
feet
below
water
when
the
pontoons
are
raised
for
transit
or
screen
cleaning
operations.
Drill
ships
have
their
sea
chests
on
the
bottom
of
their
hulls
and
are
typically
20
to
40
feet
below
water
at
all
times.

Q:
Must
CWI
velocities
be
higher
than
2­
5
ft/
s
to
reduce
marine
biofouling?

Mr.
Magill
stated
that
the
answer
depends
on
the
environment
in
which
you
are
drilling
and
gave
several
examples
from
his
field
experience.
His
experience
in
waters
off
of
the
Carribean
nation
of
Belize
show
that
there
can
be
substantial
biological
growth
on
vessel
structures
in
less
than
a
year.
Mr.
Magill
stated
that
current
Coast
Guard
requirements
are
that
operators
must
inspect
sea
chests
twice
in
five
years
with
at
least
one
cleaning.
These
requirements
are
particularly
important
to
ensure
that
the
separate
intake
for
the
fire
pump
is
clear.
Mr.
Magill
estimated
that
the
regular
cleaning
and
inspection
schedule
should
be
enough
to
control
marine
biofouling
in
the
GOM.

Q:
What
are
the
typical
water
requirements
for
various
MODU
operations?

Mr.
Magill
estimated
that
80%
of
the
intake
water
is
for
cooling
water.
Other
water
intakes
are
for
fire
pumps
(
intermittent),
hotel
loads,
industrial
cleaning,
desalinators.
Mr.
Magill
stated
that
a
typical
drill
ship
or
semi­
submersible
will
use
three
to
four
1,500
HP
engines
to
provide
operating
power
and
also
use
other
engines
for
auxiliary
back­
up
power
for
fire
fighting
and
emergency
situations.

Q:
Would
CWI
retrofits
cause
problems
with
hull
design,
load
paths,
and
fatigue?

Mr.
Magill
stated
that
a
re­
designed
sea­
chest
with
a
bell
intake
set
back
approximately
four
feet
or
a
bell
or
funnel
shaped
cone
on
the
end
of
a
jack­
up
CWI
pipe
would
not
cause
the
problems
identified
by
Noble
Drilling.
However,
Mr.
Magill
also
stated
that
using
the
same
pipe
diameter
(
e.
g.,
4
to
6
feet)
from
the
CWI
structure
to
the
top
of
the
jack­
up
rig
would
however
be
a
major
undertaking
and
may
cause
additional
concerns
similar
to
the
ones
identified
by
Noble
Drilling.
Page
4
of
4
Attachment
­
Review
of
Draft
Memorandum
From:
Magill,
James
<
Jmagill@
comdt.
uscg.
mil>
To:
Carey
Johnston/
DC/
USEPA/
US
Cc:
Prescott,
Mark
CDR
<
MPrescott@
comdt.
uscg.
mil>
Date:
05/
07/
01
07:
26
AM
Re:
draft
summary
meeting
notes
Carey,
Your
draft
notes
on
our
meeting
look
good.
I
have
only
one
small
change:­
On
page
3,
Q:
What
is
the
typical
depth
below
water
of
sea
chests?

When
semi­
submersibles
are
drilling
their
sea
chests
are
80
to
100
feet
below
the
water
surface
and
are
less
than
20
feet
below
water
when
the
pontoons
are
raised
for
transit
or
screen
cleaning
operations.
Drill
ships
have
their
sea
chests
on
the
bottom
of
their
hulls
and
are
typically
20
feet
or
more
below
the
water
at
all
times.

As
you
see
I
have
changed
the
last
sentence,
as
the
draft
of
drill
ships,
depending
on
their
size,
is
usually
from
20
to
40
feet.
If
I
can
be
of
any
further
assistance
please
do
not
hesitate
to
call
or
email

Jim
Magill
Offshore
Specialist,
G­
MSO­
2
Tel#
(
202)
267­
1082
Fax#
(
202)
2674570
E­
mail:
jmagill@
comdt.
uscg.
mil
­­­­­
Original
Message­­­­­
From:
Johnston.
Carey@
epamail.
epa.
gov
Sent:
Monday,
April
30,
2001
8:
35
AM
To:
Magill,
James
Subject:
RE:
draft
summary
meeting
notes
Dear
Jim:

Sorry
for
the
delay.
Here
is
the
file
in
*.
doc
format.
Please
let
me
know
if
you
have
any
more
problems
reading
the
file.
Thank
you
again
for
you
assistance.

Sincerely,
Carey
(
See
attached
file:
coastguard.
doc)
