Outer Continental Shelf Title V and PSD Permit Application

Emission Source Description 3

- 1 ENVIRON 

# 3 Emission Source Description

In this s ection of the permit application, we describe the emission s calculation basis for each

emission s unit proposed for the Developer and Discoverer Americas . As previously discussed

, Statoil is requesting flexibility to us e either the Developer or Discoverer Americas to perform exploration activities in its Desoto Canyon lease blocks

. T he Developer is presented as Operating Scenario 1

, and the Discoverer Americas is presented as Operating Scenario 2. Whether using the Developer or Discoverer Americas

, the potential annual emissions proposed with this permit application are based on approximately 180 days per calendar year of expl oration act ivit ies

. However, when Statoil begins the exploration activities proposed with this permit application , the actual daily average operating rates of the emissions unit s associated

with the specific drilling vessel may not be as high as the daily average operating rates corresponding to the 180 days per year potential emissions basis for the vessel . Therefore,
Statoil is requesting the establishment of annual operating rate and emission rate permit limits

, not a limit on the annual number of days of exploration activities

. For example , Statoil proposes the following annual fuel usage limits for the Developer engines and its associated OSV and crew boat engines rather than a 180 day per year limit

.

• Developer engines

– 2,652,180 gallons of diesel per year

• Developer OSV engines

– 796,086 gallons of diesel per year when within 25 miles of and servicing the Developer

• Developer crew boat engines

– 252,195 gallons of diesel per year when within 25 miles of and servicing the Developer

Alternatively , Sta toil proposes the following annual fuel usage limits for the Discoverer Americas engines and its associated OSV and crew boat engines rather than a 180 day per year limit.

• Discoverer Americas engines

– 2, 182

, 414 gallons of diesel per year

• Discoverer Ameri cas OSV engines

– 796,086 gallons of diesel per year when within 25 miles of and servicing the Developer

• Discoverer Americas crew boat engines

– 252,195 gallons of diesel per year when within 25 miles of and servicing the Developer

This section is organized as follows

. In Section 3.1 , we describe general emissions basis information that applies globally to the drilling and exploration activities proposed with this permit application. Section 3.2 presents the emission calculation basis for each of the

emission s units associated with the Developer , and Section 3.3 presents the same information

for the Discoverer Americas

. Lastly, Section 3. 4 describes emergency operations that could occur for the two drilling vessels and the emissions to the atmosph ere that would likely be related with these emergency operations

. Please see Appendix B of this permit application for

the d etailed potential emission s calculations d iscussed in this section.Outer Continental Shelf Title V and PSD Permit Application

Emission Source Description 3

- 2 ENVIRON 

### 3.1 General Emissions Basis Information

In t his section , we describe general emissions basis information that applies globally to the drilling and exploration activities proposed with this permit application.



### 3.1.1 Emission Factor Basis Development

The emissions calculations included in this permit application are base d on the most current EPA approved emissions estimating procedures, industry standard methods, best professional judgment, and the most accurate emissions estimating data believed to be available after reasonable inquiry. Below we describe the emission fa ctors used to estimate emissions from the diesel engines aboard the Developer and Discoverer Americas and associated support fleet

.

Emission factors serve as the basis of emissio n rate estimates for all diesel

- fired engines. Emission factors represent a quantity of emissions per unit of fuel consumed or unit of power produced. The emission factors that have been utilized to estimate emissions were derived from multiple sources as documented herein

.

Vendor Supplied Data

– The emission factor was supplied by the owner, operator, or
manufacturer of the emissions unit

. For engines, t he basis for vendor supplied data is typically engine test data, either in a test laboratory or during actual use.

Certification Level

– For an engine, t h is e mission factor would have been obtained from

documentation provided by t he engine manufacturer that certifies the engine emissions comply

with a r egulatory emissions limitation or standard

.

Mass Balance

– The e mission factor used to estimate sulfur dioxide ( SO 2 

### ) emissio ns from the

combustion of diesel in the engines located on the drilling vessels was calculated using a mass balance approach. The factor was based on the sulfur content (0.0 01 5 percent by weight ) of

the diesel fuel proposed to be combusted in the engines and an assumption that 100 percent of

the sulfur contained in the diesel will be oxidize d to SO 2



### . Th e noted sulfur content represents the specification required for ultra low sulfur diesel , which is the grade of diesel to be combusted in the engines

.

AP

- 42

– The e mission factor was obtained from EPA published AP

- 42 documents. Specifically,

f actors for large engines (>600 hp) were obtained from Section 3.4, Large Stationary Diesel and All Stationary Dual

- fuel Engines

, October 1996. Similarly, the emissio n f actors for small engines ( ≤ 600 hp) were obtained from Section 3.3, Gasoline and Diesel Industrial Engines

, October 1996. In some cases particulate matter (PM) size distribution information from AP

- 42 was applied to certification level PM data to calculate PM less than 10 microns ( PM 10 

### ) and PM less than 2.5 microns ( PM 2.5 

### ) emission factors. T hese cases are noted in this section with the following reference, “Certification & AP

- 42

. ”

EPA

– The e mission factor was obtained from an EPA published document other than AP

- 42

. Emission factors for carbon dioxide ( CO 2 

### ), methane ( CH 4 

### ), and nitrous oxide ( N 2 

### O ) resulting

from the combustion of diesel were obtained from Tables C

- 1 and C

- 2 of 40 CFR part 98

, s ubpart C

. These greenhouse gas ( GHG ) emissions were convert ed to carbon dioxideOuter Continental Shelf Title V and PSD Permit Application

Emission Source Description 3

- 3 ENVIRON 

### equivalent ( CO 2 

### e ) based on the respective g lobal w arming p otential identified for each of the pollutants i n Table A

- 1 of 40 CFR part 98, s ubpart A

. Additionally, the emission factor for lead resulting from the c ombustion of diesel was obtained from the following EPA document : Locating and Estimating Air Emissions from Sources of Lead and Lead Compounds ( 454

- R

- 98

- 006 ), May 1998. Finally, the following EPA document was used as a reference to consider

emissions of sulfuric acid mist and total reduced in association with the combustion of diesel: Draft Regulatory Impact Analysis: Control of Emissions from Nonroad Diesel Engines ( 420

- R

03

- 008 ), April 2003.



### 3.1.2 Sulfur Compound Emissions

As discussed above

, we have calculated SO 2 

### emissions from diesel

- fired engines on the basis

that 100 percent of the sulfur compounds in the diesel will be oxidized to SO 2



### . The sulfur compounds in diesel fuel do not include hydrogen sulfide (H 2 

### S). 1 

### Becaus e H 2 

### S is not a normal

constituent of diesel fuel and is not expected to be formed during combustion

, H 2 

### S emissions

from the combustion of diesel are considered negligible. 2



### In association with the determination of PSD applicability , we have calculated sulfuric acid mist ( H 2 

### SO 4 

### ) and total reduced sulfur (TRS) 3 

### emissions from diesel

- fired engines

. As previously

discussed

, when estimating potential SO 2 

### emissions from the diesel

- fired engines proposed in this permit application

, we have assumed that 100 pe rcent of the sulfur compounds in the diesel

are oxidized to SO 2



### . However, o ut of an abundance of caution, we have calculated potential

H 2 

### SO 4 

### and TRS emissions from diesel

- fired engines using information contained in the following draft EPA document : Draft Regulatory Impact Analysis: Control of Emissions from Nonroad Diesel Engines ( 420

- R

- 03

- 008 ), April 2003

.

Potential H 2 

### SO 4 

### emissions from diesel

- fired engines were estimated on the basis that 2.247 percent by weight of the sulfur in the diesel is converted to SO 4 

### , which is then converted to sulfuric acid. Similarly, potential TRS emissions were calculated on the basis that 1 percent by weight of the sulfur in the diesel is emitted as TRS rather than being oxidized to SO 2



### . Note that the 1 percent sulfur could be converted to TRS or reduced sulfur compounds (RSC)

. 4 

### With either designation, the potential emissions are considerably less than the relevant PSD significant level of 10 tpy. Please see Appendix B for the potential emission s calculations.



### 3.1.3 Fluor ide Emissions

Based on a literature review and internet search, no information was identified indicating there is the potential for fluoride emissions from the combustion of diesel fuel in internal combustion engines. Consistent with this concept , fluorin e

- containing compounds are not identified in the speciation profile of Distillate Fuel Oil No. 2 (diesel ) included in the EPA TANKS 4.09d p rogram

,

1 According to the speciation profile of Di stillate Fuel Oil No. 2 (diesel ) from the EPA TANKS 4.09d Program, hydrogen sulfi de is not a component of diesel

. 2 Based on AP

- 42

, Chapter 3.4, Large Stationary Diesel and All Stationary Dual

- fuel Engines

, (10/1996), hydrogen sulfide is not a speciated component of diesel combustion emissions. Furthermore, based on information p rovided in

this section of AP

- 42, all sulfur in the fuel is expected to be oxidized to SO 2

. 3 TRS compounds comprise hydrogen sulfide, methyl mercaptan, dimethyl sulfide, and dimethyl disulfide.

4 RSC compounds comprise hydrogen sulfide, carbonyl sulfide, and carbon disulfide.Outer Continental Shelf Title V and PSD Permit Application

Emission Source Description 3

- 4 ENVIRON 

### and no literature review or internet search indicated that fluorine

- containing compounds would be present in diesel fuel. As a result of these findings, fluoride emissions resulting from the combustion of diesel are considered negligible

. 5



### 3.1.4 Startup

, Shutdown , and Maintenance Emissions

Emissions associated with the start

- up and shutdown of the engines located on the Developer

and Discoverer Americas are accounted for in the potential emissions proposed for the engines

. Additionally, m aintenance will be performed on the diesel engines on a periodic basis in accordance with the procedures recommended by the particular engine manufacturer. However, emissions associated with such maintenance activities are accounted for in the potential emissions proposed for the engines. In summary, the proposed potential emissions for

the Developer and Di scoverer Americas emissions units are intended to cover start

- up, shutdown, and maintenance emissions

.



### 3.2 **Developer** Emis sion Calculation Basis

As previously discussed, t he use of the Developer is Operating Scenario 1. T he Developer will be supported by various support vessels operating within 25 miles its location

. The support

vessels will transport personnel and supplies to and from the drill ing vessel

. The D eveloper

do es not require towing or anchoring vessels because the vessel is self

- powered for transport

and d ynamically positioned when operating at the drilling location.

The following table summarizes the emissions units that are proposed for the Developer

.

Table 3. 2

- 1 **Developer** Emission s Units

Emissions Unit ID Source Description Quantity

GEN

- 1 thru GEN

- 8 Main Generator Engine s 8

E GEN Emergency Generator Engine 1

CMU

- 1 and CMU

- 2 Cement Unit Engines 2

LB Life b o at Engines 4

MOB Fast Rescue Boat Engine 1

FO ST Fuel Oil Storage Tanks 4

FO SER ST Fuel Oil Service Tanks 2

FO SET ST Fuel Oil Settling Tanks 2

FO E GEN ST Emergency Generator Fuel Oil Tank 1

FO CMV ST Cement Unit Fuel Oil Tank 1

FO LB ST Life b oat Fuel Tank s 1 per lifeboat

FO MOB ST Fast Rescue Boat Fuel Tank 1

AV ST Aviation Fuel Tanks 3

5 Based on AP

- 42

, Chapter 3.4, Large Stationary Diesel and All Stationary Dual

- fuel Engines

, (10/1996), fluoride is not a speciated component of diesel combustion emissions.Outer Continental Shelf Title V and PSD Permit Application

Emission Source Description 3

- 5 ENVIRON Emissions Unit ID Source Description Quantity

WO ST Waste Oil Tanks 2

FUG Fugitive Component Emissions

-
OSV Offshore Support Vessels Multiple

CREW Crew Boats Multiple



### Note that the wireline units (also referred to as “logging units”) located on the Developer will be electric powered. Therefore, the units will not be directly powered by an internal combustion engine.

In t he sections below, we discuss in detail the proposed potential emissions basis for each of

the e mission s units identified in the above table

.



### 3.2.1 Main Generator Engines

The main gener ator e ngines located on the Developer represent t he “main” electric power generating engines on the drilling vessel. T here are eight identical 6,6 51 hp (4,9 60 kW) main generator engines on the Developer , and th ese engines were manufactured by Wärtsilä Corporation . The following summarizes the proposed operating basis for the main generator

e ngines on the vessel

.

• “Normal Operations” Basis

– The “Normal Operations” basis consists of operating

three eng ines at 6 0% load while the remain in g five engines are on standby at 0%

load. Note that the proposed allowable annual emissions will apply to all of the engines as a group , which provides flexibility to operate any combination of the engines.

• Maximum Hourly Emissio ns Basis

– The maximum h ourly e mission s basis consist s of operating five engine s at 6 0% load while the three remaining engines are on standby at 0% load. This scenario accounts for the most engines running during any given hour of operation at their highest power rating. Note that the proposed allowable maximum hourly emission rate limits will apply to all of the engines as a
group

, which provides flexibility to operat e any combination of the engines

.

The table below summarizes key operating parameters that are the basis of the emission

calculations for the main g enerator e ngines

.

Table 3. 2 .1

- 1

Main Generator Engine Op erating Parameters

Emission s

Unit ID Maximum Power Rating (kW) Normal Operation Power Rating (kW) Normal Operation
Annual Hours (hr/yr) Maximum Hourly Power Rating (kW)

GEN

- 1 4,960 2,976 4,320 2,976

GEN

- 2 4,960 2,976 4,320 2,976Outer Continental Shelf Title V and PSD Permit Application

Emission Source Description 3

- 6 ENVIRON Emissions

Unit ID Maximum Power Rating (kW) Normal Operation Power Rating (kW) Normal Operation
Annual Hours (hr/yr) Maximum Hourly Power Rating (kW)

GEN

- 3 4,960 2,976 4,320 2,976

GEN

- 4 4,960 0 4,320 2,976

GEN

- 5 4,960 0 4,320 2,976

GEN

- 6 4,960 0 4,320 0

GEN

- 7 4,960 0 4,320 0

GEN

- 8 4,960 0 4,320 0



### Below is a summary of the emission factors used to calculate annual and maximum hourly emissions for the main generator engines installed on the Developer

.

Table 3. 2 .1

- 2 Main Generator Engine Emission Factors

Pollutant Emission Factor (g/kW

- hr) Emission Factor Basis

Total VOC 0.43 AP

- 42

NO
x 8.16 Vendor Supplied Data

SO 2 0.007 Mass Balance

CO 0.39 Vendor Supplied Data

PM 0.15 Vendor Supplied Data

PM 10 0.15 Vendor Supplied Data

PM 2.5 0.15 Vendor Supplied Data

CO 2 e 696.6 EPA

Lead 1.23E

- 04 EPA

Benzene 3.30E

- 03 AP

- 42

Toluene 1.20E

- 03 AP

- 42

Xylenes 8.22E

- 04 AP

- 42

Formaldehyde 3.36E

- 04 AP

- 42

Acetaldehyde 1.07E

- 04 AP

- 42

Acrolein 3.36E

- 05 AP

- 42

Naphthalene 5.54E

- 04 AP

- 42



### 3.2.2 Cement Unit Engines

The Developer is equipped with two cementing units that produce cement that is pumped around the outside of the casing during the drilling process to stabilize the casing. Each

cement ing unit is equipped with a 500 hp ( 373 kW) diesel

- fired engine . The table below

summarizes the key operating parameters t hat are the basis of the potential emission

calculations for the cement unit engines

. The maximum hourly emissions for each engine are based on running the engine at 100% capacity for an entire hour

.Outer Continental Shelf Title V and PSD Permit Application

Emission Source Description 3

- 7 ENVIRON 

### Table 3. 2 .2

- 1
Cement Unit Engine Operating Summary

Emissions Unit
ID Source Description Maximum Power Rating (kW) Run Time (hr/yr)

CMU

- 1 Cement Unit Engine #1 373 60

C MU

- 2 Cement Unit Engine #2 373 60



### Below is a summary of the emission factors used to calculate annual and maximum hourly emissions for the cement unit engines installed on the Developer

.

Table 3. 2

. 2

- 2
Cement Unit Engine Emission Factors

Pollutant Emission Factor (g/kW

- hr) Emission Factor Basis

Total VOC 1.53 AP

- 42

NO
x 7.2 Certification

SO 2 0.007 Mass Balance

CO 5.00 Certification

PM 0.20 Certification

PM 10 0.16 Certification & AP

- 42

PM 2.5 0.16 Certification & AP

- 42

CO 2 e 696.60 EPA

Lead 1.23E

- 04 EPA

Benzene 3.97E

- 03 AP

- 42

Toluene 1.74E

- 03 AP

- 42

Xylenes 1.21E

- 03 AP

- 42

Formaldehyde 5.02E

- 03 AP

- 42

Acetaldehyde 3.27E

- 03 AP

- 42

Acrolein 3.94E

- 04 AP

- 42

Naphthalene 3.61E

- 04 AP

- 42

1,3

- Butadiene 1.66E

- 04 AP

- 42



### 3.2.3 Emergency Generator Engine s

The Developer is equipped with an emergency generator driven by a 2,551 hp (1,902 kW) diesel engine . T he emergency generator engine is operated during maintenance checks or in the event of an emergency. The engine is planned to be operat ed for 6.7 hours per month, wi th

one

- half of this time for normal engine testing and maintenance hours and the other half for expected emergency use of the engine based on past operations

. The table below summarizes the key operating parameters that are the basis of the potential emission s calculations for the emergency generator engine. The maximum hourly emissions for the engine are based on running the engine at 100% capacity for an entire hour.Outer Continental Shelf Title V and PSD Permit Application

Emission Source Description 3

- 8 ENVIRON 

### Table 3. 2

. 3

- 1 Emergency Generator Engine Operating Summary

Emissions

Unit ID Source Description Maximum Power Rating (kW) Run Time

hr/month hr/yr

EGEN Emergency Generator Engine 1,902 6.7 39



### Below is a summary of the emission factors used to calculate annual and maximum hourly emissions for the emergency generator engine installed on the Developer

.

Table 3. 2

. 3

- 2 Emergency Generator Emission F actors

Pollutant Emission Factor (g/kW

- hr) Emission Factor Basis

Total VOC 0.43 AP

- 42

NO
x 9.2 Certification

SO 2 0.007 Mass Balance

CO 3.35 AP

- 42

PM 0.30 AP

- 42

PM 10 0.244 AP

- 42

PM 2.5 0.237 AP

- 42

CO 2 e 696.60 EPA

Lead 1.23E

- 04 EPA

Benzene 3.30E

- 03 AP

- 42

Toluene 1.20E

- 03 AP

- 42

Xylenes 8.22E

- 04 AP

- 42

Formaldehyde 3.36E

- 04 AP

- 42

Acetaldehyde 1.07E

- 04 AP

- 42

Acrolein 3.36E

- 05 AP

- 42

Naphthalene 5.54E

- 04 AP

- 42



### 3.2.4 Life b oat Engines

The Developer is equipped with four lifebo ats. Each lifeboat is equipped with a 29 hp (22 kW) engine that is operated during maintenance checks, safety exercises, or in the event of an emergency. The planned operating time for maintenance of the engines is one hour per month,

which we have doubled to account for safety exercises. Since the potential emissions of regulat ed air pollutants are less than 2 tpy, and HAP emissions are less than 1,000 lb/yr, the

emission levels from the lifeboat engine s are considered insignificant per 40 CFR 71.5(c)(11)(ii)

and will be included as such in the permit application forms. The tab le below summarizes the key operating parameters that are the basis of the potential emissions calculations for the lifeboat engines.Outer Continental Shelf Title V and PSD Permit Application

Emission Source Description 3

- 9 ENVIRON 

### Table 3. 2

. 4

- 1

Life b oat Engine Operating Summary

Emissions Unit
ID Source Description Maximum Power Rating (kW) Run Time

hr/month hr/yr

LB

- 1 Lifeboat No. 1 Engine 22 2 12

LB

- 2 Lifeboat No. 2 Engine 22 2 12

LB

- 3 Lifeboat No. 3 Engine 22 2 12

LB

- 4 Lifeboat No. 4 Engine 22 2 12



### Furthermore, b elow is a summary of the emission factors used to calculate annual and maximum hourly emissions for the Developer life boat engines

.

Table 3. 2

. 4

- 2
Lifeb oat Engine Emission Factors

Pollutant Emission Factor (g/kW

- hr) Emission Factor Basis

Total VOC 1.53 AP

- 42

NO
x 7.5 Certification

SO 2 0.007 Mass Balance

CO 5.5 Certification

PM 0.60 Certification

PM 10 0.49 Certification & AP

- 42

PM 2.5 0.48 Certification & AP

- 42

CO 2 e 696.6 EPA

Lead 1.23E

- 04 EPA

Benzene 3.97E

- 03 AP

- 42

Toluene 1.74E

- 03 AP

- 42

Xylenes 1.21E

- 03 AP

- 42

Formaldehyde 5.02E

- 03 AP

- 42

Acetaldehyde 3.27E

- 03 AP

- 42

Acrolein 3.94E

- 04 AP

- 42

Naphthalene 3.61E

- 04 AP

- 42

1,3

- Butadiene 1.66E

- 04 AP

- 42



### 3.2.5 Fast Rescue Boat Engines

The Developer is equipped with one fast rescue boat. The fast rescue boat is commonly

referred to as a “man overboard boat ” or “MOB.” The fast rescue boat is equipped with a 163 hp ( 122 kW) engine that is operated during maintenance checks, safety exercises, or in the event of an emergency. The planned ope rating time for maintenance of the engine is one hour per month, which we have doubled to account for safety exercises. Since the potential emissions of regulated air pollutants are less than 2 tpy, and HAP emissions are less than 1,000 lb/yr, the emissio n levels from the fast rescue boat engines are considered insignificant per 40Outer Continental Shelf Title V and PSD Permit Application

Emission Source Description 3

- 10 ENVIRON 

### CFR 71.5(c)(11)(ii) and will be included as such in the permit application forms. The table below summarizes the key operating parameters that are the basis of the potential em issions
calculations for the fast rescue boat engine

.

Table 3. 2

. 5

- 1

F ast Rescue Boat Engine Operating Summary

Emissions Unit
ID Source Description Maximum Power Rating (kW) Run Time

hr/month hr/yr

MOB Fast Rescue Boat Engine 1 22 2 12



### Below is a summary of the emission factors used to calculate annual and maximum hourly emissions for the fast rescue boat engine on the Developer

.

Table 3. 2

. 5

- 2

Fast Rescue Boat Engine Emission Factors

Pollutant Emission Factor (g/kW

- hr) Emission Factor Basis

Total VOC 1.53 AP

- 42

NO
x 7.50 Certification

SO 2 0.007 Mass Balance

CO 5.00 Certification

PM 0.40 Certification

PM 10 0.33 Certification & AP

- 42

PM 2.5 0.32 Certification & AP

- 42

CO 2 e 696.6 EPA

Lead 1.23E

- 04 EPA

Benzene 3.97E

- 03 AP

- 42

Toluene 1.74E

- 03 AP

- 42

Xylenes 1.21E

- 03 AP

- 42

Formaldehyde 5.02E

- 03 AP

- 42

Acetaldehyde 3.27E

- 03 AP

- 42

Acrolein 3.94E

- 04 AP

- 42

Naphthalene 3.61E

- 04 AP

- 42

1,3

- Butadiene 1.66E

- 04 AP

- 42



### 3.2.6 Storage Vessels

Emissions are gener ated from the storage of fuel and waste oil in tanks ab oard the Developer

. D iesel 6 

### is used in the engines installed on the drilling vessel as well as the vessel’s lifeboat and

fast rescue boat engines

. Additionally , there are three storage tanks for a viation f uel , which is

6 Marine gas oil, diesel fuel, and distillate fuel oil No. 2 all have very similar properties and are collectively referred to

as “diesel” in this permit application.Outer Continental Shelf Title V and PSD Permit Application

Emission Source Description 3

- 11 ENVIRON 

### used to refuel helicopters. Finally, there are two storage tanks on the drilling vessel that are

used to store waste oil that is collected from fuel system strai ners, filters, and separators.

The EPA TANKS 4.09d computer software program was used to calc ulate the potential working and breathing emissions from the storage vessels located on the Developer

. The default EPA
TANKS 4.09d properties for Distillate Fuel Oil No. 2 were used to calculate emissions for the

d iesel and waste oil storage tanks

. Addit ionally, the default EPA TANKS 4.09d properties for Jet Naphtha were used to calculate emissions for the a viation f uel storage tanks

. For a particular storage tank, t he maximum hourly emissions were estimated by dividing the annual

emissions calculated for the tank using EPA TANKS 4.09d by the tank’s annual hours of operation

.

Since the potential emissions of regulated air pollutants are less than 2 tpy, and HAP emissions are less than 1,000 lb/yr, the emission levels from the storage tanks a re considered insignificant per 40 CFR 71.5(c)(11)(ii) and will be included as such in the permit application forms. The table below summarizes key design and operating parameters that are the basis of the potential emissions calculations for the storage vessels

.

Table 3. 2

. 6

- 1 Storage Vessel Inventory and Operating Summary

Emissions

Unit ID Source Description Capacity Working Capacity

(gal) Throughput (gal/yr) m 3 gal

FO ST Pontoon Fuel Oil Tank No. 1 ( P ) 1,305 344,715 310,244 700,000

Pontoon Fuel Oil Tank No. 2 (S) 1,305 344,715 310,244 700,000

Pontoon Fuel Oil Tank No. 3 (P ) 875 231,087 207,978 700,000

Pontoon Fuel Oil Tank No. 4 (S) 875 231,087 207,978 700,000

FO SER ST Upper Hull Fuel Oil Tank No. 1 (P) 49 12,815 11,533 1,400,000

Upper Hull Fuel Oil Tank No. 2 (S) 57 14,952 13,457 1,400,000

FO SET ST Upper Hull Fuel Oil Tank No. 3 (P) 34 8,948 8,053 1,400,000

Upper Hull Fuel Oil Tank No. 4 (S) 35 9,230 8,307 1,400,000

FO E GEN ST Emergency Generator Fuel Oil
Tank 8 2,113 1,902 5,000

FO CMV ST Cement Unit Fuel Oil Tank 2 549 495 4,000

FO LB ST Life b oat No. 1 Fuel Tank 0.2 45 40 20

Life b oat No. 2 Fuel Tank 0.2 45 40 20

Life b oat No. 3 Fuel Tank 0.2 45 40 20

Life b oat No. 4 Fuel Tank 0.2 45 40 20

FO MOB ST Fast Rescue Boat Fuel Tank 0.2 45 40 100

AV ST Aviation Fuel Tank No. 1 3 748 673 121,112

Aviation Fuel Tank No. 2 3 748 673 121,112

Aviation Fuel Tank No. 3 3 748 673 121,112

WO ST Waste Oil Tank No. 1 (P) 35 9,125 8,212 8,212

Waste Oil Tank No. 2 (S) 35 9,125 8,212 8,212Outer Continental Shelf Title V and PSD Permit Application

Emission Source Description 3

- 12 ENVIRON 

### 3.2.7 Fugitive Component s

The Developer is equipped with piping and associated piping fugitive components that are used to convey fuel and waste oil on the vessel

. Fugitive component counts were estimated based

on a review of the Developer f uel s ystem piping and instrumentation diagrams ( P&IDs )

. Fugitive emissions have been calculated based on the number of component s and the material contained or contacted by the component s . The table below summarizes the component counts by service on the Deve loper

.

Table 3. 2

. 7

- 1 Fugitive Component Emissions

Component Type Number of Fuel Service Components Number of Waste Oil
Service Components

Valve 263 4

Flange 525 8
Pump Seal 6 0

Other 36 0



### T he potential emissions for the fugitive components have been calculated using the oil and gas production operations average emission factors included in Table 2

- 4 of the Protocol for Equipment Leak Emission Estimates ( EPA

- 453/R

- 95

- 017 ), November 1995 and the composition of the material to be contained or contacted by the components. Because a “heavy oil” pump emission factor was not identified, w e used t he “ l ight o il ” pump emission factor for all of the

pumps on the drilling vessel

. For “ o ther ” component types, we used the “heavy oil” emission

factor because the large majority of c omponents on the vessel are in diesel service. Finally,

Table 2

- 4 identifies separate emission factors for flanges and connectors. We conservatively used the higher of the fla nge and connector emission factors identified in the table to estimate emissions from the flanges/connectors located on the vessel. The emission factors used in the potential emissions calculations for fugitive emissions are summarized in the table below.

Table 3. 2

. 7

- 2 Fugitive Component Emission Factors

Service Valves (kg/hr/source) Connectors (kg/hr/source) Pumps (kg/hr/source) Other (kg/hr/source)

Diesel 8.4 E

- 06 7.5 E

- 06 1.3 E

- 02 3.2 E

- 05

Waste Oil 9.8 E

- 05 1.1 E

- 04 2.4 E

- 05 3.2 E

- 05



### 3.2.8 Support Vessels

S pecific support vessels are not solely dedicated to a particular drilling campaign. Instead

, Statoil relies on a support vessel fleet made up of many different vessels that fall into one of two support vessel categories. Note that the proposed potential emissions included in this application for the Developer support vessels will apply to any support vessel that Statoil may

use with the drilling vessel , which is expecte d to provide S tatoil with the flexibility to utilize any

vessel fr om the support vessel fleet to meet project needs. Additionally, a direct physical

connection between the drilling vessel and a support vessel is an unusual event. Normally

, theOuter Continental Shelf Title V and PSD Permit Application

Emission Source Description 3

- 13 ENVIRON 

### support vessels will be under their ow n power when adjacent to the drilling vessel for loading or unloading purposes. The only expected physical connection between the drilling vessel and a support vessel would be product transfer hoses such as those necessary for the transfer of f uel

or dril ling mud between the vessels

.

To estimate annual emissions from the engines of each type of support vessel, Statoil estimated the total hours of operation of the particular vessel

- type during the proposed drilling campaign (180 days) based on actual hours of operation for similar vessels during historical drilling campaigns. Statoil used the actual hours of operation (with a safety buffer) in conjunction with emission factors (certification, AP

- 42, etc.) to estimate annual emissions associated with the

su pport vessel operations. To estimate maximum hourly emissions for each support vessel type, Statoil gathered specific engine data and emissions information for several vessels in each category. From that information, Statoil derived the emissions that co uld reasonably be expected from each type of support vessel during the drilling campaign. While actual emissions will vary between different vessels, the potential support vessel emissions proposed in this application are a reasonable estimate of the emis sions expected from a typical support vessel in each category.



### 3.2.8.1 Offshore Support Vessel Engines
OSVs transport personnel and supplies to and from the drilling vessel

. OSVs are equipped with large engines that power generators, thrusters, and main propulsion devices . Additionally, the OSVs are equipped with small engines that are used to power emergency generators. Statoil used the engine inventory on the OSV Peyton Candies to represent typical engine emissions
from an OSV

.

The potential a nnual e ngine emissions from an OSV have been calculated based on the

estimated annual hours of operation of each engine on the vessel

. Maximum hourly engine

emissions from an OSV have been estimated by assuming each en gine on the vessel operates

at its highest l oad capacity for the hour

. As previously noted, actual engine emissions may vary
with different OSVs , but the potential OSV engine emissions proposed with this application are representative of a typical OSV

. The table below summarizes the key operating parameters that are the basis of the potential emissions calculations for the OSV engines.

Table 3. 2

. 8.1

- 1 Offshore Support Vessel Engine Operating Summary

Emissions

Unit ID Source Description Maximum Power Rating (kW) Normal Operation Power Rating (kW) N ormal Operation
Annual Hours (hr/yr) Maximum Hourly Power Rating (kW)

OSV OSV Main Engine No. 1 1,765 1,765 3,059 1,765

OSV Main Engine No. 2 1,765 1,765 3,059 1,765

OSV Main Engine No. 3 1,765 0 3,059 1,765

OSV Main Engine No. 4 1,765 0 3,059 1,765

OSV Emergency
Generator Engine 269 269 3,059 269Outer Continental Shelf Title V and PSD Permit Application

Emission Source Description 3

- 14 ENVIRON 

### Below is a summary of the emission factors used to calculate annual and maximum hourly emissions for the engines on the OSVs that will be associated with the Developer

.

Table 3. 2

. 8.1

- 2 Offshore Support Vessel Engine Emission Factors

Pollutant Main Engine
Emission Factor (g/kW

- hr) Emergency
Generator
Emission Factor (g/kW

- hr) Emission Factor Basis

Total VOC 0.43 1.53 AP

- 42

NO x 7.20 7.20 Certification

SO 2 0.007 0.007 Mass Balance

CO 3.35 4.06 AP

- 42

PM 0.20 0.20 Certification

PM 10 0.16 0.16 Certification

PM 2.5 0.16 0.16 Certification

CO 2 e 696.60 696.60 EPA

Lead 1.23E

- 04 1.23E

- 04 EPA

Benzene 3.30E

- 03 3.97E

- 03 AP

- 42

Toluene 1.20E

- 03 1.74E

- 03 AP

- 42

Xylenes 8.22E

- 04 1.21E

- 03 AP

- 42

Formaldehyde 3.36E

- 04 5.02E

- 03 AP

- 42

Acetaldehyde 1.07E

- 04 3.27E

- 03 AP

- 42

Acrolein 3.36E

- 05 3.94E

- 04 AP

- 42

Naphthalene 5.54E

- 04 3.61E

- 04 AP

- 42

1,3

- Butadiene

-- 1.66E

- 04 AP

- 42



### 3.2.8.2 Crew B oat Engine s

The crew boats transport pe rsonnel and supplies to and from the drilling vessel. Statoil does not currently know which specific vessel or vessels will serve as a crew boat during the proposed drilling campaign. Therefore

, potential crew boat engine emissions have been

estimated us ing an example of the type and size of crew boat that will be used by Statoil

.

Statoil used the engine inventory on the crew boat Sybil Graham to represent typical engine

emissions from a crew boat . While actual crew boat engine emissions may vary with d ifferent

crew boats, the potential crew boat engine emissions proposed with this application are representative of a typical crew boat

. The table below summarizes the key operating parameters that are the basis of the potential emissions calculations for the crew boat engines.Outer Continental Shelf Title V and PSD Permit Application

Emission Source Description 3

- 15 ENVIRON 

### Table 3. 2

. 8.2

- 1
Crew B oat Engine Operating Summary

Emissions

Unit ID Source Description Maximum Power Rating (kW) Normal Operation Power Rating (kW) Normal Operation
Annual Hours (hr/yr) Maximum Hourly Power Rating (kW)

CREW Main Engine No. 1 1,342 1,342 618 1,342

Main Engine No. 2 1,342 1,342 618 1,342

Main Engine No. 3 1,342 1,342 618 1,342

Main Engine No. 4 1,342 1,342 618 1,342

Emergency Generator Engine No. 1 93 93 618 93

Emergency Generator Engine No. 2 93 93 618 93

Thruster #1 Engine 201 201 618 201

Thruster #2 Engine 201 201 618 201



### Below is a summary of the emission factors used to calculate annual and maximum hourly emissions for the engines on the crew boats that will be associated with the Developer

.

Table 3. 2

. 8.2

- 2
Crew B oat Engine Emission Factors

Pollutant Large Engine
Emission Factor (g/kW

- hr) Small Engine
Emission Factor (g/kW

- hr) Emission Factor Basis

Total VOC 0.43 1.53 AP

- 42

NO x 7.20 7.20 Certification

SO 2 0.007 0.007 Mass Balance

CO 3.35 4.06 AP

- 42

PM 0.20 0.30/0.20 Certification

PM 10 0.16 0.25/0.16 Certification

PM 2.5 0.16 0.24/0.16 Certification

CO 2 e 696.60 696.60 EPA

Lead 1.23E

- 04 1.23E

- 04 EPA

Benzene 3.30E

- 03 3.97E

- 03 AP

- 42

Toluene 1.20E

- 03 1.74E

- 03 AP

- 42

Xylenes 8.22E

- 04 1.21E

- 03 AP

- 42

Formaldehyde 3.36E

- 04 5.02E

- 03 AP

- 42

Acetaldehyde 1.07E

- 04 3.27E

- 03 AP

- 42

Acrolein 3.36E

- 05 3.94E

- 04 AP

- 42

Naphthalene 5.54E

- 04 3.61E

- 04 AP

- 42

1,3

- Butadiene

-- 1.66E

- 04 AP

- 42Outer Continental Shelf Title V and PSD Permit Application

Emission Source Description 3

- 16 ENVIRON 

### 3.2.8.3 Drilling Mud
Drilling fluid (mud) is circulated between the drilling vessel and well during the drilling process to lubricate and cool the drill bit and transport drill cuttings. Additionally, the mud is needed to exert hydrostatic pressure in the well to prevent an influx of the formation’s fluids into the well

bore. When the mud is circulated from the well to the drilling vessel, it is exposed to the atmosphere and the gas entrained in the mud , which can include hydrocarbons, flashes out of the mud to the atmosphere. Emissions may come fr om any of the drilling mud equipment

, including the shaker room and mud pit/tanks. T he only appreciable hydrocarbon gases entrained in the mud are from rock cuttings generated when the drill bit pass es through rock that is within a hydrocarbon zone. Stat oil estimates that it will only encounter one day of appreciable hydrocarbon

- containing rock per well drilled, and it is anticipated that Statoil will drill four wells during the drilling campaign. The following EPA document serves as the basis fo r the dr illing mud operations potential emissions calculations: Atmospheric Emissions from Offshore Oil and Gas Development and Production ( 450/3

- 77/026 ) , June 1977

.

Below is a summary of the operating and emission factors used to calculate annual and maximum hourly emissions for the drilling mud operations on the Developer

. Since potential emissions of regulated air pollutants are less than 2 tpy, and HAP emissions a re less than 1,000 lb/yr, the emission levels from drilling mud are considered insignificant per 40 CFR 71.5(c)(11)(ii) and will be included as such in the application forms.

Table 3. 2

. 8.3

- 1 Drilling Mud Operating Summary and Emission Factors

Pollutant An nual N umber of
Wells Drilled

(wells/yr) Emission Factor (lb/well) Emission Factor
Basis

Total VOC 4 238.18 EPA

CO 2 e 12,057.49 EPA



### 3.3 **Discoverer Americas** Emis sion Calculation Basis

As previously discussed

, the use of the Discoverer Americas is Operating Scenario 2

. Similar to

the Developer, the Discoverer Americas will be supported by various support vessels operating
within 25 miles of its location

. The support vessels will transport personnel and supplies to and

from the drill ing vessel

. The Discoverer Americas drilling vessel do es not require towing or anchoring vessels because the vessel is self

- powered for transport and d ynamically positioned when operating at the drilling location.

The following table summarizes the emissions units that a re proposed for the Discoverer

Americas

.

Table 3. 3

- 1

**Discoverer Americas** Emission s Units

Emissions Unit ID Source Description Quantity

GEN

- 1 thru GEN

- 6 Main Generator Engine s 6Outer Continental Shelf Title V and PSD Permit Application

Emission Source Description 3

- 17 ENVIRON Emissions Unit ID Source Description Quantity

E GEN Emergency Generator Engine 1

ACOMP

- 1 and ACOMP

- 2 Emergency Air Compressor Engines 2

LB Life b oat Engines 6

MOB Fast Rescue Boat Engine 1

FO ST Fuel Oil Storage Tank s 3

FO SER ST Fuel Oil Service Tank s 2

FO SET ST Fuel Oil Settling Tank s 2

FO E GEN ST Emergency Generator Fuel Oil Tank 1

FO LB ST Life b oat Fuel Tank s 1 per lifeboat

FO MOB ST Fast Rescue Boat Fuel Tank 1

AV ST Aviation Fuel Tank 1

WS ST Waste Oil Tanks 2

FUG Fugitive Component Emissions

-
HTR Hot Oil Heater 1

OSV Offshore Support Vessels Multiple

CREW Crew Boats Multiple



### Note that the wireline units located on the Discoverer Americas will be electric powered. Therefore, the units will not be directly powered by an internal combustion engine.

In t he sections below, we discuss in detail the proposed potential emissions basis for each of

the emission s units identified in the above table

.



### 3.3.1 Main Generator Engines

The main generator engines located on the Discoverer Americas represent the “main” electric

power gene rating engines on the drilling vessel. There are six identical 9,387 hp (7,000 kW) main generator engines on the Discoverer Americas , and these engines were manufactured by
STX Engine Company . The following summarizes the proposed operating basis for the main generator engines on the vessel.

• “Normal Operations” Basis

– The “Normal Operations” basis consists of operating three engines at 35 % load while the remaining three engines are on standby at 0% load. Note that the proposed allowable annual emissions will apply to all of the engines as a group, which provides flexibility to operate any combination of the engines.

• Maximum Hourly Emissions Basis

– The maximum hourly em issions basis consists of operating four engines at 8 0% load while the two remaining engines are on standby at 0% load. This scenario accounts for the most engines running during any given hour of operation at their highest power rating. Note that the pr oposedOuter Continental Shelf Title V and PSD Permit Application

Emission Source Description 3

- 18 ENVIRON 

### allowable maximum hourly emission rate limits will apply to all of the engines as a group, which provides flexibility to operate any combination of the engines.

The table below summarizes key operating parameters that are the basis of the emission calculations for the main g enerator e ngines

.

Table 3 .3 .1

- 1

Main Generator Engine Operating Parameters

Emissions

Unit ID Maximum Power Rating (kW) Normal Operation Power Rating (kW) Normal Operation
Annual Hours (hr/yr) Maximum Hourly Power Rating (kW)

GEN

- 1 7,000 2,450 4,320 5,600

GEN

- 2 7,000 2,450 4,320 5,600

GEN

- 3 7,000 2,450 4,320 5,600

GEN

- 4 7,000 0 4,320 5,600

GEN

- 5 7,000 0 4,320 0

GEN

- 6 7,000 0 4,320 0



### Below is a summary of the emission factors used to calculate annual and maximum hourly emissions for the main generator engines installed on the D iscoverer Americas

.

Table 3

. 3 .1

- 2

Main Generator Engine Emission Factors

Pollutant Emission Factor (g/kW

- hr) Emission Factor Basis

Total VOC 0.43 AP

- 42

NO
x 12.1 (Avg.)/10.29 (Max.) Certification/Vendor Supplied

SO 2 0.007 Mass Balance

CO 0.37 (Avg.) / 0.18 (Max.) Vendor Supplied/Vendor Supplied

PM 0.15 Certification

PM 10 0.15 Certification

PM 2.5 0.15 Certification

CO 2 e 696.60 EPA

Lead 1.23E

- 04 EPA

Benzene 3.30E

- 03 AP

- 42

Toluene 1.20E

- 03 AP

- 42

Xylenes 8.22E

- 04 AP

- 42

Formaldehyde 3.36E

- 04 AP

- 42

Acetaldehyde 1.07E

- 04 AP

- 42

Acrolein 3.36E

- 05 AP

- 42

Naphthalene 5.54E

- 04 AP

- 42Outer Continental Shelf Title V and PSD Permit Application

Emission Source Description 3

- 19 ENVIRON 

### 3.3.2 Emergency Generator Engine s

The Discoverer Americas is equipped with an emergency generator driven by a 3,097 hp (2,309 kW) diesel engine. The emergency generator engine is operated during maintenance checks or in the event of an emergency. The engine is planned to be operated for 7.0 hours per month,

wi th one

- half of this time for normal engine testing and maintenance hours and the other half for expected emergency use of the engine based on past operations. The table below summarizes the key operating parameters that are the basis of the potential emis sions calculations for the emergency generator engine. The maximum hourly emissions for the engine are based on running the engine at 100% capacity for an entire hour.

Table 3

. 3

. 2

- 1 Emergency Generator Engine Operating Summary

Emissions

Unit ID Source De scription Maximum Power Rating (kW) Run Time

hr/month hr/yr

EGEN Emergency Generator Engine 2

, 309 7.0 41



### Below is a summary of the emission factors used to calculate annual and maximum hourly emissions for the emergency generator engine installed on the Discoverer Americas

.

Table 3 .3

. 2

- 2 Emerg ency Generator Engine Emission Factors

Pollutant Emission Factor (g/kW

- hr) Emission Factor Basis

Total VOC 0.43 AP

- 42

NO
x 9.80 Certification

SO 2 0.007 Mass Balance

CO 0.26 Vendor Supplied

PM 0.30 AP

- 42

PM 10 0.244 AP

- 42

PM 2.5 0.237 AP

- 42

CO 2 e 696.60 EPA

Lead 1.23E

- 04 EPA

Benzene 3.30E

- 03 AP

- 42

Toluene 1.20E

- 03 AP

- 42

Xylenes 8.22E

- 04 AP

- 42

Formaldehyde 3.36E

- 04 AP

- 42

Acetaldehyde 1.07E

- 04 AP

- 42

Acrolein 3.36E

- 05 AP

- 42

Naphthalene 5.54E

- 04 AP

- 42Outer Continental Shelf Title V and PSD Permit Application

Emission Source Description 3

- 20 ENVIRON 

### 3.3.3 E mergency Air Compressor Engines

The Discoverer Americas is equipped with two backup air compressors, each driven by a diesel engine. The backup air compressors are used when the primary air compressors are not operational. The emergency air compressor engines are operated during maintenance checks, safety ex ercises, or in the event of an emergency. Each engine is planned to be operated for 1.0 hour per month for normal engine maintenance, testing, and expected emergency use. Since the potential emissions of regulated air pollutants are less than 2 tpy, and HAP emissions are less than 1,000 lb/yr, the emission levels from the storage tanks are considered insignificant per 40 CFR 71.5(c)(11)(ii) and will be included as such in the permit application forms. The table below summarizes the key operating paramete rs that are the basis of the potential emission calculations for the emergency air compressor engines. The maximum hourly emissions for each engine are based on running the engine at 100% capacity for an entire hour.

Table 3.3. 3

- 1 Emergency Air Compresso r Engine Operati ng Summary

Emissions

Unit ID Source Description Maximum Power Rating (kW) Run Time

hr/month hr/yr

ACOMP

- 1 Emergency Air Compressor Engine No. 1 37 1 6

ACOMP

- 2 Emergency Air Compressor Engine No. 2 51 1 6



### Below is a summary of the emission factors used to calculate annual and maximum hourly emissions for the emergency air compressor engines installed on the Discoverer Americas

.

Table 3.3. 3

- 2 Emergency Air Compressor Engine Emission Factors

Pollutant Emission Factor (g/kW

- hr) Emission Factor Basis

Total VOC 1.53 AP

- 42

NO
x 7.50 Certification

SO 2 0.007 Mass Balance

CO 5.00 Certification

PM 0.40 Certification

PM 10 0.33 Certification & AP

- 42

PM 2.5 0.32 Certification & AP

- 42

CO 2 e 696.60 EPA

Lead 1.23E

- 04 EPA

Benzene 3.97E

- 03 AP

- 42

Toluene 1.74E

- 03 AP

- 42

Xylenes 1.21E

- 03 AP

- 42Outer Continental Shelf Title V and PSD Permit Application

Emission Source Description 3

- 21 ENVIRON Pollutant Emission Factor (g/kW

- hr) Emission Factor Basis

Formaldehyde 5.02E

- 03 AP

- 42

Acetaldehyde 3.27E

- 03 AP

- 42

Acrolein 3.94E

- 04 AP

- 42

Naphthalene 3.61E

- 04 AP

- 42

1,3

- Butadiene 1.66E

- 04 AP

- 42



### 3.3.4 Life b oat Engines

The Discoverer Americas is equipped with six lifeboats. Each lifeboat is equipped with a 36 hp (27 kW) engine that is operated during maintenance checks, safety exercises, or in the event of an emergency. The planned operating time for maintenance of the eng ines is one hour per month, which we have doubled to account for safety exercises. Since the potential emissions of regulated air pollutants are less than 2 tpy, and HAP emissions are less than 1,000 lb/yr, the emission levels from the lifeboat engines ar e considered insignificant per 40 CFR 71.5(c)(11)(ii) and will be included as such in the permit application forms. The table below summarizes the key operating parameters that are the basis of the potential emissions calculations for the lifeboat engines

.

Table 3 .3

. 4

- 1

Life b oat Engine Operati ng Summary

Emissions Unit
ID Source Description Maximum Power Rating (kW) Run Time

hr/month hr/yr

LB

- 1 Lifeboat No. 1 Engine 2 7 2 12

LB

- 2 Lifeboat No. 2 Engine 27 2 12

LB

- 3 Lifeboat No. 3 Engine 27 2 12

LB

- 4 Lifeboat No. 4 Engine 27 2 12

LB

- 5 Lifeboat No. 5 Engine 27 2 12

LB

- 6 Lifeboat No. 6 Engine 27 2 12



### Furthermore, below is a summary of the emission factors used to calculate annual and maximum hourly emissions for the Discoverer Americas life boat engines.

Table 3 .3

. 4

- 2

Life b oat Engine E mission Factors

Pollutant Emission Factor (g/kW

- hr) Emission Factor Basis

Total VOC 1.53 AP

- 42

NO
x 7.50 Certification

SO 2 0.007 Mass Balance

CO 5.5 Certification

PM 0.60 CertificationOuter Continental Shelf Title V and PSD Permit Application

Emission Source Description 3

- 22 ENVIRON Pollutant Emission Factor (g/kW

- hr) Emission Factor Basis

PM 10 0.49 Certification & AP

- 42

PM 2.5 0.48 Certification & AP

- 42

CO 2 e 696.60 EPA

Lead 1.23E

- 04 EPA

Benzene 3.97E

- 03 AP

- 42

Toluene 1.74E

- 03 AP

- 42

Xylenes 1.21E

- 03 AP

- 42

Formaldehyde 5.02E

- 03 AP

- 42

Acetaldehyde 3.27E

- 03 AP

- 42

Acrolein 3.94E

- 04 AP

- 42

Naphthalene 3.61E

- 04 AP

- 42

1,3

- Butadiene 1.66E

- 04 AP

- 42



### 3.3.5 Fast Rescue Boat Engines

The Discoverer Americas is equipped with one fast rescue boat. The fast rescue boat is equipped with a 212 hp (1 58 kW) engine that is operated during maintenance checks, safety exercises, or in the event of an emergency. The planned operating time for maintenance of the engine is one hour per month, which we have doubled to account for safety exercises. Since the po tential emissions of regulated air pollutants are less than 2 tpy, and HAP emissions are less than 1,000 lb/yr, the emission levels from the fast rescue boat engines are considered insignificant per 40 CFR 71.5(c)(11)(ii) and will be included as such in th e permit application forms. The table below summarizes the key operating parameters that are the basis of the potential emissions calculations for the fast rescue boat engine.

Table 3.3

. 5

- 1

Fast Rescue Boat Engine Operati ng Summary

Emissions Unit
ID Sour ce Description Maximum Power Rating (kW) Run Time

hr/month hr/yr

MOB Fast Rescue Boat Engine 158 2 12



### Below is a summary of the emission factors used to calculate annual and maximum hourly emissions for the fast rescue boat engine on the Discoverer Americas

.

Table 3.3

. 5

- 2

Fast Rescue Boat Engine Emission Factors

Pollutant Emission Factor (g/kW

- hr) Emission Factor Basis

Total VOC 1.53 AP

- 42

NO
x 7.50 Certification

SO 2 0.007 Mass BalanceOuter Continental Shelf Title V and PSD Permit Application

Emission Source Description 3

- 23 ENVIRON Pollutant Emission Factor (g/kW

- hr) Emission Factor Basis

CO 5.00 Certification

PM 0.40 Certification

PM 10 0.329 Certification & AP

- 42

PM 2.5 0.319 Certification & AP

- 42

CO 2 e 696.60 EPA

Lead 1.23E

- 04 EPA

Benzene 3.97E

- 03 AP

- 42

Toluene 1.74E

- 03 AP

- 42

Xylenes 1.21E

- 03 AP

- 42

Formaldehyde 5.02E

- 03 AP

- 42

Acetaldehyde 3.27E

- 03 AP

- 42

Acrolein 3.94E

- 04 AP

- 42

Naphthalene 3.61E

- 04 AP

- 42

1,3

- Butadiene 1.66E

- 04 AP

- 42



### 3.3.6 Heater s

The Discoverer Americas is equipped with a diesel

- fired cargo tank heater (Hot Oil Heater (Emissions Unit ID HTR)) that has a maximum heat input rate of 17.4 million British thermal

units per hour (MMBtu/hr). Th is heater heats a thermal fluid that is used to transfer heat to cargo tanks on the vessel

. Statoil does not propose to use the heater f or normal drilling operations in the Gulf of Mexico . However, the heater will require period ic maintenance testing. The planned operating time for maintenance of the heater is two hours per year. Since the potential emissions of regulated air pollutants are less than 2 tpy, and HAP emissions are less than 1,000 lb/yr, the emission levels from the fast rescue boat engines are considered insignificant per 40 CFR 71.5(c)(11)(ii) and will be included as such in the permit application

forms.

Table 3.3.6

- 1
Hot Oil Heater Operating Summary

Emissions

Unit ID Source Description Maximum Heat Input (MMBtu/hr) Run Time

hr/yr

HTR Hot Oil Heater 17.4 2



### Below is a summary of the emission factors used to calculate annual and maximum hourly

emissions for the hot oil heater located on the Discoverer Americas

.Outer Continental Shelf Title V and PSD Permit Application

Emission Source Description 3

- 24 ENVIRON 

### Table 3.3.6

- 2

Hot Oil Heater E mission Factors

Pollutant Emission Factor (lb/Mgal) Emission Factor Basis

Total VOC 0.25 AP

- 42

NO
x 20 AP

- 42

SO 2 0.2 AP

- 42

CO 5 AP

- 42

PM 3.3 AP

- 42

PM 10 1.0 AP

- 42

PM 2.5 0.3 AP

- 42

CO 2 e 22,577 EPA

Lead 1.2E

- 03 AP

- 42

Benzene 2.14E

- 04 AP

- 42

Ethyl benzene 6.36E

- 05 AP

- 42

Formaldehyde 3.30E

- 02 AP

- 42

Naphthalene 1.11E

- 03 AP

- 42

1,1,1

- Trichloroethane 2.36E

- 04 AP

- 42

Toluene 6.20E

- 03 AP

- 42

Xylene 1.09E

- 04 AP

- 42

Total PAH 1.19E

- 03 AP

- 42

Arsenic 5.5E

- 04 AP

- 42

Beryllium 4.1E

- 04 AP

- 42

Cadmium 4.1E

- 04 AP

- 42

Chromium 4.1E

- 04 AP

- 42

Mercury 4.1E

- 04 AP

- 42

Manganese 8.2E

- 04 AP

- 42

Nickel 4.1E

- 04 AP

- 42

Selenium 2.1E

- 03 AP

- 42



### 3.3.7 Storage Vessels

Emissions are generated from the storage of fuel and waste oil in tanks aboard the Discoverer

Americas . D iesel is used in the engines installed on the drilling vessel as well as the vessel’s life boat and fast rescue boat engines

. Additionally , there is a storage tank for a viation f uel,

which is used to refuel helicopters. Finally, there are two storage tanks on the drilling vessel

that are used to store waste oil that is collected from fuel system strai ners, filters, and
separators.

The EPA TANKS 4.09d computer software program was used to calculate the potential working and breathing emissions from the storage vessels located on the Developer

. The default EPA TANKS 4.09d properties for Distillate Fuel Oil No. 2 were used to calculate emissions for theOuter Continental Shelf Title V and PSD Permit Application

Emission Source Description 3

- 25 ENVIRON 

### d iesel and waste oil storage tanks

. Additionally, the default EPA TANKS 4.09d properties for Jet Naphtha were used to calculate emissions for the a viation f uel storage tanks

. For a particular storage tank, the maximum hourly emissions were estimated by dividing the annual emissions calculated for the tank using EPA TANKS 4.09d by the tank’s annual hours of

opera tion.

Since the potential emissions of regulated air pollutants are less than 2 tpy, and HAP emissions are less than 1,000 lb/yr, the emission levels from the storage tanks are considered insignificant per 40 CFR 71.5(c)(11)(ii) and will be included as su ch in the permit application forms. The table below summarizes key design and operating parameters that are the basis of the potential emissions calculations for the storage vessels.

Table 3 .3

. 7

- 1 Storage Vessel Inventory and Operating Summary

Emissions

Unit ID Source Capacity Working Capacity (gal) Throughput (gal/yr) m 3 gal

FO ST Deck 2 Fuel Oil Tank No. 1 (P) 2,591 684,470 616,023 1,150,000

Deck 2 Fuel Oil Tank No. 2 (S) 2,591 684,470 616,023 1,150,000

Overflow Fuel Oil Tank No. 1 (P) 130 34,448 31,003 575,000

FO SET ST Deck 1 Fuel Oil Tank No. 3 (P) 216 56,955 51,260 1,150,000

Deck 1 Fuel Oil Tank No. 4 (S) 216 56,955 51,260 1,150,000

FO SER ST Deck 1 Fuel Oil Tank No. 5 (P) 108 28,478 25,630 1,150,000

Deck 1 Fuel Oil Tank No. 6 (S) 108 28,478 25,630 1,150,000

FO E GEN ST Emergency G enerator Fuel Oil
Tank 16 4,095 3,685 7,000

WO ST Waste Oil Tank No. 1 (P) 35 9,299 8,369 8,369

Waste Oil Tank No. 2 (S) 62 16,299 14,669 14,669

AV ST Aviation Fuel Tank 8 2,113 1,902 9,165

FO LB ST Life b oat No. 1 Fuel Tank 0.2 45 40 22

Life b oat No. 2 Fuel Tank 0.2 45 40 22

Life b oat No. 3 Fuel Tank 0.2 45 40 22

Life b oat No. 4 Fuel Tank 0.2 45 40 22

Life b oat No. 5 Fuel Tank 0.2 45 40 22

Life b oat No. 6 Fuel Tank 0.2 45 40 22

FO MOB ST Fast Rescue Boat Fuel Tank 0.2 45 40 130



### 3.3.8 Fugitive Component s

The Discoverer Americas drill ship has fugitive emissions associated with components and associated piping to convey fuel from storage vessels to combustion units and waste oil , which

is a waste mat erial that is collected from the fuel system strainers, filters, and separators to storage vessels for proper disposal. Fugitive component counts were estimated based on a

review of the Discoverer Americas Fuel System P&IDs. Fugitive component emissions are calculated based on the component count and component service. Since potential emissions of regulated air pollutants are less than 2 tpy, and HAP emissions are less than 1,000 lb/yr, theOuter Continental Shelf Title V and PSD Permit Application

Emission Source Description 3

- 26 ENVIRON 

### emission levels from fugitive components are considere d insignificant per 40 CFR 71.5(c)(11)(ii) and will be included as such in the application forms. The table below summarizes the component counts by service on the Discoverer Americas

.

Table 3 .3

. 8

- 1 Fugitive Compon e nt Summary

Component Type Number of Fuel Service Components Number of Waste Oil Service Components

Valve 293 4

Flange 586 8
Pump Seal 11 0

Other 18 0



### T he potential emissions for the fugitive components have been calculated using the oil and gas production operations average emission factors included in Table 2

- 4 of the Protocol for Equipment Leak Emission Estimates ( EPA

- 453/R

- 95

- 017 ), November 1995 and the composition of the material to be contained or contacted by the components. Because a “heavy oil” pump

emission factor was not i dentified, we used t he “l ight o il ” pump emission factor for all of the

pumps on the drilling vessel

. For “o ther ” component types, we used the “heavy oil” emission

factor because the large majority of c omponents on the vessel are in diesel service. Finally,

Table 2

- 4 identifies separate emission factors for flanges and connectors. We conservatively used the higher of the flange and connector emission factors identified in the table to estimate emissions from the flanges/connectors located on the ves sel. The emission factors used in the potential emissions calculations for fugitive emissions are summarized in the table below.

Table 3.3

. 8

- 2 Fugitive Component Emission Factors

Service Valves (kg/hr/source) Connectors (kg/hr/source) Pumps (kg/hr/source) Other (kg/hr/source)

Diesel 8.4 E

- 06 7.5 E

- 06 1.3 E

- 02 3.2 E

- 05

Waste Oil 9.8 E

- 05 1.1 E

- 04 2.4 E

- 05 3.2 E

- 05



### 3.3.9 Support Vessels
Specific support vessels are not solely dedicated to a particular drilling campaign. Instead

, Statoil relies on a support vessel fleet made up of many different vessels that fall into one of two support vessel categories. Note that the proposed potential emissions included in this application for the Discoverer Americas support vessels will appl y to any support vessel that Statoil may use with the drilling vessel, which is expecte d to provide S tatoil with the flexibility to utilize any vessel fr om the support vessel fleet to meet project needs. Additionally, a direct physical connection between the drilling vessel and a support vessel is an unusual event. Normally, the support vessels will be under their ow n power when adjacent to the drilling vessel for loading or unloading purposes. The only expected physical connection between the drilling

v essel and a support vessel would be product transfer hoses such as those necessary for the transfer of fuel or drilling mud between the vessels

.Outer Continental Shelf Title V and PSD Permit Application

Emission Source Description 3

- 27 ENVIRON 

### To estimate annual emissions from the engines of each type of support vessel, Statoil estimated

the total hour s of operation of the particular vessel

- type during the proposed drilling campaign (180 days) based on actual hours of operation for similar vessels during historical drilling campaigns. Statoil used the actual hours of operation (with a safety buffer) in conjunction with emission factors (certification, AP

- 42, etc.) to estimate annual emissions associated with the support vessel operations. To estimate maximum hourly emissions for each support vessel type, Statoil gathered specific engine data and emissi ons information for several vessels in each category. From that information, Statoil derived the emissions that could reasonably be expected from each type of support vessel during the drilling campaign. While actual emissions will vary between different vessels, the potential support vessel emissions proposed in this application are a reasonable estimate of the emissions expected from a typical support vessel in each category.



### 3.3.9.1 Offshore Support Vessel Engines
OSVs transport personnel and supplies to and from the drilling vessel. OSVs are equipped with large engines that power generators, thrusters, and main propulsion devices . Additionally, the OSVs are equipped with small engines that are used to power emerg ency generators. Statoil used the engine inventory on the OSV Peyton Candies to represent typical engine emissions
from an OSV

.

The potential annual engine emissions from an OSV have been calculated based on the estimated annual hours of operation of eac h engine on the vessel

. Maximum hourly engine emissions from an OSV have been estimated by assuming each engine on the vessel operates at its highest load capacity for the hour. As previously noted, actual engine emissions may vary with different OSVs, b ut the potential OSV engine emissions proposed with this application are representative of a typical OSV. The table below summarizes the key operating parameters that are the basis of the potential emissions calculations for the OSV engines.

Table 3.3.9. 1

- 1 Offshore Support Vessel Engine Operating Summary

Emissions

Unit ID Source Description Maximum Power Rating (kW) Normal Operation Power Rating (kW) Normal Operation
Annual Hours (hr/yr) Maximum Hourly Power Rating (kW)

OSV OSV Main Engine No. 1 1,765 1,765 3,059 1,765

OSV Main Engine No. 2 1,765 1,765 3,059 1,765

OSV Main Engine No. 3 1,765 0 3,059 1,765

OSV Main Engine No. 4 1,765 0 3,059 1,765

OSV Emergency
Generator Engine 269 269 3,059 269



### Below is a summary of the emission factors used to calculate annual and maximum hourly emissions for the engines on the OSVs that will be associated with the Discoverer Americas

.Outer Continental Shelf Title V and PSD Permit Application

Emission Source Description 3

- 28 ENVIRON 

### Table 3.3.9.1

- 2 Offshore Support Vessel Engine Emission Factors

Pollutant Main Engine
Emission Factor (g/kW

- hr) Emergency
Generator
Emission Factor (g/kW

- hr) Emission Factor Basis

Total VOC 0.43 1.53 AP

- 42

NO x 7.20 7.20 Certification

SO 2 0.007 0.007 Mass Balance

CO 3.35 4.06 AP

- 42

PM 0.20 0.20 Certification

PM 10 0.16 0.16 Certification

PM 2.5 0.16 0.16 Certification

CO 2 e 696.60 696.60 EPA

Lead 1.23E

- 04 1.23E

- 04 EPA

Benzene 3.30E

- 03 3.97E

- 03 AP

- 42

Toluene 1.20E

- 03 1.74E

- 03 AP

- 42

Xylenes 8.22E

- 04 1.21E

- 03 AP

- 42

Formaldehyde 3.36E

- 04 5.02E

- 03 AP

- 42

Acetaldehyde 1.07E

- 04 3.27E

- 03 AP

- 42

Acrolein 3.36E

- 05 3.94E

- 04 AP

- 42

Naphthalene 5.54E

- 04 3.61E

- 04 AP

- 42

1,3

- Butadiene

-- 1.66E

- 04 AP

- 42



### 3.3.9.2 Crew B oat Engine s

The crew boats transport pe rsonnel and supplies to and from the drilling vessel. Statoil does not currently know which specific vessel or vessels will serve as a crew boat during the proposed drilling campaign. Therefore, potential crew boat engine emissions have been

estimated us ing an example of the type and size of crew boat that will be used by Statoil.

Statoil used the engine inventory on the crew boat Sybil Graham to represent typical engine emissions from a crew boat. While actual crew boat engine emissions may vary with d ifferent crew boats, the potential crew boat engine emissions proposed with this application are representative of a typical crew boat. The table below summarizes the key operating parameters that are the basis of the potential emissions calculations for the crew boat engines.Outer Continental Shelf Title V and PSD Permit Application

Emission Source Description 3

- 29 ENVIRON 

### Table 3. 3

. 9 .2

- 1 Crew Boat Engine Operating Summary

Emissions

Unit ID Source Description Maximum Power Rating (kW) Normal Operation Power Rating (kW) Normal Operation
Annual Hours (hr/yr) Maximum Hourly Power Rating (kW)

CREW Main Engine No. 1 1,342 1,342 618 1,342

Main Engine No. 2 1,342 1,342 618 1,342

Main Engine No. 3 1,342 1,342 618 1,342

Main Engine No. 4 1,342 1,342 618 1,342

Emergency Generator Engine No. 1 93 93 618 93

Emergency Generator Engine No. 2 93 93 618 93

Thruster #1 Engine 201 201 618 201

Thruster #2 Engine 201 201 618 201



### Below is a summary of the emission factors used to calculate annual and maximum hourly emissions for the engines on the crew boats that will be associated with the Discoverer

Americas

.

Table 3. 3

. 9 .2

- 2 Crew Boat Engine Emission Factors

Pollutant Large Engine
Emission Factor (g/kW

- hr) Small Engine
Emission Factor (g/kW

- hr) Emission Factor Basis

Total VOC 0.43 1.53 AP

- 42

NO x 7.20 7.20 Certification

SO 2 0.007 0.007 Mass Balance

CO 3.35 4.06 AP

- 42

PM 0.20 0.30/0.20 Certification

PM 10 0.16 0.25/0.16 Certification

PM 2.5 0.16 0.24/0.16 Certification

CO 2 e 696.60 696.60 EPA

Lead 1.23E

- 04 1.23E

- 04 EPA

Benzene 3.30E

- 03 3.97E

- 03 AP

- 42

Toluene 1.20E

- 03 1.74E

- 03 AP

- 42

Xylenes 8.22E

- 04 1.21E

- 03 AP

- 42

Formaldehyde 3.36E

- 04 5.02E

- 03 AP

- 42

Acetaldehyde 1.07E

- 04 3.27E

- 03 AP

- 42

Acrolein 3.36E

- 05 3.94E

- 04 AP

- 42

Naphthalene 5.54E

- 04 3.61E

- 04 AP

- 42

1,3

- Butadiene

-- 1.66E

- 04 AP

- 42Outer Continental Shelf Title V and PSD Permit Application

Emission Source Description 3

- 30 ENVIRON 

### 3.3.9.3 Drilling Mud
Drilling fluid (mud) is circulated between the drilling vessel and well during the drilling process to lubricate and cool the drill bit and transport drill cuttings. Additionally, the mud is needed to exert hydrostatic pressure in the well to prevent an influx of the formation’s fluids into the well

bore. When the mud is circulated from the well to the drilling vessel, it is exposed to the atmosphere and the gas entrained in the mud , which can include hydrocarbons, flashes out of the mud to the atmosphere. Emissions may come fr om any of the drilling mud equipment

, including the shaker room and mud pit/tanks. T he only appreciable hydrocarbon gases

entrained in the mud are from rock cuttings generated when the drill bit pass es through rock that is within a hydrocarbon zone. Stat oil estimates that it will only encounter one day of appreciable hydrocarbon

- containing rock per well drilled, and it is anticipated that Statoil will drill four wells during the drilling campaign. The following EPA document serves as the basis fo r the dr illing mud operations potential emissions calculations: Atmospheric Emissions from Offshore Oil and Gas Development and Production ( 450/3

- 77/026 ) , June 1977

.

Below is a summary of the operating and emission factors used to calculate annual and maximum hourly emissions for the drilling mud operations on the Discoverer Americas

. Since potential emissions of regulated air pollutants are less than 2 tpy, and HAP e missions are less than 1,000 lb/yr, the emission levels from drilling mud are considered insignificant per 40 CFR 71.5(c)(11)(ii) and will be included as such in the application forms.

Table 3. 3

. 9.3

- 1 Drilling Mud Operating Summary and Emission Factors

Po llutant Annual N umber of
Wells Drilled

(wells/yr) Emission Factor (lb/well) Emission Factor
Basis

Total VOC 4 238.18 EPA

CO 2 e 12,057.49 EPA



### 3.4 Emergency Operations

Below we discuss certain emergency operations that could occur for the two drilling vessels and the emissions to the atmosphere that would likely be related with the emergency operations. However, because these emergency operations are outside of standard operating conditions for the drilling vessels, we are not proposing to include pote ntial emissions in the permit for the operations.



### 3.4.1 Relief Wells

The need to drill a relief well to control a blowout is highly unlikely, but it is possible that a relief

well could be drilled

. The drilling of a r elief well would employ the same equipment that is used

to dr ill an exploratory well. T herefore

, all of the maximum hourly emissions shown in the tables

of this section provide hourly emissions estimates for relief well drilling activities

. No emissions

would be associated with the emer gency deployment of the BOP.

We note that EPA guidelines indicate that allowable emissions should not include emissions that would occur only as a result of events outside of standard operating conditions. TheOuter Continental Shelf Title V and PSD Permit Application

Emission Source Description 3

- 31 ENVIRON 

### following from 4 0 CFR p art 51, Appendix W in structs that emissions resulting from malfunctions

should not be factored into allowable emissions

.

Malfunctions which may result in excess emissions are not considered to be a normal operating condition. They generally should not be considered in determi ning allowable

emissions.

Emissions from emergency drilling operations, even more so than ordinary malfunctions, are highly unlikely events and should not be considered a “normal operating condition” of the drilling operation. Therefore, emergency drilling operation s are not to be factored into the allowable emissions specified by a permit.

Statoil drilling plans, protocols, and procedures contain detail s for drilling operation precautions to avoid blowouts during drilling operations. In associati on with the exploratory drilling activities proposed with this permit application, t he likelihood that a well control event would require a relief well is approximate ly 1 in 6,000. The inclusion of emissions from such an unlikely event

would be unrepresentative of “annual” emissions and inaccurate for anticipated operations.

Because emissions from drilling a relief well are so unlikely and are not reasonably foreseeable,
Statoil maintains that it is also not appropriate or practical to include s uch emissions in the emissions inventory or air quality modeling for the Developer or Discoverer Americas . In the highly unlikely event that, at some future time, the Developer or Discoverer Americas drilling operations were to cause a violation of an NAAQS or the PSD increment due to emissions produced during emergency relief well drilling at the end of a drilling season, it is acknowledged

that the EPA would have discretion to take enforcement actio n against Statoil for such a violation under the Agency’s policy on “excess emissions” that result from, inter alia, malfunctions. See “State Implementation Plans: Policy Regarding Excess Emissions During Malfunctions, Startup, and Shutdown,” Steven A. H erman, Assistant Administrator for Enforcement and Compliance (September 20, 1999) (“Herman Memorandum”). 7



### 3.4.2 Diverters

A diverter is a mechanical device located beneath the drill floor that protects drilling vessel personnel in the event an influx is not ca ught at the BOP and enters the riser. This is very rare for the type of wells being proposed since the prospective hydrocarbons are at the very deepest

section of the well. The influx for which the diverter could be used could consist of fresh or salt

wa ter, or gas. The diverter is viewed by Statoil in the same way as the BOP and both will be in place at every drilling event. It is a f ederal requirement for all drilling vessels operating in OCS waters to have a functioning diverter. As a rule, most dri lling vessels have diverters whether or not they operate in OCS waters.

7 This policy was reconfirmed in a memorandum issued by Eric Schaeffer, Director of the Office of Regulatory Enforcement, dated December 5, 2001, which clarified that the policy was intended to be applied prospectively to future SIP approvals. Although these guidance documents are designed to set out the standards under which the EPA will ap prove a SIP, they also provide the most applicable guidance to the EPA’s policy regarding excess emissions for all permits, those issued pursuant to a SIP and those issued under federal regulations.Outer Continental Shelf Title V and PSD Permit Application

Emission Source Description 3

- 32 ENVIRON 

### The diverter directs any formation fluids away from the drilling vessel in the event an influx

enter s the borehole and is not caught in time at the BOP. The diverter does not shut the well in; it merely diverts the flow for discharge away from the rig until the influx in the riser is displaced. The diverter is used because the influx may have entrained gas that would put personnel working on the rig floor at risk. The entrained gas would expand rapidly as the influx in the riser migrates to surface and could result in a rapid unloading of the well bo re at surface at the rig

floor.

The likelihood of an influx entering the riser is quite s mall for the foll owing reasons:

• Statoil conducts shallow hazards seismic surveys to delineate possible shallow gas intervals and has selected locations to avoid any likely potential shallow gas sites. Thus

, all potential hydrocarbons will be deep and wil l be caught at th e BOP.

• Statoil drills with a drilling fluid density that exceeds the anticipated formation fluid pressure. There is substantial regional data to allow prediction of the anticipated pressures from offset wells, seismic velocity and geological study. There fore

, the probability of taking in influx is small in the f irst place.

• Statoil operates the rig with instrumentation that will allow spotting influx as small as a few barrels (bbls) and in the worst case 50 bbls (in inclement weather, marine vessels

motion can preclude accurate measurement of fluid volumes). The smallest volume of
mud between the first formation drilled and the BOP after it is installed is 1

, 300 bbls. This volume would only increase as the well is deepened. The mud system that is used

disso lves any gas and the influx does not migrate upwards by itself. Therefore

, the only way an influx could get above the BOP would be that the influx is missed altogether and it is inadvertently circulated above the BOP. This is highly unlikely as the

instr umentation is automated, alarms are set, and it is monitored by the d riller, mud logger and onsho re real time operations center.

• Statoil has real

- time drill string instrumentation that permits monitoring the bottom hole pressure so that the swabbing effect can immediately be recognized and appropriate

countermeasures taken. For these reasons

, the probability of gas to surface is quite small. From an industry standpoint, in the Gulf of Mexico, in the period 1992 to 2006, 15,077 wells were drilled during w hich diverter use was documented 20 times, resulting in a probability of usage of 0.01%. Given the aforementioned precautions that will be taken in the exploration proposed with this permit application , the probability is likely substantially lower. 8



### In summary, the diverter is a safety device that would be used only in the unexpected event of

an influx into the ris er if it is not caught at the BOP. There would be emissions if the influx consisted of hydrocarbon gases, but they are unplanned and not quan tifiable.

8 Izon, David, et. al, Drilling Contractor

, Absence of fatalities in blowouts encouraging in MMS study of OCS incidents

1992

- 2006

, July/August 2007.