UNITED STATES GOVERNMENT

MEMORANDUM

December 18, 2017

To:

From:

P u b l i c I n f o r m a t i o n (MS 5030)

P l a n C o o r d i n a t o r , FO, Plans S e c t i o n (MS

5231)

Subj e c t :

C o n t r o l #

Type

Lease(s)

O p e r a t o r

D e s c r i p t i o n

R i g Type

P u b l i c I n f o r m a t i o n copy o f p l a n

R-06637

Revised E x p l o r a t i o n P l a n

OCS-G17001 B l o c k - 508 Walker Ridge Area

S h e l l O f f s h o r e I n c .

W e l l s P and Q

D r i l l s h i p o r DP Semisubmersible

A t t a c h e d i s a copy o f t h e s u b j e c t p l a n .

I t has been deemed s u b m i t t e d as o f t h i s d a t e and i s under r e v i e w f o r a p p r o v a l .

Ronald O'Connor

Pl a n C o o r d i n a t o r

S i t e Type/Name

WELL/P

WELL/Q

Botm Lse/Area/Blk Surface L o c a t i o n

G17001/WR/508 6569 FSL, 6244 FEL

G17001/WR/508 6579 FSL, 6234 FEL

S u r f Lse/Area/Blk

G17001/WR/508

G17001/WR/508

AQR Spreadsheets

COMPANY Shell Offshore Inc

AREA Walker Ridge

BLOCK 508 (Surface Location)

LEASE OCS-G 17001

PLATFORM DP MODU or Drillship

WELL P & Q

DISTANCE TO LAND 178

COMPANY CONTACT Josh O'Brien

TELEPHONE NO. 504-425-9097

REMARKS Stones-AQR-rEP-DPMODU-20171129-BOEM Submittal.xlsx

F u e l U s a g e C o n v e r s i o n F a c t o r s Natura l G a s Turb ines Natura l G a s E n g i n e s D iese l Rec ip . Eng ine R E F . D A T E F u e l U s a g e C o n v e r s i o n F a c t o r s

S C F / h p - h r | 9 .524 S C F / h p - h r | 7 .143 G A U h p - h r | 0 .0483 AP42 3.2-1 4/76 & 8/84

E q u i p m e n t / E m i s s i o n F a c t o r s un i ts P M S O x N O x V O C C O R E F . D A T E

N G Turb ines g m s / h p - h r 0 . 0 0 2 4 7 1.3 0.01 0.83 AP42 3.2-1& 3.1-1 10/96

N G 2 -cyc l e lean g m s / h p - h r 0 .00185 10.9 0 .43 1.5 AP42 3.2-1 10/96

N G 4 - c y c l e lean g m s / h p - h r 0 .00185 11.8 0.72 1.6 AP42 3.2-1 10/96

N G 4 - c y c l e r ich g m s / h p - h r 0 .00185 10 0.14 8.6 AP42 3.2-1 10/96

D iese l R e c i p . < 600 hp . g m s / h p - h r 1 0 .1835 14 1.12 3.03 AP42 3.3-1 10/96

D iese l R e c i p . > 600 hp . g m s / h p - h r 0 .32 0 .1835 11 0.33 2 .4 AP42 3.4-1 10/96

D iese l Bo i le r Ibs/bb l 0 .084 0 .3025 0.84 0 .008 0.21 AP42 1.3-12,14 9/98

N G Hea te r s /Bo i l e r s /Bu rne rs I b s / m m s c f 7.6 0 .593 100 5.5 84 '42 1.4-1, 14-2. & V 7/98

N G Flares I b s / m m s c f 0 .593 7 1 . 4 60 . 3 3 8 8 . 5 AP42 11.5-1 9/91

L iqu id F lar ing Ibs /bb l 0 .42 6 .83 2 0.01 0.21 AP42 1.3-1 & 1.3-3 9/98

Tank V a p o r s Ibs/bb l 0 .03 E&P Forum 1/93

Fug i t i \ « s I b s / h r / c o m p . 0 .0005 AR Study 12/93

G l yco l Dehyd ra to r V e n t I b s / m m s c f 6 .6 La. DEQ 1991

G a s V e n t i n g Ibs /sc f 0 .0034

S u l p h u r C o n t e n t S o u r c e V a l u e U n i t s

Fuel G a s 3.33 p p m

Per 40 CFR 80.51 OfajO), Locomotive end Marine (LM) diesel fuels are limited to 500 ppm maximum sulfur, effective June 1, 2007 D i e s e l Fue l 0.05 % w e i g h t

Per 40 CFR 80.51 OfajO), Locomotive end Marine (LM) diesel fuels are limited to 500 ppm maximum sulfur, effective June 1, 2007

P r o d u c e d G a s ( F l a r e s ) 3.33 p p m

Per 40 CFR 80.51 OfajO), Locomotive end Marine (LM) diesel fuels are limited to 500 ppm maximum sulfur, effective June 1, 2007

P r o d u c e d Oi l (L iqu id F l a r i n g ) 1 % w e i g h t

Miscellaneous Constants and Conversions

365 days/yr - Follows FLAG 2010 Guidance 2000 lb/ton conversion fector

454 g/lb conversion factor 1000 SCF/MSCF conversion fector

1.341 hp/kW con\A3rsion factor

2017 Emissions COMPANY AREA BLOCK LEASE PLATFORM WELL I CONTACT PHONE REMARKS

Shell Offshore inc Walker Rldqe i (Surface Locat OCS-G17001 P&Q j 504-425-9097 Josh O'Brien Stones-AQR-rEP-DPMODU-20171129-BOEM Submlttal.xlsx OPERATIONS EQUIPMENT RATING MAX. FUEL ACT. FUEL RUNTIME MAXIMUM POUNDS PER HOUR ESTIMATED TONS

Diesel Engines HP GAL/HR GAL/D Nat. Gas Engines HP SCF/HR SCF/D

Burners MMBTU/HR SCF/HR SCF/D HR/D DAYS PM SOx NOx VOC CO PM SOx NOx VOC CO DRILLING PRIME MOVER>600hp diesel 10728 518 4167 24 31 7.56 4.34 259.93 7.80 56.71 0.94 0.54 32.40 0.97 7.07

PRIME MOVER>600hp diesel 10728 518 4167 24 31 7.56 4.34 259.93 7.80 56.71 0.94 0.54 32.40 0.97 7.07 PRIME MOVER>600hp diesel 10728 518 4167 24 31 7.56 4.34 259.93 7.80 56.71 0.94 0.54 32.40 0.97 7.07 PRIME MOVER>600hp diesel 10728 518 4167 24 31 7.56 4.34 259.93 7.80 56.71 0.94 0.54 32.40 0.97 7.07 PRIME MOVER>600hp diesel 10728 518 4167 24 31 7.56 4.34 259.93 7.80 56.71 0.94 0.54 32.40 0.97 7.07 PRIME MOVER>600hp diesel 10728 518 4167 24 31 7.56 4.34 259.93 7.80 56.71 0.94 0.54 32.40 0.97 7.07 Energency Generator>600hp diesel 2547 123 2952 1 31 1.80 1.03 61.71 1.85 13.46 0.03 0.02 0.96 0.03 0.21 Emergency Air Compressor 600hp diesel 26 1 30 1 31 0.06 0.01 0.80 0.06 0.17 0.00 0.00 0.01 0.00 0.00 All olher rig-equipment is electric (e.g cranes) or negligible in emissions potential (e.g. life boats, welding equipment, etc.) Supply Vessel>600hp diesel (general suppo 9790 473 5674 24 31 6.90 3.96 237.20 7.12 51.75 1.28 0.74 44.12 1.32 9.63 Supply Vessel>600hp diesel (riserless suppc 9790 473 5674 24 10 6.90 3.96 237.20 7.12 51.75 0.41 0.24 14.23 0.43 3.11 Supply Vessel>600hp diesel (riserless suppc 9790 473 5674 24 10 6.90 3.96 237.20 7.12 51.75 0.41 0.24 14.23 0.43 3.11 Crew Vessel>600hp diesel 5400 261 939 24 31 3.81 2.18 130.84 3.93 28.55 0.21 0.12 7.30 0.22 1.59

YEAR TOTAL 71.73 41.11 2464.54 73.98 537.72 8.01 4.59 275.24 8.26 60.05

EXEMPTION CALCULATION

DISTANCE FROM LAND IN MILES 5927.40 5927.40 5927.40 5927.40 107586.78

178.0

Note - The MODU Campaign Average Daily Fuel Use (gal/day) is 25,000 gallons/day and represents total fuel use on the MODU. Since the Prime Movers would be the primary diesel users, the 25,000 gal/day is allocated equally amongst the six prime movers (4167 gal/day for each Prime Mover). Fuel tracking mitigations should be applied to the total MODU fuel use of 25,000 gal/day, which equates to 0.78 MMgals for 2017. The Vessel Campaign Average Daily Fuel Use (gal/day) is 6,613 gallons/day and represents total fuel use on the Support and Crew vessels, which equates to 0.32 MMgals for 2017.

2018 Emissions C O M P A N Y A R E A BLOCK LEASE P L A T F O R M W E L L CONTACT PHONE R E M A R K S

Shell Offshore Inc Walker Ridge 1 (Surface Locat OCS-G17001 P S Q 1504-425-9097 Josh O'Brien Stone&AQR-rEP-DPMODU-20171129-BOEM Submittal.xlsx

OPERATIONS EQUIPMENT RATING MAX. FUEL A C T . FUEL RUN T IME M A X I M U M POUNDS PER HOUR ESTIMATED TONS Diesel Eng ines HP GAL/HR GAL/D

Nat. Gas Eng ines HP SCF/HR SCF/D B u r n e r s MMBTU/HR SCF/HR SCF/D HR/D DAYS PM SOx NOx VOC CO PM SOx NOx VOC CO

DRILLING PRIME MOVER>600hp diesel 10728 518 4167 24 334 7.56 4.34 259.93 7.80 56.71 10.15 5.82 349.06 1 0 4 7 76.16 PRIME MOVER>600hp diesel 10728 518 4167 24 334 7.56 4.34 259.93 7.80 56.71 10.15 5.82 349.06 10.47 76.16 PRIME MOVER>600hp diesel 10728 518 4167 24 334 7.56 4.34 259.93 7.80 56.71 10.15 5.82 349.06 10.47 76.16 PRIME MOVER>600hp diesel 10728 518 4167 24 334 7.56 4.34 259.93 7.80 56.71 10.15 5.82 349.06 10.47 76.16 PRIME MOVER>600hp diesel 10728 518 4167 24 334 7.56 4.34 259.93 7.80 56.71 10.15 5.82 349.06 10.47 76.16 PRIME MOVER>600hp diesel 10728 518 4167 24 334 7.56 4.34 259.93 7.80 56.71 10.15 5.82 349.06 10.47 76.16 Energency Generator>600hp diesel 2547 123 2952 1 334 1.80 1.03 61.71 1.85 13.46 0.30 0.17 10.31 0.31 2.25 Emergency Air Compressor 600hp diesel 26 1 30 1 334 0.06 0.01 0.80 0.06 0.17 0.01 0.00 0.13 0.01 0.03 All other rig-equipment is electric (e.g cranes) or negligible in emissions potential (e.c . life boats, welding equipment, etc.)

Supply Vessel>600hp diesel (general suppo 9790 473 5674 24 334 6.90 3.96 237.20 7.12 51.75 13.83 7.93 475.35 14.26 103.71 Supply Vessel>600hp diesel (riserless supp( 9790 473 5674 24 10 6.90 3.96 237.20 7.12 51.75 0.41 0.24 14.23 0.43 3.11 Supply Vessel>600hp diesel (riserless supp( 9790 473 5674 24 10 6.90 3.96 237.20 7.12 51.75 0.41 0.24 14.23 0.43 3.11 Crew Vessel>600hp diesel 5400 261 939 24 334 3.81 2.18 130.84 3.93 28.55 2.29 1.31 78.66 2.36 17.16 Fract Boat Engines > 600hp diesel 8842 427 10250 24 100 6.23 3.57 214.23 6.43 46.74 7.48 4.29 257.08 7.71 56.09 Fract Boat - Completion Equipment > 600hp diesel

16362 790 18967 24 100 11.53 6.61 396.44 11.89 86.50 13.84 7.94 475.72 14.27 103.79

Anchor Boat for Tree/Tubing Installation > 39900 1927 46252 24 100 28.12 16.13 966.74 29.00 210.93 33.75 19.35 1160.09 34.80 253.11

2018 YEAR T O T A L 117.62 67.42 4041.94 121.30 881.88 133.25 76.40 4580.14 137.41 999.30

EXEMPTION DISTANCE FROM LAND IN MILES

C A L C U L A T I O N DISTANCE FROM LAND IN MILES

5927.40 5927.40 5927.40 5927.40 107586.78 178.0

Note - The MODU Campaign Average Daily Fuel Use (gal/day) is 25,000 gallons/day and represents total fuel use on the MODU. Since the Prime Movers would be the primary diesel users, the 25,000 gal/day is allocated equally amongst the six prime movers (4167 gal/day for each Prime Mover). Fuel tracking mitigations should be applied to the total MODU fuel use of 25,000 gal/day, which equates to 8.35 MMgals for 2018. The Vessel Campaign Average Daily Fuel Use (gal/day) is 6,613 gallons/day and represents total fuel use on the Support and Crew vessels, which equates to 2.32 MMgals for 2018.

2019 Emissions COMPANY AREA BLOCK LEASE PLATFORM WELL CONTACT PHONE REMARKS

Shell Offshore Inc Walker Ridge 508 (Surface Lc OCS-G17001 P & Q 504-425-9097 Josh O'Brien Stones-AQR-rEP-DPMODU-20171129-BOEM Submlttal.xlsx

O P E R A T I O N S E Q U I P M E N T RATING MAX. F U E L A C T . F U E L R U N T IME M A X I M U M P O U N D S PER H O U R E S T I M A T E D T O N S

D iese l E n g i n e s HP GAL /HR G A L / D

Nat . G a s E n g i n e s HP SCF /HR SCF/D

B u r n e r s M M B T U / H R SCF /HR SCF/D HR/D D A Y S PM SOx NOx V O C CO PM SOx NOx VOC CO

DRILLING PRIME MOVER>600hp diesel 10728 518 4 1 6 7 24 88 7.56 4 .34 259.93 7.80 56.71 2.68 1.53 91.97 2.76 20.07

P R I M E M O V E R > 6 0 0 h p diesel 10728 518 4 1 6 7 24 88 7.56 4 .34 259.93 7.80 56.71 2.68 1.53 91.97 2.76 20.07

P R I M E M O V E R > 6 0 0 h p diesel 10728 518 4 1 6 7 24 88 7.56 4.34 259.93 7.80 56.71 2.68 1.53 91.97 2.76 20.07

P R I M E M O V E R > 6 0 0 h p diesel 10728 518 4 1 6 7 24 88 7.56 4.34 259.93 7.80 56.71 2.68 1.53 91.97 2.76 20.07

P R I M E M O V E R > 6 0 0 h p diesel 10728 518 4 1 6 7 24 88 7.56 4 .34 259.93 7.80 56.71 2.68 1.53 91.97 2.76 20.07

P R I M E M O V E R > 6 0 0 h p diesel 10728 518 4 1 6 7 24 88 7.56 4.34 259.93 7.80 56.71 2.68 1.53 91.97 2.76 20.07

Energency Genera to r>600hp diesel 2547 123 2952 1 88 1.80 1.03 61.71 1.85 13.46 0.08 0 .05 2.72 0.08 0.59

Emergency Air C o m p r e s s o r 600hp diesel 26 1 30 1 88 0.06 0.01 0.80 0.06 0.17 0.00 0.00 0.04 0.00 0.01

All other r ig-equipment is electr ic (e.g cranes) or negligible in emiss ions potential (e.c . life boats , weld ing equ ipment , etc.)

Supply Vesse l>600hp diesel (general suppo 9790 473 5674 24 88 6.90 3.96 237.20 7.12 51.75 3.64 2.09 125.24 3.76 27.33

Supply Vesse l>600hp diesel (r iser less supp 9790 473 5674 24 10 6.90 3.96 237.20 7.12 51.75 0.41 0.24 14.23 0.43 3.11

Supply Vesse l>600hp diesel (r iser less supp 9790 473 5674 24 10 6.90 3.96 237.20 7.12 51.75 0.41 0.24 14.23 0.43 3.11

Crew Vesse l>600hp diesel 5400 261 939 24 88 3.81 2.18 130.84 3.93 28 .55 0.60 0.35 20.72 0.62 4.52

2019 Y E A R T O T A L 71.73 41.11 2464.54 73.98 537.72 21.21 12.16 728.98 21.87 159.05

E X E M P T I O N

C A L C U L A T I O N D I S T A N C E F R O M L A N D IN M I L E S

5927.40 5927.40 5927.40 5927.40 107586.78

178.0

Note - The MODU Campaign Average Daily Fuel Use (gal/day) is 25,000 gallons/day and represents total fuel use on the MODU. Since the Prime Movers would be the primary diesel users, the 25,000 gal/day is allocated equally amongst the six prime movers

(4167 gal/day for each Prime Mover). Fuel tracking mitigations should be applied to the total MODU fuel use of 25,000 gal/day, which equates to 2.20 MMgals for 2019. The Vessel Campaign Average Daily Fuel Use (gal/day) is 6,613 gallons/day and represents

total fuel use on the Support and Crew vessels, which equates to 0.70 MMgals for 2019.

COMPANY AREA BLOCK LEASE PLATFORM WELL

Shell Offshore Inc

Walker Ridge 508 (Surface Location)

OCS-G17001 DP MODU or Drillship

P & Q

Year Emitted Substance

PM SOx NOx VOC CO 2017 8.01 4.59 275.24 8.26 60.05 2018 133.25 76.40 4580.14 137.41 999.30 2019 21.21 12.16 728.98 21.87 159.05

Allowable 5927.40 5927.40 5927.40 5927.40 107586.78

Notes Emissions for MODU and Support Vessel activities from 2017 to 2019 show fuel reduction measures. They are based on historical fuels levels.

REVIS IONS TABLE:

Date of Request Plan Section What was Corrected Date Resubmitted 10/17/17 Section 1

Section 3 Section 9

Changed wells in revision Revised Geological Maps Added

10/19/17

10/31/17 Section 1 Section 9

Added Plan Reference Corrected Spill Plan References

10/31/17

SECTION 1: PLAN CONTENTS

A. DESCRIPTION, OBJECTIVES & SCHEDULE

Shell Offshore Inc. (Shell) is submitting a revised Exploration Plan (EP/Plan) for Walker Ridge (WR) 508 (OCS-G 17001). BP Exploration & Production filed the initial EP for Lease OCS-G 17001 for the drilling of wells A and B (Plan Control Number N-8155). Shell submitted a Supplemental EP for wells C and D in WR 508, which was approved by BOEMRE on May 23, 2006 (Plan Control Number S-6899), and three revised EP's for wells B, C & D (Plan Control Numbers R-4538, R-4429 and R-4309). Shell also filed supplemental plan S-7129 for wells E and F, approved November 2, 2007. Shell submitted a Supplemental EP that included three exploration wells in WR 507 and 508; wells G, H, and I (S-7514). Shell then submitted Plan S-7599 for the completion of drilled Well G (WR 507 No. 1) and the drilling and completion of new wells J, K, L, M, N, O, P and Q, approved by BOEM on April 18, 2013. Shell submitted a revised Exploration Plan for wells G, M, N, P and Q R-06455 to add a drillship which was approved by BOEM on March 24, 2016. Shell submitted Plan N-09875 Initial Exploration Plan for WR 464 and 508 to drill and complete new wells R, S, T, U, V, W, X and Y which was approved by BOEM on June 9, 2016.

: been drilled from the previous EP's:

A = API No. 608124001500 B = API No. 608124002200 E = API No. 608124003202 G = API No. 608124007700 J = API No. 608124009500 K = API No. 608124008700 L = API No. 608124009900 M = API No. 608124011000 O = API No. 608124009200 R = API No. 608124011700 S = API No. 608124010500 T = API No. 608124011200 U = API No. 608124010400 V = API No. 608124010300

w = API No. 608124011200

Shell has not drilled locations C, D, F, H, I, N, P Q, X and Y to date. At this time we are only revising Locations P 8i Q. If the wells are unsuccessful, they will be permanently plugged and abandoned in accordance with the Bureau of Safety and Environmental Enforcement (BSEE) regulations.

The drilling/completion activities are planned to commence on or about December 2017 and run approximately through March 2019 (see Attachment IC). The timeframe to complete the initial drilling/completion activities is an estimate based on the best available information regarding downhole conditions likely to be encountered while drilling each well and not intended to be a limitation. A new drill center manifold is installed to support this new production and was covered in SDOCD S-7790 approved June 9, 2016.

The lease area is 178 miles from the nearest shoreline, 193 miles from the onshore support base at Port Fourchon, Louisiana, and 221 miles from the helicopter base at Amelia, Louisiana. Water depths at the wellsites range from 9,548 to 9,558 feet (Attachment IA).

The proposed rig is either a dynamically positioned (DP) drillship or a DP semi-submersible, and both are self-contained drilling vessels with accommodations for a crew which includes quarters, galley and sanitation facilities. The rig will comply with the requirements in the BSEE Final Drilling Rules (2012). The drilling activities will be supported by the support vessels and aircraft as well as onshore support facilities as listed in Sections 14 and 15 ofthe EP. Shell has employed or contracted with trained personnel to carry out its exploration activities. Shell is committed to local hire, local contracting and local purchasing to the maximum extent possible. Shell personnel and contractors are experienced at operating in the Gulf of Mexico and are well versed in all Federal and State laws regulating operations. Shell's employees and contractors share Shell's deep commitment to operating in a safe and environmentally responsible manner.

SECTION 9: OIL SPILL INFORMATION

A. Oil Spill Response Planning

All the proposed activities and facilities in this plan will be covered by the Regional OSRP filed by Shell Offshore Inc. (0689) in accordance with 30 CFR 254.47 and NTL 2013-N02. Shell's regional OSRP was approved by BSEE in December 2014, the bi-annual review was found to be in compliance 7/7/2015, and the latest revision to the OSRP was approved 6/30/2017.

Spill Response Sites: Primary Response Equipment Locations Preplanned Staging Location(s) Ingleside, TX; Galveston, TX; Venice, LA; Ft

Jackson, LA; Harvey, LA; Stennis, MS; Pascagoula, MS; Theodore, AL; Tampa, FL

Galveston, TX; Port Fourchon; Venice, LA; Pascagoula, MS ; Mobile, AL; Tampa, FL

OSRO Information: The names ofthe oil spill removal organizations (OSRO's) under contract include Clean Gulf Associates (CGA), Marine Spill Response Company (MSRC) and Oil Spill Response Limited (OSRL). These OSRO's provide equipment and will in some cases provide trained personnel to operate their response equipment (OSRVs, etc.) and Shell also has the option to pull from their trained personnel as needed for assistance/expertise in the Command Post and in the field.

Worst Case Scenario Determination: Category Regional OSRP EP

Type of Activity1 Subsea Drilling Drilling Rig

Facility Location (area/block) MC 812 WR 508

Facility Designation2 Subsea well BO Subsea well KOO Distance to Nearest Shoreline (miles) 59 182

Volume3

Storage tanks (total) N/A N/A Flowlines (on facility) N/A N/A Pipelines N/A N/A Uncontrolled blowout (volume per day) 468,000* BOPD 47,114** BOPD Total Volume 468,000 Bbls 47,114 Bbls

Type of Oil(s) - (crude oil, condensate, Crude oil Crude oil diesel)

API Gravity(s)4 31° 28°

*24 hour rate (432,000 BOPD 30 day average) * *24 hour rate (34,632 BOPD 30 day average)

OThis well was reviewed and accepted by BOEM on in plan N-9840.

OOThis well was accepted by BOEM in Plan S-7599. All the wells in this EP were reviewed and do not exceed that WCD number.

Certification: Since Shell Offshore Inc. has the capability to respond to the appropriate worst-case spill scenario included in its regional OSRP, approved by BSEE in December 2014, the bi-annual review was found to be in compliance 7/7/2015, and the latest revision to the OSRP was approved 6/30/2017. Since the worst-case scenario determined for our Plan does not replace the appropriate worst-case scenario in our regional OSRP, I hereby certify that Shell Offshore Inc. has the capability to respond, to the maximum extent practicable, to a worst-case discharge, or a substantial threat of such a discharge, resulting from the activities proposed in our plan.

Modeling:

Shell did not model a potential oil spill or hazardous substance spill for operations proposed in this plan as it is not required per NTL 2008-G04.

Shell Offshore Inc. P. 0. Box 61933

New Orleans, LA 70161-1933 United States of America

Public Information T e l + 1 5 0 4 4 2 5 7 2 1 5

Fax +1 504 425 6747 Email Sylvia.bellone@shell.com

October 5, 2017

Ms. Michelle Picou, Section Chief Bureau of Ocean Energy Management 1201 Elmwood Park Blvd. New Orleans, LA 70123-2394

Attn: Plans Group GM 1053C

SUBJECT: Revised Exploration Plan OCS-G 17001, Walker Ridge Block 508 Unit No. 754306006 Offshore, Louisiana

Dear Ms. Picou:

In compliance with 30 CFR 550.211 and NTLs 2008-G04, 2009-G27 and 2015-N01, giving Exploration Plan guidelines. Shell Offshore Inc. (Shell) requests your approval ofthis Revised Exploration Plan (REP) to change the approved surface and bottom hole locations to drill and complete well locations P and Q. The P St, Q locations were initially approved in Exploration Plan No. S-07599 on April 18, 2013. Depending on rig availability operations could commence as early as December 1, 2017.

This Plan consists of a series of attachments describing our intended operations. The attachments we desire to be exempted from disclosure under the Freedom of Information Act are marked "Proprietary" and excluded from the Public Information Copies of this submittal. This revision affects Sections 1, 2, 3, 8 Si 9 of the previously approved EP. The attachments not included in this revision remain as previously approved.

Should you require additional information, please contact Tracy Albert at 504.425.4652 or tracy.albert@shell.com.

Sincerely,

Sylvia A. Bellone

SHELL OFFSHORE INC.

REVISED EXPLORATION PLAN

for

OCS-G 17001, Walker Ridge Block 508

Walker Ridge 508 Unit

PUBLIC INFORMATION

OCTOBER 2017

PREPARED BY:

Tracy W. Albert

Regulatory Specialist

504.425.4652

tracy.albert@shell.com

REVIS IONS TABLE:

Date of Request Plan Section What was Corrected Date Resubmitted 10/17/17 Section 1

Section 3 Section 9

Changed wells in revision Revised Geological Maps Added

SECTION 1: PLAN CONTENTS

A. DESCRIPTION. OBJECTIVES & SCHEDULE

Shell Offshore Inc. (Shell) is submitting a revised Exploration Plan (EP/Plan) for Walker Ridge (WR) 508 (OCS-G 17001). BP Exploration 8i Production filed the initial EP for Lease OCS-G 17001 for the drilling of wells A and B (Plan Control Number N-8155). Shell submitted a Supplemental EP for wells C and D in WR 508, which was approved by BOEMRE on May 23, 2006 (Plan Control Number S-6899), and three revised EP's for wells B, C 8i D (Plan Control Numbers R-4538, R-4429 and R-4309). Shell also filed supplemental plan S-7129 for wells E and F, approved November 2, 2007. Shell submitted a Supplemental EP that included three exploration wells in WR 507 and 508; wells G, H, and I (S-7515). Shell then submitted Plan S-7599 forthe completion of drilled Well G (WR 507 No. 1) and the drilling and completion of new wells J, K, L, M, N, O, P and Q, approved by BOEM on April 18, 2013. Shell submitted Plan N-09875 Initial Exploration Plan for WR 464 and 508 to drill and complete new wells R, S, T, U, V, W, X and Y.

: been drilled from the previous EP's:

A = API No. 608124001500 B = API No. 608124002200 E = API No. 608124003202 G = API No. 608124007700 J = API No. 608124009500 K = API No. 608124008700 L = API No. 608124009900 M = API No. 608124011000 O = API No. 608124009200 R = API No. 608124011700 S = API No. 608124010500 T = API No. 608124011200 U = API No. 608124010400 V = API No. 608124010300

w = API No. 608124011200

Shell has not drilled locations C, D, F, H, I, N, P Q, X and Yto date. At this time we are only revising Locations P 8i Q. If the wells are unsuccessful, they will be permanently plugged and abandoned in accordance with the Bureau of Safety and Environmental Enforcement (BSEE) regulations.

The drilling/completion activities are planned to commence on or about December 2017 and run approximately through March 2019 (see Attachment IC). The timeframe to complete the initial drilling/completion activities is an estimate based on the best available information regarding downhole conditions likely to be encountered while drilling each well and not intended to be a limitation. A new drill center manifold is installed to support this new production and was covered in SDOCD S-7790 approved June 9, 2016.

The lease area is 178 miles from the nearest shoreline, 193 miles from the onshore support base at Port Fourchon, Louisiana, and 221 miles from the helicopter base at Amelia, Louisiana. Water depths at the wellsites range from 9,548 to 9,558 feet (Attachment IA).

The proposed rig is either a dynamically positioned (DP) drillship or a DP semi-submersible, and both are self-contained drilling vessels with accommodations for a crew which includes quarters, galley and sanitation facilities. The rig will comply with the requirements in the BSEE Final Drilling Rules (2012). The drilling activities will be supported by the support vessels and aircraft as well as onshore support facilities as listed in Sections 14 and 15 ofthe EP. Shell has employed or contracted with trained personnel to carry out its exploration activities. Shell is committed to local hire, local contracting and local purchasing to the maximum extent possible. Shell personnel and contractors are experienced at operating in the Gulf of Mexico and are well versed in all Federal and State laws regulating operations. Shell's employees and contractors share Shell's deep commitment to operating in a safe and environmentally responsible manner.

Shell, through its parent and affiliate corporations, has extensive experience safely exploring for oil and gas in the Gulf of Mexico. Shell will draw upon this experience in organizing and carrying out its planned drilling program. Shell believes that the best way to manage blowouts is to prevent them from happening. Significant effort goes into the design and execution of wells and into building and maintaining staff competence. In the unlikely event of a spill. Shell's Regional OSRP is designed to contain and respond to a spill that meets or exceeds the WCD as detailed in Section 9 ofthis EP. The WCD does not take into account potential flow mitigating factors such as well bridging, obstructions in wellbore, reservoir barriers, or early intervention. We continue to invest in research and development (R&D) to improve safety and reliability of our well systems. All operations will be conducted in accordance with applicable federal and state laws, regulations, and lease and permit requirements. Shell will have trained personnel and monitoring programs in place to ensure such compliance.

B. LOCATION

See attached location plats (Attachments IA and IB) and BOEM forms (Attachments IC through IF).

C. RIG SAFETYAND POLLUTION FEATURES:

The rig to be used to drill and complete the wells in this EP will be a DP drillship (Noble Don Taylor or similar) or a DP semi-submersible (Noble Jim Day or similar) mobile offshore drilling unit (MODU). The BOP stack will be equipped with two fit-for-purpose shearing rams, one casing shear ram and one blind shear ram. Also, the rig will be equipped with a deadman/autoshear system, an acoustic backup control system, and an emergency disconnect system for disconnecting and closing the shear rams.

The rig, once selected, will comply with all of the regulations of the American Bureau of Shipping (ABS), International Maritime Organization (IMO) and the United States Coast Guard (USCG). All drilling operations will be conducted under the provisions of 30 CFR, Part 250, Subpart D, and other applicable regulations and notices, including those regarding the avoidance of potential drilling hazards and safety and pollution prevention control. Such measures as inflow detection and well control, monitoring for loss of circulation and seepage loss, and casing design will be our primary safety measures. Pollution prevention measures follow for typical rigs in Shell's fleet.

DRAIN SYSTEM POLLUTION FEATURES

Drains are provided on the rig in all spaces and on all decks where water or oil can accumulate. The drains are divided into two categories, non-contaminated and contaminated. All deck drains are fitted with a removable strainer plate to prevent debris entering the system.

Deck drainage from rainfall, rig washing, deck washing, and runoff from curbs and gutters, including drip pans and work areas, are discharged depending on if it came into contact with the contaminated or non-contaminated areas ofthe rig.

1) Non-contaminated Drains

Non-contaminated drains are designated as drains that under normal circumstances do not contain hydrocarbons, and can be discharged directly overboard. These are mostly located around the main deck and outboard in places where it is unlikely that hydrocarbons will be found.

Drains within 50 feet of a designated chemical storage area which uses the weather deck as a primary containment means shall be designated "normally plugged." An adequate number of drains around the rig shall be designated as "normally open" to allow run-off of rain water. Normally open drains shall have a plug located in a conspicuous area near the drain which can be easily installed in the event of a spill.

The rig's drain plug program consists at a minimum of a weekly check of all deck drains leading to the sea to verify that their status is as designated. If normally open they shall verify that the drain is open and that the plug is available in the area. If normally closed, they shall verify that the plug is securely installed in the drain.

In the event a leak or spill is observed, the event shall be contained (drain plug installation and/or spill kit deployment as appropriate) and reported immediately.

Rig personnel shall ensure that the perimeter kick-plates on weather decks are maintained and drain plugs are in place as needed to ensure a proper seal.

2) Contaminated Drains

Contaminated drains are designated as drains that contain hydrocarbons and cannot be discharged overboard. When oil-based mud is used for drilling it will be collected in portable tanks and sent to shore for processing.

3) Oily Water Processing

Oily water is collected in an oily water tank. It must be separated and not pumped overboard until oil content is <15 ppm. The separated oil is pumped to a dirty oil tank and has to be sent ashore for disposal. On board the MODU, an oil record log will be kept according to instructions included in the log. Any and all pollution pans are subjected to a sheen test before being pumped out. If the water passes the sheen test then it is pumped over board. If it does not pass the sheen test then the water/oil mixture is pumped to a dirty oil tank and sent to shore for disposal. All waste oil that is sent in to be disposed of is recorded in the MODU's oil log book.

All discharges will be in accordance with applicable EPA NPDES permits. See Section 18 ofthis Plan.

4) Lower Hull Bilge System

• The main bilge system is designed to drain the pontoons. There are Gould's electrically driven, self-priming centrifugal pumps - one for each main pump room. The aux pumps can be pump out with the bilge pump but has to be lined up manually from the main pump room.

• Bilge water is pumped overboard after a sheen test has been completed. • The pontoon bilge pumps are operable from the Bridge, and have audible and visual bilge alarms set for

high and low levels. • Portable submersible pumps are carried onboard the rig to service all column void spaces and are also used

for emergency bilge pump in the event of the main pump room flooding. • Alternate means of pumping the bilges in each pontoon pump room include the use of:

• The ballast system emergency bilge valve which is operated from the control panel. • Portable submersible pumps • Emergency bilge suction line connected directly to the ballast manifold. (Main Pump rooms only)

The bilge pumps are manual/automatic type pumps. They are equipped with sensors that give a high and a high-high alarm. They are set to a point at which the water gets to a certain point they will automatically turn on to pump water out in order to keep flooding under control. The pumps are also capable of being put in manual mode in which they can be turned on by hand.

5) Emergency Bilge System

Main ballast pumps may also be used for emergency bilge pumping directly from the pump rooms via remotely actuated direct bilge suction valves on the ballast system. These valves will operate in a fully flooded compartment. The ballast pumps can be supplied from the emergency switchboard.

6) Oily Water Drain/Separation System

Oily water/engine room bilge water is collected in an oily water tank. It must be separated and not pumped overboard until oil content is <15 ppm. The separated oil is pumped to a dirty oil tank and has to be sent ashore for disposal. On board all drilling units, an oil record log has to be kept according to instructions included in the log. The rig floor has two skimmer tanks and each is subjected to a sheen test before pumping overboard to ensure environmental safety. All three anchor winch windlasses have skimmer tanks and are subjected to sheen tests before discharge as well.

7) Drain, Effluent and Waste Systems

• The rig's drainage system is designed in line with our environmental and single point discharge policies. Drains are either hazardous, i.e. from a hazardous area as depicted on the Area Classification drawings, or non-hazardous drains from nonhazardous areas.

• To prevent migration of hazardous materials and flammable gas from hazardous to non-hazardous areas, the drainage systems are segregated.

• The rig's drainage system ties into oily water separators that take out elements in the drainage that could harm the environment. This is part of Noble's initiative to be good stewards ofthe environment. The oily water separators divide the drainage system into these sections:

8) Drain, Effluent and Waste Systems

• The rig's drainage system is designed in line with our environmental and single point discharge policies. Drains are either hazardous, i.e. from a hazardous area as depicted on the Area Classification drawings, or non-hazardous drains from nonhazardous areas.

• To prevent migration of hazardous materials and flammable gas from hazardous to non-hazardous areas, the drainage systems are segregated.

• The rig drainage systems tie into oily water separators that take out elements in the drainage that could harm the environment. This is part of Noble's initiative to be good stewards ofthe environment.

9) Rig Floor Drainage

The rig floor is typically outfitted with a Facet International MAS 34-3 separator. The separator has coalescent plates that remove the solids from the drainage and the remaining drainage goes to a skimmer tank. From the skimmer tank it is drained to one ofthe column dirty oil tank systems where it is then sent through 2 separators and cleaned further to reduce oil content to less than 15 ppm.

10) Columns # 3 & 4

The drains on the decks and machinery spaces are separated at mid ship and directed to either the #3 or #4 columns. The separators in these columns go through three cycles of circulation and remove oil to <15 ppm, then discharge the clean product to sea.

11) Main Engine Rooms

The engine rooms have their own drainage and handling system. The engine rooms are outfitted with a dirty oil tank and the drainage in the tank is processed through the separator, the waste from the separator goes back to the dirty oil tank and the clean water (<15 ppm) goes overboard.

12) Helideck Drains

The helideck has a dedicated drainage system around its perimeter to drain heli-fuel from a helicopter incident. The fuel can be diverted to the designated heli fuel recovery tank which is located underthe Helideck structure.

Operating configurations are as follows:

> The overboard piping valves and hydrocarbons take on valves are closed and locked. To unlock overboard or take on valves a permit has to be filled out.

> The oily water collection tank overflow valve is closed. > The drill floor drains are lined-up to the drill floor skimmer tank. The skimmer tanks have a high alarm

which sounds by means of an air horn. Before tanks are pumped out a sheen test is performed. Water is pumped out the skimmer tanks down the shunt line. The oil containment side is pumped out into 550 gal tote tanks.

> The BOP test area drains are normally lined-up to drain overboard. > The oily water separator continuously circulates the oily water collection tank. Waste oil is discharged

into the waste oil tank and oily water is re-circulated back into the oily water collection tank. Clean water is pumped overboard, which is controlled and monitored by the oil content detector, set at 15 ppm.

> The solids control system is capable of being isolated for cuttings collection. > The bilge system is normally pumped directly overboard after a sheen test has been performed. > The engine dirty oil sump can be drained down tothe Port column oily water separator which discharges

water overboard from the water side and oil is pumped out into a 550 gallon tote tank on the containment side. There is a high audible alarm on the ballast control panel.

D. Storage Tanks - Noble Don Taylor (or similar) Drillship:

Type of Storage Tank

Tank Capacity (bbls)

Number of Tanks

Total Capacity (bbls)

Fluid Gravity (Specific)

Fuel oil 2,889 4 11,556 Marine Diesel (0.91 SG) Fuel oil 3,225 4 12,900 Marine Diesel (0.91 SG) Fuel oil 2,887 4 11,548 Marine Diesel (0.91 SG) Fuel oil 2,680 4 10,720 Marine Diesel (0.91 SG) Fuel oil 178 8 1,424 Marine Diesel (0.91 SG)

Storage Tanks - Noble Jim Day DP (or similar) Semi-Submersible

Type of Storage Tank

Type of Facility

Tank Capacity

(Bbls)

Number of Tanks

Total Capacity (Bbls) Fluid Gravity (Specific)

Diesel Tank in stbd 1 80% fill in all hull tanks

Drilling Rig 3597 1

Marine Diesel (0.91 SG)

Diesel Tank in stbd 2

Drilling Rig 2713 1

Marine Diesel (0.91 SG)

Diesel Tank in stbd 3

Drilling Rig 3456 1

Marine Diesel (0.91 SG)

Diesel Tank in stbd 4

Drilling Rig 653 1

Marine Diesel (0.91 SG)

Diesel Tank in port 1

Drilling Rig 2090 1

Marine Diesel (0.91 SG)

Diesel Tank in port 2

Drilling Rig 1366 1

Marine Diesel (0.91 SG)

Diesel Tank in port 3

Drilling Rig 4787 1

Marine Diesel (0.91 SG)

Diesel Tank in port 4

Drilling Rig 3456 1

Marine Diesel (0.91 SG)

Total storage in hull tanks

Drilling Rig 22118 Marine Diesel (0.91 SG)

Diesel Settling Tanks

Drilling Rig 129 1

Marine Diesel (0.91 SG)

Diesel Settling Tanks

Drilling Rig 129 1

Marine Diesel (0.91 SG)

Diesel Settling Tanks

Drilling Rig 139 1

Marine Diesel (0.91 SG)

Diesel Settling Tanks

Drilling Rig 129 1

Marine Diesel (0.91 SG)

E. Pollution Prevention Measures

Pursuant to NTL 2008-G04 the proposed operations covered by this SEP do not require Shell to specifically address the discharges of oils and greases from the rig during rainfall or routine operations. Nevertheless, Shell has provided this information as part of its response to 1(c) above.

F. Additional Measures

> Health, safety, and environment (HSE) are the primary topics in pre-tour and pre-job safety meetings. The discussion around no harm to people or environment is a key mindset. All personnel are reminded daily to inspect work areas for safety issues as well as potential pollution issues.

> All tools that come to and from the rig have their pollution pans inspected and cleaned, and plug installation confirmed prior to leaving the dock and prior to loading on the boat.

> Preventive maintenance of rig equipment includes visual inspection of hydraulic lines and reservoirs on a routine scheduled basis.

> All pollution pans on rig are inspected daily.

> Containment dikes are installed around all oil containment, drum storage areas, fuel vents, and fuel storage tanks.

> All used oil and fuel is collected and sent to shore for recycling.

> Direct overboard drains on the rig are checked regularly to verify drain plugs are installed.

> All trash containers are checked and emptied daily, and trash containers are kept covered. Trash is collected in a compactor and shipped to shore for disposal.

> The rig is involved in a recycling program for cardboard, plastic, paper, glass, and aluminum.

> Fuel hoses are changed on an annual basis.

> Spill prevention fittings are installed on all liquid take-on hoses.

> Shell has obtained International Organization for Standardization (ISO) 14001 certification.

> Shell will use low-sulfur fuel to reduce air pollutant impacts.

Attachment IA BATHYMETRY WITH SURFACE LOCATIONS

vv

6,243,69' FEL & 6,569.26' FSL OF BLK. WR 508 X=2,369,756.3r Y=9,605,609,26'

6,233.69' FEL & 6,579.26 FSL OF BLK. WR 508 X=2,369,766.31, ¥=9,605,619.26'

8,283.00' FEL & 8,617.94' FSL OF BLK. WR 508 X=2,369,717.00' Y=9,605,657.94'

6,233.41' FEL & 6,643.89' FSL OF BLK. WR 508 X=2I369,766.59' Y=9,605,683.89'

6,250 05' FEL & 6,586.35' FSL OF BLK WR 508 X=2,369,749.95• Y=9,605,626.35'

6,190.87' FEL& 6^564.72 FSL OF BLK. WR 508 X=2,369.80913, Y=9,605,604 72'

6,372.71' FEL & 6,471.06' FSL OF BLK. WR 508 X=2,369.627.29 Y=9,605,511.06'

6,355.96' FEL & 6,531.80' FSL OF BLK. WR 508 X=2,3691644.04' ¥=9,605,571.80'

ATTACHMENT SHELL

PROPOSED SURFACE LOCATIONS EXPLORATION PLAN

SHELL, OCS-G 32690, WALKER RIDGE BLK 464 SHELL, OCS-G 17001, WALKER RIDGE BLK 508

WALKER RIDGE AREA OFFSHORE LOUISIANA

4,000 •Feel

G \30_Pro)«c<\CAD_NowOrloancVMaps\F't>rmit Flats\StonosiSton«s Proposad Surtac* Locations Exploratoo Plan NovJOM m*<J

Attachment IB - BOTTOM HOLE LOCATIONS

Omitted from PI Copies

U.S. Department of the Interior Bureau of Ocean Energy Management

Attachment 1C

O C S PLAN INFORMATION FORM

OMB Control Number: 1010-0151 OMB Approval Expires: 12/31/14

General Information

Type of OCS Plan: Exploration Plan (EP) Development Operations Coordination Document (DOCD)

Company Name: Shell Offshore Inc. BOEM Operator Number: 0689

Address: 701 Poydras St. Contact Person: Tracy Albert

New Orleans, LA 70131 Phone Number: 504.425.4652

Email Address: tracy.albert@shell.com

I f a service fee is required under 30 CFR 550.125(a) provide: Amount Paid: NA Receipt No. NA

Project and Worst C a s e Discharge (WCD) Information

Lease(s): G17001 Area: WR Block(s): 508 Project Name: Stones

Objectives(s): Oil Gas Sulphur Salt Onshore Support Base(s): Fouchon & Amelia, LA

Piatform/Well Name: Well K Total Volume of WCD: 47,114 BOPD API Gravity: 2 8 c

Distance to Closest Land (Miles): 178 Volume from uncontrolled blowout: 538 MMBO

Have you previously provided information to verify the calculations and assumptions of your WCD? X Yes No

If so, provide the Control Number of the EP or DOCD with which this information was provided S-7599

Do you propose to use new or unusual technology to conduct your activities? Yes X No Do you propose to use a vessel with anchors to install or modify a structure? Yes X No

Do you propose any facility that will serve as a host facility for deepwater subsea development? Yes X No

Description of Proposed Activit ies and Tentat ive Schedule (Mark all that apply)

Proposed Activity Start Date End Date No. of Days

Exploratory drilling See Attached Development drilling

Well completion See Attached Well test flaring (for more than 48 hours)

Installation or modification of structure

Installation of production facilities

Installation of subsea wellheads /manifold/or dry hole tree

Installation of lease term pipelines

Commence production

Other (Barge Oil Transfer)

Description of Drilling Rig Description of Structure

Jackup Drillship Caisson Tension Leg Platform

Gorilla Jackup Platform rig Fixed Platform Compliant Tower

Semisubmersible Submersible Spar Other Guyed tower

X DP Submersible Other (attached description) Floating production system Other

Drilling Rig Name (If known): Noble Don Taylor or similar, Noble Jim Day or Similar

Description of Lease Term Pipel ines

From (Facility/Area/Block) To (Facility/Area/Block) Diameter (Inches) Length (Feet)

NA

Form BOEM-0137 December 2011 - Supersedes all previous editions of this form which may not be used.)

Attachment 1D Proposed Activity Start Date End Date No. of Days

Drill and Complete Well P 12/1/2017 8/9/2018 251

Drill and Complete Well Q 8/10/2018 3/29/2019 228

Attachment 1E

Proposed Wel l /S t ructure Location

Well or Structure Name/Number (if renaming well or structure, reference previous name): P

Previously reviewed under an approved EP or DOCD? N-9875

Yes No

Is this an existing well or structure?

Yes No If this is an existing well or structure, list the Complex ID or API Number:

Do you plan to use a subsea BOP or a surface BOP on a floating facility to conduct your proposed activities? Yes No

WCD Info For wells, volume of uncontrolled Blowouts (bbls/day): 47,114 BOPD

For structures, volume of all storage and pipelines (bbls):

API Gravity of fluid

28 c

Surface Location Bottom Hole Location (for Wel ls) Completion (for multiple enter separate l ines)

Lease Number

OCS-G-17001 OCS-G 17001 OCS OCS

Area Name

Block No.

Walker Ridge Walker Ridge

508 508

Blockline Departure (in feet)

N/S Departure: 6,569' FSL N/S Departure:

N/S Departure:

E/W Departure: 6,244' FEL E/W Departure:

E/W Departure:

Lambert X-Y Coord.

X: 2,369,756 X:

Y: 9,605,609

Lat/Long Latitude : N26 0 27' 16.667" Latitude

Longitude : W 9 0 o 46' 13.522" Longitude

Water Depth (Feet): 9,591 MD (Feet) TVD (Feet)

Anchor Radius (if applicable) in feet: NA

Anchor locations for drilling rig or construct ion barge (if anchor radius is supplied above, not n e c e s s a r y )

Anchor Name or No. Area Block X Coordinate Y Coordinate Length of Anchor Chain on Seafloor

X= Y=

X= Y=

X= Y=

X= Y=

X= Y=

X= Y=

X= Y=

Attachment 1F

Proposed Well/Structure Location

Well or Structure Name/Number (if renaming well or structure, reference previous name): Q

Previously reviewed under an approved EP or DOCD? N-9875

Yes No

Is this an existing Yes X No well or structure?

If this is an existing well or structure, list the Complex ID or API Number:

Do you plan to use a subsea BOP or a surface BOP on a floating facility to conduct your proposed activities? Yes No

WCD Info For wells, volume of uncontrolled Blowouts (bbls/day): 47,114 BOPD

For structures, volume of all storage and pipelines (bbls):

API Gravity of fluid 28°

Surface Location Bottom Hole Location (for Wells) Completion (for multiple enter separate lines)

Lease Number

OCS-G-17001 OCS-G 17001 OCS

ocs Area Name

Block No.

Walker Ridge Walker Ridge Area Name

Block No. 508 508

Blockline Departure (in feet)

N/S Departure: 6,579' FSL N/S Departure:

N/S Departure:

Blockline Departure (in feet)

E/W Departure: 6,234'FEL E/W Departure:

E/W Departure:

Lambert X-Y Coord.

X: 2,369,766 X: Lambert X-Y Coord.

Y: 9,605,619 Y:

Lat/Long Latitude : N260 27" 16.764" Latitude Lat/Long

Longitude : W-90o 46' 13.410" Longitude

Water Depth (Feet): 9,591 MD (Feet) TVD (Feet)

Anchor Radius (if applicable) in feet: NA

Anchor locations for drilling rig or construction barge (if anchor radius is supplied above, not necessary)

Anchor Name or No. Area Block X Coordinate

X=

"xT

"x̂ T

"x̂ T

"x̂ T

"xT

~x̂ r

Y Coordinate

Y=

"YT

"YT

Length of Anchor Chain on Seafloor

23. Blowout Scenario

Shell submitted and BOEM accepted the WCD for WR 508 in plan S-7599, approved April 18, 2013

Uncontrolled blowout (volume first day) 47,114 BOPD

Uncontrolled blowout rate (first 30 days average daily rate) 37,318 BOPD

Duration of flow (days) based on relief well 180 Days

Total volume of spill (bbls) until relief well drilled 5.8 MMBO

SECTION 3: GEOLOGICAL AND GEOPHYSICAL

A. Geological description Omitted from PI Copies

B. Structure Contour Mapfs^ Omitted from PI Copies

C. Interpreted 2D and/or 3D Seismic linefs) Omitted from PI Copies

D. Geological Structure Cross-sectionfs^

Omitted from PI Copies

E. Shallow Hazards Report

The following reports were used for our analysis: • Gardline Surveys prepared a 3D Geohazard Assessment Walker Ridge Blocks 463-465, 506-510,

550-554, and 594-598, Volumes 1 and 2, (Report Number 6092) dated March 2004 for BP. • GEMS prepared a Wellsite Descriptions, Proposed Wellsites C 8i D, Walker Ridge 508 (Report

Number 0306-1151) dated May 2006 for Shell. • Fugro GeoConsulting, Inc. wrote an Integrated Geophysical and Geotechnical Field Development

Planning Study (Report Number 27.2009-2328) dated May 2010 for Shell. • Fugro prepared an AUV Archaeological Assessment Stones Development Area Blocks 420, 464, 508

and 552 Walker Ridge Area (Report Number 2411-1019) dated July 2011 for Shell. • C8iC Technologies prepared an Archeological Assessment Survey for Stones Development Prospect

(Report 110394) on Blocks 507, 508, 551, and 552 and vicinity in Walker Ridge Area dated August 2011 for Shell.

• C8iC Technologies (C8iC) prepared a Hazard Assessment Site Clearance and Drill Center, Blocks 507, 508, 550, 551, and 552 and Vicinity Walker Ridge, Volumes 1-3 (Number 110394) dated January 2012 for Shell.

• C8iC Technologies prepared an Archaeological, Engineering 8i Hazard Assessment Proposed 8" Gas Export Pipeline, Flowline and Umbilical Routes (Report 110394) Dated December 2011 for Shell.

• C8iC Technologies prepared a Geotechnical Laboratory Testing Data Report, Stones Export Line Survey (Report No. 110394) dated February 3, 2012 for Shell Offshore Gas Pipeline.

F. Shallow Hazards Assessment - Surface Locations previously cleared in EP N9875 approved 6/26/15. Surface Locations for P8iQ are within 500' of locations R through Y.

G. High-Resolution Seismic Lines - Surface Locations previously cleared in EP N9875 approved 6/26/15. Surface Locations for P8iQ are within 500' of locations R through Y.

H & I Stratigraphic Column with Time vs depth table Omitted from PI Copies

J . Geochemical Information This information is not required for Plans submitted in the GOM Region.

K. Future G&G Activities This information is not required for Plans submitted in the GOM Region.

Attachment 3A — Top Wilcox Thickness Structure Map

Attachment 3B - Well "P" Seismic Line

Attachment 3C - Well "Q" Seismic Line

Attachment 3D - Well "P" Cross Section

Attachment 3E - Well "Q" Cross Section

Attachment 3F — Stratigraphic Column — P

Attachment 3G — Stratigraphic Column — Q

Omitted from PI Copies.

SECTION 8: AIR EMISSIONS

A. Emissions Worksheet and Screening Questions

Screening Questions for EP's Yes No

Is any calculated Complex Total (CT) Emission amount (in tons) associated with your proposed exploration activities more than 90% of the amounts calculated using the following formulas: CT = 3400D2/3 for CO, and CT 33.3D for the other air pollutants (where D distance to shore in miles)?

X

Do your emission calculations include any emission reduction measures or modified emission factors?

X

Are your proposed exploration activities located east of 87.5° W longitude? X

Do you expect to encounter HzS at concentrations greater than 20 parts per million (ppm)?

X

Do you propose to flare or vent natural gas for more than 48 continuous hours From any proposed well?

X

Do you propose to burn produced hydrocarbon liquids? X

B. If you answer no to aM of the above screening questions from the appropriate table, provide:

(1) Summary information regarding the peak year emissions for both Plan Emissions and Complex Total Emissions, if applicable. This information is compiled on the summary form of the two sets of worksheets. You can submit either these summary forms or use the format below. You do not need to include the entire set of worksheets.

Air Pollutant

Plan Emission Amounts

(tons)

Calculated Exemption Amounts

(tons)

Calculated Complex Total

Emission Amounts

(tons) PM SOx NOx VOC CO

(2) Contact: Tracy Albert, (504) 425-4652, tracy.albert(g)shell.com

(1) Worksheets

See attached.

AQR Spreadsheets

COMPANY Shell Offshore Inc

AREA Walker Ridge

BLOCK 508 (Surface Location)

LEASE OCS-G17001

PLATFORM DP MODU or Drillship

W E L L P & Q

DISTANCE TO LAND 178

COMPANY CONTACT Josh O'Brien

TELEPHONE NO. REMARKS Stones-AQR-SEP-DPMODU-03052015.xlsx

Fuel Limit Basis for Drlllshlps and DP Semi-subs JM-10/31/14

Purpose Shell has reviewed engine information for its GOM fleet of Drillship and DP semi-sub MODUs. The single MODU with the largest power profile is the Noble Don Taylor, which has six main engines of 10,728 hp/engine. The projected fuel usages presented below would therefore be conservative across the fleet of Drillships and DP Semi-subs.

Step 1 - Determine Typical Operating Loads The Noble Don Taylor has six main engines. Historic fuel levels have been reviewed for the Noble Don Taylor and a 25,000 gallon/day fuel is a conservative fuel rate that has been utilized in previous AQRs. Fuel usage records for the Noble Don Taylor can be provided upon request.

{Step 2 - Identify Corresponding Fuel Levels Description Value Notes

PTE Fuel Use (gal/day) 74615 The Noble Don Taylor is equipped with 6 main engines at 10,728 hp each. The PTE fuel use is then estimated using the AQR conversion factor of 0.0483 gal/hp-h r

Campaign Average Daily Fuel Use (gal/day)

25,000 Daily fuel records for the Noble Don Taylor over the previous 12-month period were reviewed. In line with previous AQRs, a proposed campaign average rate of 25,000 gal/day is utilized.

CY2015 Fuel Limits MMGals 5.00 Calculated Value - Campaign Average Daily Fuel Use * Campaign Days CY2016-CY2023 Fuel Limits

MMGals 9.13 Calculated Value - Campaign Average Daily Fuel Use * Campaign Days

CY2024 Fuel Limits MMGals #REF! Calculated Value - Campaign Average Daily Fuel Use * Campaign Days

|Step 3 - Support Vessel Fuel Loads - Not Relevant - Emissions Estimated at Potential to Emit

Additional Notes 1 - Projected fuel usages are campaign specific and may change in future AQRs depending on the future fuel usage tracking. Fuel levels depicted in this AQR does not restrict Shell from using a different value in future AQRs. 2 - If tracked fuel usage associated with this activity indicates emissions may exceed the approved emissions. Shell will submit revised AQR calculations.

F u e l Usage Convers ion F a c t o r s Natural Gas Turbines Natural Gas Engines Diesel Recip. Engine REF. D A T E F u e l Usage Convers ion F a c t o r s

SCF/hp-hr | 9.524 SCF/hp-hr | 7.143 GAL/hp-hr| 0.0483 AP42 3.2-1 4/76 & 8/84

Equ ipme nt /Emiss ion F a c t o r s units PM SOx NOx V O C CO R E F . D A T E

NG Turbines gms/hp-hr 0.00247 1.3 0.01 0.83 AP42 3.2-1&3.1-1 10/96

NG 2-cycle lean gms/hp-hr 0.00185 10.9 0.43 1.5 AP42 3.2-1 10/96

NG 4-cyc le lean gms/hp-hr 0.00185 11.8 0.72 1.6 AP42 3.2-1 10/96

NG 4-cyc le rich gms/hp-hr 0.00185 10 0.14 8.6 AP42 3.2-1 10/96

Diesel Recip. < 600 hp. gms/hp-hr 1 0.1835 14 1.12 3.03 AP42 3.3-1 10/96

Diesel Recip. > 600 hp. gms/hp-hr 0.32 0.1835 11 0.33 2.4 AP42 3.4-1 10/96

Diesel Boiler Ibs/bbl 0.084 0.3025 0.84 0.008 0.21 AP42 1.3-12.14 9/98

NG Heaters/Boi lers/Burners Ibs/mmscf 7.6 0.593 100 5.5 84 42 1.4-1. 14-2, & V 7/98

NG Flares Ibs/mmscf 0.593 71.4 60.3 388.5 AP42 11.5-1 9/91

Liquid Flaring Ibs/bbl 0.42 6.83 2 0.01 0.21 AP42 1.3-1 & 1.3-3 9/98

Tank Vapors Ibs/bbl 0.03 E&P Forum 1/93

Fugit iMBs Ibs/hr /comp. 0.0005 A R Study 12/93

Glycol Dehydrator Vent Ibs /mmscf 6.6 La. DEQ 1991

Gas Vent ing Ibs/scf 0.0034

S u l p h u r Content S o u r c e V a l u e Units

Fuel Gas 3.33 ppm

D iese l Fuel 0.05 % we igh t

P roduced Gas( F lares) 3.33 p p m

P roduced Oil (Liquid Flar ing) 1 % weigh t

Per 40 CFR 80.510(a)(1), Locorrotive and Marine (LM) diesel fuels are limited to 500 ppm maximum sulfur, effective June 1, 2007

Miscel laneous Constants and Conversions

365 days/yr - Follows FLAG 2010 Guidance 2000 lb/ton conversion factor

454 g/lb conversion factor 1000 SCF/MSCF conversion factor

1.341 hp/kW conversion factor

Shell Offshore Inc Walker Ridge 'Surface Loca OCS-G17001 S, U, V, X, Y, T, W R [Jeffrey McMenii 504-425-6021 Stones-AQR-SEP-DPMODU-03052015.xlsx OPERATIONS EQUIPMENT RATING MAX. FUEL ACT. FUEL RUN TIME MAXIMUM POUNDS PER HOUR ESTIMATED TONS

Diesel Eng ines HP GAL/HR GAL/D Nat. Gas Engines HP SCF/HR SCF/D

Burners MMBTU/HR SCF/HR SCF/D HR/D DAYS PM SOx NOx VOC CO PM SOx NOx VOC CO Drilling

Support Vessels

PRIME MOVER>600hp diesel PRIME MOVER>600hp diesel PRIME MOVER>600hp diesel PRIME MOVER>600hp diesel PRIME MOVER>600hp diesel PRIME MOVER>600hp diesel Energency Generator>600hp diesd Emergency Air Compresso r 6001 All other rig-equipment is electric Supply Vessel>600hp diesel (gen^ Supply Vessel>600hp diesel (rise Supply Vessel>600hp diesel (riser] Crew Vessel>600hp diesel Fract Boat Engines > 600hp diesel

Fract Boat - Completion Equipment > 600hp diesel Anchor Boa t fo rTree /Tub ing Installation > 600hp diesel

2017-2019

10728 10728 10728 10728 10728 10728 2547

26 .g cranes) or

9440 9440 9440 5400

8842

16362

39900

518 518 518 518 518 518 123

_ 1 negligible in emissions potential (e.g. life boats, welding equipment, etc.

456 456 456 261

427

790

1927

25000

10943 10943 10943 6260

10250

18967

46252

24 24 24 24 24 24 1 1

24 24 24 24

24

24

24

365 365 365 365 365 365 365 365

365

10

110

100

100

100

7.56 7.56 7.56 7.56 7.56 7.56 1.80 0.06

6.65 6.65 6.65 3.81

6.23

11.53

28.12

116.88

4.34 4.34 4.34 4.34 4.34 4.34 1.03 0.01

3.82 3.82 3.82 2.18

3.57

6.61

16.13

259.93 259.93 259.93 259.93 259.93 259.93 61.71 0.80

228.72 228.72 228.72 130.84

214.23

396.44

966.74

7.80 7.80 7.80 7.80 7.80 7.80 I . 85 0.06

6.86 6.86 6.86 3.93

6.43

I I . 89

29.00

56.71 56.71 56.71 56.71 56.71 56.71 13.46 0.17

49.90 49.90 49.90 28.55

46.74

86.50

210.93

66.58

29.14 0.80 0.80 5.00

7.48

13.84

33.75

38.18

16.71 0.46 0.46 2.87

4.29

7.94

19.35

2288.72

1001.80 27.45 27.45 171.92

257.08

475.72

1160.09

68.66

30.05 0.82 0.82 5.16

7.71

14.27

34.80

67.00 4016.50 120.54 876.33 157.39 90.25 5410.23 162.31

499.36

218.58 5.99 5.99

37.51

56.09

103.79

253.11

1180.41

EXEMPTION CALCULATION

DISTANCE FROM LAND IN MILES 5927.40 5927.40 5927.40 5927.40 178.0

107586.78

NOTE - Emissions for MODU act iv i t ies are not es t imated at the Potent ia l to Emit as emiss ion reduc t ion measures (pro jec ted fue l usage levels) have been u t i l i zed . A l l suppor t vessel act iv i ty are es t imated at the Potent ia l to Emi

COMPANY AREA BLOCK LEASE PLATFORM WELL

Shell Offshore Inc

Walker Ridge

508 (Surface Location)

OCS-G17001 DP MODU or Drillship

Year Emitted Substance

PM SOx NOx VOC CO AQR Emissions if DP MODU (Semi-sub or Drillship) is Utilized

CY2017-CY2019 157.39 90.25 5410.23 162.31 1180.41

Allowable 5927.40 5927.40 5927.40 5927.40 107586.78

Notes 1. Emissions include fuel reduction measures on the MODU. All other activity is estimated at the

Potential to Emit.

SECTION 9: OIL SPILL INFORMATION

A. Oil Spill Response Planning

All the proposed activities and facilities in this EP will be covered by the Regional OSRP filed by Shell Offshore Inc. (0689) in accordance with 30 CFR 550 and 254. Shell's Regional OSRP was approved by BSEE on April 11, 2013 and modified November 17, 2014. The Bi-Annual OSRP was submitted to BSEE on February 24, 2015 and is pending approval.

Spill Response Sites: Primary Response Equipment Locations Preplanned Staging Location(s) Fourchon, LA; Cameron, LA; Houma, LA; Lake

Charles, LA Lake Charles, LA ; Cameron, LA ; Fourchon ; LA

The names ofthe oil spill removal organizations (OSRO's) under contract include Clean Gulf Associates (CGA), Marine Spill Response Company (MSRC), Clean Caribbean America (CCA), and OSRL/EARL.

Worst Case Scenario Determination: Category Regional OSRP EP

Type of Activity1 Subsea Drilling Drilling Rig

Facility Location (area/block) MC 812 WR 508 Facility Designation2 Subsea well 30 Subsea well

Distance to Nearest Shoreline (miles) 59 182

Volume3

Storage tanks (total) N/A N/A Flowlines (on facility) N/A N/A Pipelines N/A N/A Uncontrolled blowout (volume per day) 468.000* BOPD 47.114*** BOPD Total Volume 468,000 Bbls 47,114 Bbls Type of Oil(s) - (crude oil, condensate. Crude oil Crude oil diesel) API Gravity(s)4 31° 28°

*24 hour rate (432,000 BOPD 30 day average) * *24 hour rate (34,632 BOPD 30 day average)

OThis well was reviewed and accepted by BOEM on in plan N-9840.

OOThis well was accepted by BOEM in Plan S-7599. All the wells in this EP were reviewed and do not exceed that WCD number.

Since Shell Offshore Inc. has the capability to respond to the appropriate worst-case spill scenario included in its regional OSRP, approved by BSEE on April 11, 2013 and modified November 17, 2014. The Bi-Annual OSRP was submitted February 24, 2015, and since the worst-case scenario determined for our Plan does not replace the appropriate worst-case scenario in our regional OSRP (approved and pending), I hereby certify that Shell Offshore Inc. has the capability to respond, to the maximum extent practicable, to a worst-case discharge, or a substantial threat of such a discharge, resulting from the activities proposed in our EP.

Modeling:

Shell did not model a potential oil spill or hazardous substance spill for operations proposed in this plan as it is not required per NTL 2008-G04.