Ps Williams.

August 2, 2017

U. S. Department of the Interior Bureau of Safety and Environmental Enforcement Gulf of Mexico OCS Region 1201 Elmwood Park Boulevard New Orleans, LA 70123-2394

WILLIAMS FIELD SERVICES -GULF COAST COMPANY, L.P. 2800 Post Oak Boulevard P 0. Box 1396 Houston, Texas 77056 Phone; (713) 215-2000 Fax: (713) 215-3535

R E C E I V E D AU6 03 2017

Office of Field Operations Pipdine Section

Attention: Ms. Angle Gobert Pipeline Section Chief

RE: Right-of-Way No. OCS-G29358, Pipeline Segment No. 19708, a Proposed 16-inch Gas Right-of-

Way Pipeline, Located in Main Pass Block 261, OCS Federal Waters, Gulf of Mexico, Offshore,

Louisiana and Alabama

Ms. Gobert:

By letter dated April 21, 2017, the Bureau of Safety and Environmental Enforcement approved and application from Williams Field Services - Gulf Coast Company, L.P. (Williams) for right-of-way (ROW) No. OCS-G29358, Pipeline Segment No. (PSN) 19708, a 16-inch gas pipeline approximately 460 feet in length to be installed in Main Pass Block 261, OCS Federal Waters, Gulf of Mexico, Offshore, Louisiana and Alabama.

Williams hereby requests an alternate compliance for approval to hydrotest the interconnection spool onshore. The spool will be hydrotested to the applicable hydrotest pressure onshore, installed and leak tested offshore prior to interconnecting to Shell 16-inch pipeline (PSN 19659). In support of this request, attached is a Pressure Test Summary Table for PSN 19708.

Should you have questions or require additional information, please contact Cathy Thornton at (713) 705-8020 cathv.thornton@williams.com or Chelsea Rice at (713) 215-3529 Chelsea.rice(S)williams.com.

Sincerely,

Cathy Thornton Offshore Regulatory Compliance Specialist, Sr.

CAT Enclosure

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16-in Pipeline System Pressure Test Summary Table (PSN 19708)

Schematic

Section ID System Component Description Design Pressure

Hvdro-Test Test

Duration

(hr)

Hydro-Test Location Offshore - Eost Interconnection

Leak Test at MAOP , 5 e e s t e p 3 i n n o t e 5 )

Leak Test

Duration

(hr)

Maxium Operating

Pressure of Pipeline

Section

(PSN 19708)

Schematic

Section ID System Component Description Design Pressure Pressure

(psig)

Test

Duration

(hr)

Hydro-Test Location Offshore - Eost Interconnection

Leak Test at MAOP , 5 e e s t e p 3 i n n o t e 5 )

Leak Test

Duration

(hr)

Maxium Operating

Pressure of Pipeline

Section

(PSN 19708)

1 16-in Norphlet Subsea Spool Segment Riser Spools ANSI 1500#pressure class 4113 8 Offshore-Post Installation

3750 2 3750 2 16-in Norphlet Subseas Spool Segement Topside Riser Sections ANSI 1500# pressure class 4113 4 Onshore - Fabrication Yard

3750 2 3750 3 16-in Norphlet Subsea Spool Segment Pig Receiver Skid ANSI 1500# pressure class 4113 4 Onshore - Fabrication Yard

3750 2 3750

4 16-in Norphlet Subsea Spool Interconnection Spools ANSI 1500# pressure class 4113 4 Onshore - Fabrication Yard

3750 2 3750

5 Shell's 16-in Norphlet Pipeline (PSN 16659) ANSI 900# pressure class Shell 16-in Norphlet Pipeline (PSN iggsg ) 1 ! - ^ 1 1 ^^ 5 ^

Notes: 1 The 16-in interconnection spool will be hydrotested onshore, installed and leak tested offshore prior to interconnecting these to the Shell 16-in Pipeline (PSN 19659).

The testing sequence of the system is as follows:

1) The 16-in Riser has been hydrotest offshore to the stated pressure

2) The 16-in subseas Spools near MP-261A will be fabricated, onshore, tested onshore prior to their offshore installation. 3) Once installed, a leak test to verify the integrity of the flanged connections will be conducted which includes the 16-in topside pig-launcher, 16-in topside piping, 16-in riser and 16-in subsea spools at MP-261A.

4) The system will be left flooded until such time that the Shell 16-in pipeline is ready to be tested/commissioned.

5) Shell's 16-in Norphlet pre-commissioning includes hydrotesting the pipeline to including the subsea spools, riser and topside piping to the pipeline pressure test at 1.25-MAOP.

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16- in Norp l i leT SL. te*» Spoot S^gnoem Riser Spoo ls

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16-in Pipeline System Pressure Test Summary Table (PSN 19708)

Schematic

Section ID System Component Description Design Pressure

Hvdro-Test

Pressure

(BSiE)

Test

Duration

(hr)

Hydro-Test Location Offshore - Post Interconnection

Leak Test at M A O p ( ' « « « P " " " « " I

Leak Test

Duration

(hr)

Maxium Operating

Pressure of Pipeline

Section

(PSN 19708)

1 16-in Riser ANSI 1500# pressure class 5557 8 Offshore - Post Installation

3705 2 3705 2 16-in Topside Piping (from top of Riser to Pig-Launcher Skid tie-in) ANSI ISOOK pressure class 5557 4 Onshore - Fabrication Yard

3705 2 3705 3 16-in Topside Pig LauncherSkid ANSI 1500# pressure class 5557 4 Onshore - Fabrication Yard

3705 2 3705

4 16-in Subsea Spools near MP-261A ANSI 15000 pressure class 5557 4 Onshore - Fabrication Yard

3705 2 3705

5 16-in Pipeline ANSI SKKW pressure class Shell 16-in Norphlet Pipeline (PSN 19659)

Notes; 1 The 16-in interconnection spool will be hydrotested onshore, installed and leak tested offshore prior to interconnecting these to the Shell 16-in Pipeline (PSN 19659)

The testing sequence of the system is as follows: 1) The 16-in Riser has been hydrotest offshore to the stated pressure

2) The 16-in subseas Spools near MP-261A will be fabricated, onshore, tested onshore prior to their offshore installation 3) Once installed, a leak test to verify the integrity of the flanged connections will be conducted which includes the 16-in topside pig-launcher. 16-in topside piping, 15-in riser and 16-m subsea spools at MP-251A 4) The system will be left flooded until such time that the Shell 16-in pipeline is ready to be tested/commissioned 5) Shell's 16-in Norphlet pre-commissioning includes hydrotesting the pipeline to including the subsea spools, riser and topside piping to the pipeline pressure test at 1.25-MAOP