hd12 013 10 st re 3022 1 a 10 cathodic protection design report

8/10/2019 HD12 013 10 ST RE 3022 1 a 10 Cathodic Protection Design Report

1/10

Petroamazonas

Amistad 10 Cathodic Protection Design Report

Document Number HD12-013-10-ST-RE-3022

Document Revision 1

Document Status Approval

Document Type Analysis & Design Report

Originator / Author M&H/T-Rex Engineering & Construction, L.C.

Issued Date April 29, 2013

Security ClassificationCONFIDENTIALThe document is T-Rex ConfidentialUnauthorized disclosure or redistribution is not permitted

Disclosure

Texas Engineering FirmNumber

F - 11318

Revision History as shown

next page


2/10

Amistad 10

Cathodic Protection

Design ReportDoc. No.: HD12-013-10-ST-RE-3022-R 1 Date: April 29, 2013

File Name: HD12-013-10-ST-RE-3022-1-Amistad 10 Cathodic Protection Design Report Page 2 of 10

Revision History

Rev Date Issued Description Revised By Approved By

0 4/22/2013 Final Report GRL/M&H Gary A. Sidwell, P.E.

1 4/29/2013 Final Report with OFFGOSAcomments

FM Melquis Rivas


3/10

Amistad 10

Cathodic Protection



TABLE OF CONTENTS

1.0 GENERAL..................................................................................................................... 4

2.0

DESIGN CRITERIA....................................................................................................... 4

2.1

Design Life...................................................................................................................... 4

2.2

Design Current Densities................................................................................................. 4

2.3 Anode Data..................................................................................................................... 4

2.4

Surface Area................................................................................................................... 5

2.5

Initial Anode Current Output.......................................................................................... 7

2.6

Final Anode Current Output........................................................................................... 8

2.7

Anode Current Requirement........................................................................................... 9

2.8 Anode Quantity..............................................................................................................10

2.9

Anode Placement............................................................................................................10


4/10

Amistad 10

Cathodic Protection



1.0 GENERAL

Supplementary to the design basis report for Amistad-10, this report details the design ofthe cathodic protection system using 725 pound (net) Galvalum III Aluminum anodes.

2.0 DESIGN CRITERIA

The design criteria used to determine the anode requirements are presented below.

2.1 Design Life

The design life for the offshore platform is 30 years.

2.2 Design Current Densities

Current Density(mA/ft2)

Initial (mA/ft2) Mean (mA/ft2) Final (mA/ft2) Basis

Seawater 14 8 9 Table A1,NACE RP0176for U.S. West

Coast

Mud 2 2 2 Typically Used

2.3 Anode Data

The design of the cathodic protection system was based in the use of 725 pound (net)Galvalum III Aluminum anodes. Product Data is shown herein.


5/10

Amistad 10

Cathodic Protection



2.4 Surface Area

The design of the cathodic protection system is based on the surface area of the jacketstructure and conductors, including appurtenances, above the mudline and the surfacearea of the piles and conductors below the mudline. The combination of these surfaceareas determines the anode requirement for the platform.


6/10

Amistad 10

Cathodic Protection




7/10

Amistad 10

Cathodic Protection



2.5 Initial Anode Current Output

The initial anode current output was calculated using the following formulas:

Edriving_force 0.25V

resitivity 9. 449ohm in (Reference NACE Table A1 for U.S. West Coas

k 0 .159 0 (Dimensional constant)

Linitial_anode 98in

Canode_perimeter 38. 01 3in

rinitial_anode

Canode_perimeter

2 6.05in

Rresistance

resitivityk ln4 Linitial_anode

rinitial_anode

1

Linitial_anode

0.049ohm

Iinitial_current

Edriving_force

Rresistance

5.142A


8/10

Amistad 10

Cathodic Protection



2.6 Final Anode Current Output

The final anode current output was calculated using the following formulas:

futilization 0.90 utilization factor

Minitial_anode 725lb initial anode weight (mass)

Mfinal_anode Minitial_anode 1 futilization 72.5lb final anode weight

Lfinal_anode

Linitial_anode

1futilization

10

89.18in

Adensity 0.0998lb

in3

density of anode

Dpipe_core 4.5in outside diameter of a 4-in schedule pipe

Apc

Dpipe_core2

415.904in

2 cross sectional area of pipe core

Acs_final

Mfinal_anode

Adensity Lfinal_anode 8.146in2

Atotal_cs_anode Acs_final Apc 24.05in2

wanode Atotal_cs_anode 4.904in final anode width

rfinal_anode 4wanode

2 3.122in final anode radius

Rrequired_resistance

resitivityk ln4 Lfinal_anode

rfinal_anode

1

Lfinal_anode

0.063ohm

Irequired_current

Edriving_force

Rrequired_resistance

3.969A


9/10

Amistad 10

Cathodic Protection



2.7 Anode Current Requirement

The anode current requirement was calculated using the following formulas:

Iinitial 14mA

ft2

Imean 8m A

ft2

Ifinal 9m A

ft2

Imud 2m A

ft2

Iwells 3.00A

nwells 4

Aabove_mudline 14977ft2

Abelow_mudline 128 01ft2

Irequired_initial

Aabove_mudlineIinitial Abelow_mud line Imud 1000

235.28mA

Irequired_mean

Aabove_mudlineImean Abelow_mudli ne Imud 1000

145.418mA

Irequired_final

Aabove_mudlineIfinal Abelow_mud line Imud 1000

160.395mA

Irequired_wells Iwellsnwells 12A


10/10

Amistad 10

Cathodic Protection



2.8 Anode Quantity

The total anode quantity of 49 was calculated using the following formulas:

manode 725lb

tdesign 30yr

Urate 1150A hr

lb

Q1

Irequired_initial1000

Iinitial_current

45.754

Q2

Irequired_mean tdesign 1000

Urate manode 45.867

Q3

Irequired_final 1000

Irequired_current

40.416

Qwells

Irequired_wells tdesign

Urate manode 3.785

Qtotal trunc Q2 round Qwells 49

2.9 Anode Placement

The placement of the anodes on the jacket structure was determined by minimizing theglobal effect on the center of gravity of the jacket structure and an even distribution overthe height of the jacket structure.

hd12 013 10 st re 3022 1 a 10 cathodic protection design report

Documents