Design Considerations Mexico Subsea Pipelines Design_Considerations_Mexico...2018/10/15 · NORSOK R-001 Mechanical Equipment NORSOK R-001. Rev. 3, Nov. 1997. ANSI/API 12A Oil storage

DNV GL © 2017 15 October 2018 SAFER, SMARTER, GREENERDNV GL © 2017

15 October 2018

DNV GL

Design Considerations – Mexico Subsea Pipelines

1

Mexican Regulations, DNV GL Services

DNV GL © 2017 15 October 2018

PIPELINE DESIGN CONSIDERATIONS

Agenda

2

24 October, 2018

I DNV GL IN MEXICO OVERVIEW1

MEXICAN INSTITUTIONAL FRAMEWORK2

REGULATORY OVERVIEW MEXICO, PIPELINES 3

DNV GL SUPPORT FOR REGULATORY REQUIREMENTS, PIPELINE SERVICES4

5

QUESTIONS6



DNV GL in Mexico

4

20+ years in Mexico

100+ local employees

4 Local Offices with head office in Mexico City

Multi-discipline Team

Working in collaboration with ASEA, CRE,

SEMARNAT (PROFEPA) in the process of creation

of various regulations

Good relationship with SENER (Energy Minister),

CRE, CNH, ASEA, SEMARNAT (PROFEPA)

Authorized by Regulators to provide verification in

accordance with multiple National Standards


DNV GL Mexico Accreditations

5

Statutory Verification Before the opening of the upstream Oil & Gas sector and ASEA creation, the

authorities in Mexico used a statutory verification scheme to achieve compliance

with the different national standards required by the regulators, (i.e. SENER, CRE,

SEMARNAT, STPS…).

DNV GL in Mexico is authorized by the regulators to provide verification of the

below national standards:

Natural Gas Facilities:

• NOM-001-SECRE

• NOM-002-SECRE

• NOM-003-SECRE

• NOM-007-SECRE

• NOM-013-SECRE

Pressure Vessels:

• NOM-020-STPS

Electrical Facilities:

• NOM-001-SEDE-2005

LPG Facilities:

• NOM-015-SECRE

• NOM-004-SECRE



Mexican Regulatory Institutions

7

Regulations

SEMARNAT – Ministry of Environment

SHCP – Ministry of Finances and Taxes

SCT – Ministry of Transportation

STPS – Ministry of Labour

SENER – Ministry of Energy

CENACE – Energy Control Center

CENAGAS – Natural Gas Regulatory

PEMEX – National Oil Company

CFE – Enterprise State Company for

Power, Transmission and Electrical

Distribution

CRE – Regulator for Non- Hydrocarbon

Energy

CNH – Regulatory for Hydrocarbon E&P

ASEA – Regulator for HSE

Decentralized

Entities

Enterprise

State

Companies

Regulatory

Bodies

Ministries


DNV GL Mexico – Current Regulatory Authorizations (new scheme)

▪ Authorized by ASEA to perform Probabilistic Economical Damage for Loss

of Well Control (Only party to be authorized)

▪ Authorized by ASEA to provide Certification of elements of SASISOPA (Only

international company to be authorized)

▪ Authorized by ASEA to perform Third Party Services for Upstream

▪ Under approval by ASEA to perform Audits of the performance of the

SASISOPA

▪ In dialogue with CNH for 3rd party approval for Well Certification

8



Mexico Field Development Typical Timeline – Licensing and Approvals

10

Winner

Exploration Plan

Transition

Phase

180 Days

CNH

Approval

Initial Exploration

Period

Notification

CNH

Discovery

Notice

120 Days

120 Days 4 Years 30 Days

Evaluation

Plan

(Drilling)

180 Days

CNH

Approval

60 Days

Evaluation

Activities

3 Years

Commercial

Discovery

Development

Plan

90 Days 2 Years

Commercial

Notification

120 Days

CNH

Approval

34 Years 35 Years

Production

Final Transition

Phase

1.° Additional Exploration Period (3 Years)

2° Additional Exploration Period (3 Years)

5 Years 10 Years

First Extension

Phase

Second Extension

Phase

(SASISOPA

EBL

SIE)

Activity / Phase

Owner / Operator

Activity

Approval / Notification

by Regulator


Regulations and Governance Roles for Project Phases

11

Winner

Exploration Plan Production

SASISOPA

Environmental

Baseline

Social Impact

Evaluation

E&E

DEVELOPMENT

PLANS

Initial Exploration

Period

DRILLING WELL

REGULATION

RESERVOIR

QUANTIFICATION

HYDROCARBONS

METERING

Development

Plan

EXPLOITATION OF

NATURAL GAS

Insurance E&E Incidents &

Accidents notice

Incidents &

Accidents RCA

SURFACE RECOGNITION,

E&E OF HC SASISOPA

Winner


Regulatory Framework for Floaters in Mexico – DNV GL Interpretation

12

Process Plant:

Risk Based Verification

(DNVGL-SE-0474)

Studies for ALARP:

HAZID, EERA, FERA, QRA Noise,

Well release and Spill (CFD), etc.

Hull, Mooring & Marine

Systems:

Class Notation + Statutory

ASEA

Regulatory

Compliance

As if PROD+Existing NOMs/

Applicability

(e.g. Pressure vessels,

Electrical, Lifting appliances

,Metering, discharge

+


Typical Standards included in ASEA E&E RegulationsNORSOK N-006, 2nd

Edition, 2015Assessment of structural integrity for existing offshore load-bearing structures. NORSOK N-006, Second Edition, April 2015.

Equipment and Materials

API 14A Specification for Subsurface Safety Valve Equipment. Twelfth Edition, January 2015.

ANSI/API 6A Specification for Wellhead and Christmas Tree Equipment, Twentieth Edition October 2010.

API 6AV1 Specification for Validation of Wellhead Surface Safety Valves and Underwater Safety Valves for Offshore Service. Second Edition, February 2013.

API 53 Standard, Blowout Prevention Equipment Systems for Drilling Wells. Fourth Edition, November 2012.

NFPA31 Standard for the Installation of Oil-Burning Equipment. Edition 2016.

NORSOK M-001 Materials Section. Fifth Edition, September 2014.

NORSOK M-501 Surface preparation and protective coating. Sixth Edition, February 2012.

NORSOK R-001 Mechanical Equipment NORSOK R-001. Rev. 3, Nov. 1997.

ANSI/API 12A Oil storage tanks with riveted shells.

ANSI/API 14B Recommended practices. Design, Installation, Operation, Test, and Redress of Subsurface Safety Valve Systems.

Personnel

NORSOK S-006 HSE Evaluation of contractors. Rev. 2, Dec. 2003.

Pipelines

API RP 1111 Design, Construction, Operation, and Maintenance of Offshore Hydrocarbon Pipelines (Limited Status), Fourth Edition, August 2007.

ASME B31.4-2012 Pipeline Transportation Systems for Liquids and Slurries, ASME for Pipe Pressurization, B31, November 2012.

ASME B31.8-2014 Transmission and Distribution Piping Systems, ASME for Pipe Pressurization, September 2014.

ISO 15589-2 Petroleum, petrochemical and natural gas industries — Cathodic protection of pipeline transportation systems – Part 2: Offshore Pipelines, 2012.

NORSOK M-503 Cathodic protection. Rev. 3, May 2007.

Production Operations

NORSOK I-106 Fiscal metering systems for hydrocarbon liquid and gas, First Edition, November 2014.

NORSOK U-001 Subsea production system. Fourth Edition, October 2015.

NORSOK S-003 Environmental care. Rev. 3, Dec. 2005.

Safety Management Systems

ABS Change Management for Maritime and Offshore Industries, February 2013.

API RP 75 Recommended Practice for Development of a Safety and Environmental Management Program for Offshore Operations and Facilities. Third Edition, May 2004.

DNV-OSS-300 DNV GL, Risk-Based Verification, April 2012 and associated series of standards (301,302,304,306 and 307)

NORSOK P-002 Process System Design. First Edition, August 2014.

NORSOK S-001 Technical Safety. Fourth Edition, February 2008.

13


What do we have today?

14

• All Mexican offshore pipelines were designed, built

and operated by Pemex PEP

• Offshore production in Mexico started ca. 40 years

ago

• The pipeline network grew with the development of

new fields and the extension of existing ones

• There are oil, gas and N2-lines

• The lines are not regulated (yet) and remain

property of Pemex

• New pipeline capacity will have to be constructed

by the new operators, which will be regulated


MEXICO ENERGY REFORM: THE TRANSFORMATION

15


New Mexican Revolution

16

• Rising Energy demand in Mexico

• Inexpensive, abundant US shale gas

• Drive to cleaner energy generation

• Falling gas production of Pemex

5 year plan for to:

• Double the length from 10k to 20k kms

• Private investment of 10 BUSD

• Anchored by CFE contracts

• First private offshore pipeline

• US Gas Exports 2016: 3.7 B$ / 4 BCFD


Energy Reform 2013 – opening & reform

17

Round 1.4, Deepwater

Round 1.1, shallow

▪ The Energy Reform ended 75 years of

a Pemex Monopoly in Hydrocarbon

activities

▪ We have had six license rounds for

onshore, shallow- and deep water

fields that overall were considered

successful

▪ 70% award rate/ 39 contracts/ 26

contractors/ 14 countries/ 49 BUSD

expected investment

▪ New Operators: Statoil, DEA, CNOOC,

Chevron, Total, Murphy, BHP Billiton,

PC Carigali, ENI, ..

▪ New Regulators were established


New Institutional Environment

18


New Regulatory Structure

19


CRE – ASEA: Who is responsible for what?

▪ Regulates the midstream sector

from a commercial perspective

▪ Issues and enforces the

compliance with relevant

Regulations (NOMs, DACGs)

▪ Issues and validates Transport

permits, et al

▪ Regulates and administers the

open access to transport capacity

▪ Sets Tariffs: Transport, Distr.,

Storage

▪ Oversees Metering activities

20

▪ Regulates the Hydrocarbons

Sector related to Industrial

Safety and Protection of the

Environment

▪ Issues Licenses to Operators

▪ Requires the implementation and

upkeep of a SASISOPA (sim.

SEMS) for all operators

▪ Issues and enforces the

compliance with relevant

Regulations (NOMs, DACGs)

▪ Accident investigations (RCA)


Mexican Regulations for Subsea Pipelines

▪ There are NO dedicated Subsea Pipeline Regulations in Mexico at this

point in time!!

▪ For gas pipelines CRE and ASEA require compliance with the NOM-007-SECRE-

2010, which was based originally on ASME-B31.8, and does not address subsea

pipeline specific items.

▪ NOM-007 does not reference directly any International subsea pipeline code.

▪ ASEA has issued Upstream regulations and in Art. 73 they require that Pipelines

need to be designed, installed and maintained in a way that industrial- and

operational safety is ensured and the environment protected.

▪ ASEA refers to API-RP-1111 as one of the obligatory standards listed in Annex 1

of the Upstream regulations.

21


Mexico Offshore Development Summary

▪ Mexico has initiated a comprehensive Energy Reform and is

opening up the complete hydrocarbons sector

▪ Gas demand in Mexico is expected to grow another 30% over

the next 10 years, more pipelines will be necessary

▪ An important part of the reform is a redesign of the regulatory

environment, including the establishment of new regulators and

re-defining existing ones.

▪ De-coupling of commercial and Safety & Environmental aspects

and responsibilities

▪ Authorities regulating offshore pipelines are CRE and ASEA

▪ Currently and for the near future there are no specific

Offshore Pipeline Regulations, what is used are NOMs

coupled with international regulations (API, DNV GL, etc.)

22


Mexico Natural Gas

23


Codes and Standards-CFE

24

The Natural Gas Transmission System and the Carrier must

comply with the following:

The General Law of Ecological Balance and Environmental

Protection (Ley General de Equilibrio Ecológico y la

Protección al Ambiente, LGEEPA) and its Regulations

pertaining to the Ecological Code, Environmental Impact

Assessment, Prevention and Control of Pollution to the

Atmosphere, Pollution from Noise Emissions, and Protected

Natural Areas.

Law on the Coordinated Regulatory Agencies in Energy

Matters.

Hydrocarbons Law and its Regulations.

Regulations of the Activities Referred to in Title III of the

Hydrocarbons Law

Federal Electricity Commission Law and its Regulations.

Federal Law on Metrology and Standardization.

NOM-001-SECRE-2010. NG Specifications;

NOM-007-SECRE-2010. NG Transmission.

NOM-008-SECRE-1999. External Corrosion control

NACE Standards

ASME Standards

ASTM Publications

API

• NOM-007-SECRE-2010.

• NOM-001-SECRE-2010.


On-Shore: CFE Requirements- UV Gas Specification (NOM-001)

25

Summary:

1. Document review and Inspection (materials and

components in evaluation of Natural Gas spec).

2. Verify Testing methods & ensure they are duly

validated

3. Traceability

4. Equipment calibrations and capability of personnel

5. Documentation delivered by the manufacturer

6. Procedure for installation, operation and

maintenance

7. Results of testing and control statistics

8. Field verification to ensure verified procedures are

applied.


NOM-007 (2010)7.1.2 In the pipeline design must consider aspects such as:

a) Physical and chemical characteristics of natural gas, according to NOM-

001-SECRE-2010, natural gas Specifications

b) Maximum operating pressure, and

c) Maximum operating temperature.

7.2 Additional loads. a) live loads such as the weight of natural gas

(consider the weight of water to effect the calculation), snow, ice and wind,

among others;

b) charges for cyclical vehicle traffic;

c) dead loads such as the weight of the pipe, coatings, fillers, valves and

other accessories not supported;

d) stresses caused by earthquakes;

e) Vibration and / or resonance;

f) Efforts settlements or landslides caused by unstable soils in regions;

g) effects of thermal expansion and contraction;

h) Movement of equipment connected to the pipeline;

i) Efforts caused by river currents or storm;

j) Efforts caused at intersections with roads;

k) safety factor for population density (F), in accordance with paragraph

7.10 of this Standard;

l) Factor joint efficiency (E), in accordance with paragraph 7.11 of this

Standard;

m) additional thickness by natural wear or corrosion margin.

26

HydroTest:A 1.25 times the MPOP location for class 1 and1.5 times the MPOP location for classes 2, 3 and 4.

Class Location based on No. of buildings and Occupancy

Class location Design factor (F)

1 0.72

2 0.60

3 0.50

4 0.40

Table 2. Factor design by population density

Change in class location. Study required. When an increase in population density it will cause a possible change in class location and should conduct a study to determine register:


On-Shore: CFE Requirements- NOM-007

27

Summary:

1. Accredited and approved person

2. In the absence of official Mexican standard or

Mexican standard applicable =International

standards

3. Document review and Inspection (materials

and components in evaluation of Natural Gas

spec).

4. Develop Verification program consistent with

Construction/ operation.

5. Document Review

✓ Design

✓ Materials and Equipment

✓ Construction and Testing

✓ Operation and Maintenance Safety

6. On-shore pipeline


PIPELINE REGULATIONS

28

On-Shore Off-Shore

Mexico USA Mexico USA

CFE, CRE

Article 134 of

Political

Constitution

Hydro-Carbon Law

Articles 2 Section

III, 4 Section XVII

and XXXVIII, 48,

50, 51, 52, 60,

65-75, 90, 123

TITLE 49—TransportationSubtitle B—OTHER REGULATIONS RELATING TO TRANSPORTATION (CONTINUED)CHAPTER I—PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED)SUBCHAPTER D—PIPELINE SAFETYPART 192—TRANSPORTATION OF NATURAL AND OTHER GAS BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS

None

BSEE & DOT

(30 CFR

250, 30 CFR

192)

Regulatory

Requirements

http://www.ecfr.gov/cgi-bin/text-idx?SID=b3c2a23c3f78368b0bcac237ef4f73af&mc=true&tpl=/ecfrbrowse/Title49/49tab_02.tpl

http://www.ecfr.gov/cgi-bin/text-idx?SID=b3c2a23c3f78368b0bcac237ef4f73af&mc=true&tpl=/ecfrbrowse/Title49/49subtitleB.tpl

http://www.ecfr.gov/cgi-bin/text-idx?SID=b3c2a23c3f78368b0bcac237ef4f73af&mc=true&tpl=/ecfrbrowse/Title49/49chapterI.tpl

http://www.ecfr.gov/cgi-bin/text-idx?SID=b3c2a23c3f78368b0bcac237ef4f73af&mc=true&tpl=/ecfrbrowse/Title49/49CIsubchapD.tpl

http://www.ecfr.gov/cgi-bin/text-idx?SID=b3c2a23c3f78368b0bcac237ef4f73af&mc=true&node=pt49.3.192&rgn=div5


DNV GL service specification (DNV-OSS-301)

31

Verification Plan for offshore PipelineWhy• To give industry guidance for developing a certification or verification plan

covering all phases of new development projects based on many years of best practice in the industry

Identifying and ranking critical elements What• Guidance for identifying and ranking critical elements of the project and

prioritising verification activities accordingly.

• Describing verification process and the activities for each of the project phases.

• Detailed scope of work tables for all phases (except operation) and all level of involvement.


Offshore Codes & Standards

▪ DNV OSS 301 Verification and Certification of

Submarine Pipelines

▪ DNV-OS-F101 Submarine Pipeline System

▪ DNV-RP-F101 Corroded Pipelines

▪ DNV-RP-F102 Pipeline Field Joint Coating

▪ DNV-RP-F103 Cathodic Protection

▪ DNV-RP-F105 Free Spanning Pipelines

▪ DNV-RP-F106 Pipeline Coatings

▪ DNV-RP-F107 Pipeline Protection

▪ DNV-RP-F108 Fracture Control

▪ DNV-RP-F109 On-Bottom Stability

▪ DNV-RP-F110 Global Buckling

▪ DNV-RP-F111 Trawling

▪ DNV-RP-F113 Pipeline Subsea Repair

▪ DNV-RP-F116 Subsea Pipeline System Integrity

32

Frame agreement specifications

ProjectDesign premise

Auth.Rules & Reg.

Selected standards (ISO, Norsok, DNV,

API, ASME etc.)

Operation &Maint. Req's

Functional andTechnical Req's

Authorities

Operator

Standards

API 1111 - Design, Construction,

Operation and Maintenance of Offshore

Hydrocarbon Pipelines

ISO 13623 - Petroleum and natural gas

industries – Pipeline transportation

systems.

ASME B31.8 - Gas Transmission and Distribution Piping Systems


Integrated services across the entire Pipeline life cycle

RISK MANAGEMENT ADVISORY

STRATEGYFEASIBILITY &

CONCEPT SELECTION

DESIGN

CONSTRUCTION

INSTALLATION &

COMMISSIONING

OPERATION & LIFE

EXTENTION

DECOMMIS-SIONING

TECHNICAL ADVISORY

TECHNICAL ASSURANCE (Certification, Verification & Inspection)

NOBLE DEBNTON MARINE ASSURANCE & ADVISORY

OFFSHORE CLASSIFICATION

65%65% of the world’s offshore pipelines are designed and installed to DNV’ GLs pipeline standard

DNV GL Capabilities


Offshore Pipelines US GOMEX

34

Project References


DNV GL Mexico Office Experience (Pipelines)

35

+20 yearsin Mexico

DNV GL MX Office have

earned more than $31.00

MUSD with services related

to pipelines.

Customers

+ 100 different customersPEMEX, GDC, Ienova, ICA Fluor, TAG pipelines, ENGIE, etc.

Experience.Team with more than +200 years in local and technical knowledge

RegulatorsParticipate as invited members for the creations of several Mexican Norms. Good relationship with CRE, ASEA and SENER

Local Offices+ 150 colleagues

4 offices (Mexico City, Villahermosa, Queretaro and Ciudad del Carmen)

860 km pipeline from US to the Centre of Mexico up to 2.1 bcfNatural Gas

DNV GL Mexico was involved in different services in the biggest pipeline ever constructed in Mexico

• PIMS Implementation Phase II South

• Verification Services (UV) Phase I

• Inspection Services for steel plate and pipeline for Phase II

• Verification Services (UV) Phase II North

Los Ramones I and II


Mexico Main Pipeline Projects

36

Date of Assignation

Client Scope of Work Pipeline Service Location

2014-oct-02 IEPI MéxicoInspection / Certification Services of material

of line pipeLos Ramones Fase II North and

SouthInspection / Certification Services Mexico/China

2014-dic-16 ICA FLUOR, S. DE R.L. DE C.V. Implementation of PIMs Los Ramones Fase II RBI / AIM / GaliomSan Luis Potosi -

Queretaro -Guanajuato

2014-jun-25Gasoductos de Chihuahua, S. de

R.L. de C.V.Implementation of RBI with Galiom

(Technical Advisory + Galiom)Several GDC pipelines and

compression stationsRBI / AIM / Galiom Cd. de México

2006- mar-03 Green Energy Supervision, inspection and Quality ControlEl Sauz - San Miguel de Allende,

GtoVerification Unit Natural Gas Queretaro

2015-feb-03Gasoductos de Chihuahua, S de

R.L. de C.V.Verification Services for the Transport

SystemLos Ramones Fase I Verification Unit Natural Gas Various

DNV GL © 2017 15 October 201837


Key Pipeline Design Considerations

▪ Pipeline routing, survey & Geotechnical

▪ Wall thickness

▪ On-bottom Stability

▪ Fatigue

– VIV & Allowable Free Span

▪ Pipeline Thermal Expansion Analysis

▪ Bottom roughness

▪ Pipeline Installation

▪ Flow Assurance

▪ Shore approach design & River Traffic

38


Regulatory Codes & Standards

39

Regulatory

NOM-007-SCRE-2010NOM-001-SECRE- 2009

Transport of Natural Gas (Mexican Standard)Specifications of Natural Gas (Mexican Standard)

American Society of Mechanical Engineers

ASME B31.8 Gas Transmission and Distribution Piping Systems

American Petroleum Institute

API RP 1111Design, Construction, Operation and Maintenance of Offshore Hydrocarbon Pipelines (Limit State Design)

API Spec 5L Specification for Line Pipe

DNV

DNV-OS-F101 Submarine Pipeline Systems

DNV-RP-F103 Recommended Practice for Cathodic Protection of Submarine Pipelines by Galvanic Anodes

DNV-RP-F105 Recommended Practice for Free Spanning Pipelines

ISO

ISO 15589-2Petroleum, petrochemical and natural gas industries – Cathodic protection of pipeline transportation systems – Part 2: Offshore pipelines


Code Allowables: API, ASME, DNV

40

DNV


Wall Thickness Calculation Check

41

Wall thickness criteria

▪ Burst Design

– ASME B31.8, para. 841.1.1 (same as 49 CFR 192.105)

– API RP 1111, section 4.3.1.1

– DNV OS-F101, pressure containment

▪ Collapse design

– API RP 2RD, Section 5.4, Hydrostatic Collapse

– API RP 1111, Collapse due to External Pressure

– API RP 1111, Buckling due to Combined Bending and External

Pressure

– DNV OS-F101, Collapse due to external pressure, local buckling


Pipeline On-bottom Stability

42

▪ Driving Forces

– Inertia forces from the waves

– Drag Forces from wave and current

▪ Resisting or Restoring Forces

– Soil interaction and friction

– Passive resistance due to penetration


Research Philosophies

43

▪ American Gas Association A.G.A program

– Hydrodynamic tests performed at DHI in Denmark, key authors

V. Jacobsen et.al

– AGA software that determines stability of pipeline based the

ability of pipeline to resist movement from a given storm build-

up

▪ DNV-RP-F109

– PIPESTAB, Esso Norge, Statoil & SINTEF, key authors R Verley

et.al

– DNV GL Stablelines, PONDUS

– Determines pipeline resistance based on absolute (no pipeline

movement) and generalized stability (allowing certain

displacement e.g. L = 5* D or 10 D)


Soil resistance

44

▪ Sand

– Small dependency on density (except for sand with high

calcium carbonate)

– Lower bound coefficient of friction = 0.6

▪ Clay

– Strong dependency on density and shear strength,

su ranges from 500 Pa (thick black water) to 70,000 PA (stiff

Teflon)

– Lower bound coefficient of friction = 0.2


Lateral Stability – How to obtain stable pipe

45

▪ Steel weight, higher WT increases the weight

– rsteel = 7950 kg/m3

– But adds to cost

▪ Concrete coating, used to increase weight

– Density: 1900-3400 kg/m3 but

– Increases diameter (and loads) 40 -120 mm

▪ Partially or fully bury the pipe

▪ Trenching

▪ Restrain the pipe e.g. using piles or rock berns

– Be aware of overloading (moment/strain) & fatigue


Pipeline Fatigue

46

• Strong tidal and bottom current

• Seabed conditions are very dynamic

• Scouring produces span gaps of less

than a foot

• DNV RP F105 provides guidance for

allowable span lengths to mitigate

VIV


Allowable Free Span Length

▪ Allowable span length calculation is based on DNV RP

F105

▪ Allowable span length criteria:

– Screen fatigue;

– Fatigue

– Response model (VIV inline and cross flow)

– Force model (wave induced fatigue)

– ULS (strength, local buckling)

47

▪ The designer’s calculation results were assessed with DNV software – FatFree, and

the results showed reasonable comparison.


Soil Springs

▪ Soil springs maybe developed using the following methods

– Clay: American Lifeline Alliance (ALA 7/2001);

– Sand: DNV RP F105, DNV RP F109, DNV RP F110;

– Large Displacement: R. Verley, ASME-OMAE 1995;

▪ Vertical: linear or non-linear springs can be used in analysis

▪ Axial and Lateral: Effective frictions are generally developed based

on submerged weight of the pipe under different conditions, as one

of the contact properties in FE model;

48


Bottom Roughness

▪ Bottom roughness analysis (FEA) is carried out to serve the

following purpose:

– Identify free spans under different phase (location and

length);

– Identify high stresses in the pipeline due to bottom

roughness;

– Check if there is any global buckling issues;

▪ Finite Element models reflects:

– Pipe structure and submerged weight;

– Realistic material curve

– Seabed roughness;

– Pipe-soil contact (vertical stiffness, axial and lateral frictions);

– Pipeline conditions (as-laid, flooded, hydrotest, and operation)

with pressure and temperature profile;

49


Thermal Expansion

50

▪ Pipeline Expansion

– Temperature: temperature differential with

as-laid condition;

– Pressure

– End cap effect due to pressure differential

(position);

– Poisson effect due to pressure differential

(negative);

▪ Pipeline expansion analysis was considered

with:

– FE method (non-linear soil friction, global

buckling, seabed roughness etc. can be

considered, more accurate);

– Subsea Tie-ins


Pipeline Installation


Pipeline Flow Assurance (FA)

▪ Flow Assurance shall consider the following parameters

– Pipeline elevation profile

– Hydrate management strategy

– Gas composition, temperature & pressure conditions for steady state and transient

conditions

– FA to support commissioning, N2 displacement, initial startup conditions

▪ Steady state and Transient FA calculations typically use OLGA & PipeSim

software programs

52


The appropriate method shall meet technical

and environmental issues beyond the

management aspects of costs and schedules.

• Severe environmental conditions.

• High dynamic and interaction between

waves, currents and sediment

transportation.

• Site investigation, installation design

and operation difficulties.

• Pipeline on-bottom stability throughout

the design life, concrete coating.

• Environmental issues and regulations,

buried pipeline, etc.

Near Shore challenges


Pipeline other Design Issues

▪ Cathodic Protection & Internal Corrosion

▪ Inspection, Repair & Maintenance

▪ Integrity Management

54


SAFER, SMARTER, GREENER

www.dnvgl.com

Questions

55

Documents

Design Considerations Mexico Subsea Pipelines Design_Considerations_Mexico...2018/10/15 · NORSOK R-001 Mechanical Equipment NORSOK R-001. Rev. 3, Nov. 1997. ANSI/API 12A Oil storage