Service

Subsea Pipeline Design

Subsea and nearshore pipeline design to DNV-ST-F101: route selection, wall thickness and material grade, on-bottom stability (DNV-RP-F109), free-span and VIV fatigue (DNV-RP-F105), expansion and lateral buckling, shore approaches and HDD crossings, and installation analysis for S-lay and J-lay. Delivered from Mumbai for operators, EPCs and pipe-lay contractors.

What you receive

Route study and constraints mapping; crossing and approach concepts
Wall thickness, material and coating design (DNV-ST-F101, ASME B31.4/B31.8, API 5L)
On-bottom stability (DNV-RP-F109), free-span screening and VIV fatigue (DNV-RP-F105)
Expansion, upheaval and lateral buckling assessment; end-expansion and spool design inputs
HDD shore-crossing design: pull-back loads, curvature, casing and coating checks
Installation analysis (OFFPIPE / OrcaFlex): S-lay and J-lay stresses, A&R, pre-commissioning

Design basis first

A pipeline is designed twice if the design basis is loose. We fix the product, pressure and temperature profiles, the survey data and the installation vessel before any calculation, then run the DNV-ST-F101 limit states in order: pressure containment, collapse and propagation, on-bottom stability, free spans, global buckling and installation. The output is a design report with the load cases and utilisations a verifier can check line by line.

Shore approaches and HDD crossings

Landfalls decide schedule risk. We compare open-cut, cofferdam and HDD options on geotechnical data and consenting constraints, and design HDD crossings from entry and exit angles through pull-back loads and pipe stresses. Our HDD crossing guide in the insights section sets out the method.

Where we have worked

Nearshore pipeline works on India’s west coast and pipe-lay vessel engineering for a piggyback pipeline installation in Nigeria. The pipeline team also delivers cryogenic and LNG piping stress for terminals, so onshore and offshore piping interfaces sit with one team.

Codes & standards

DNV-ST-F101DNV-RP-F109DNV-RP-F105DNV-RP-F110ASME B31.4 / B31.8API 5LBS 7910

Software

OFFPIPEOrcaFlexAutoPIPECAESAR IIAbaqusPLAXISANSYS

Systems

Export & infield pipelinesPiggyback linesRisers & spoolsUmbilicals & cablesShore crossings

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Projects that prove it

Pipelay vessel upgrade — piggyback pipeline installationTwo-phase engineering to modify an operating pipelay vessel for piggyback pipeline installation — from technical feasibility and modification concept to detailed engineering.

Related services

Riser & Conductor Installation EngineeringInstallation engineering for risers and conductors on fixed platforms: clamp and guide design, lift and running procedures, vessel interface, fatigue during installation and the MWS-ready calculation package. Our team engineered a four-platform riser campaign with sixteen lifts, assessed feasibility for more than thirty riser lifts, and supervised conductor installation at Mumbai High for 120+ offshore days.FSRU & LNG Terminal Engineering with Cryogenic PipingEngineering for FSRU conversions and LNG import terminals: regasification and hull interface structure, jetty berthing and mooring analysis, cryogenic piping design and stress analysis to ASME B31.3, and class and IGC Code compliance. Cryogenic piping is a capability few boutique consultancies hold, and it lets us take an FSRU or terminal scope from marine structure to the regas manifold.Third-Party Verification & Independent Design ReviewIndependent verification of offshore structural, naval architecture and pipeline engineering: design reviews, re-analysis with our own models, structural integrity assessments and owner’s-engineer review of contractor deliverables. Our team has reviewed five jackets and topsides for an operator and assessed 39 ONGC jacket structures, and supports jack-up site assessments in ONGC, ADNOC and Aramco fields.

Regions we serve for this

Offshore, Marine & Pipeline Engineering in IndiaKannamwar Engineering is headquartered in Mumbai and delivers offshore structural, naval architecture and pipeline engineering to operators, EPC contractors and yards across India: ONGC’s western offshore fields, HPCL’s marine terminals, west-coast LNG infrastructure and the east-coast basins. 39 ONGC jacket structures assessed, riser and conductor installation campaigns engineered, and 120+ days of offshore site supervision at Mumbai High.Offshore & Marine Engineering Support for Nigeria and West AfricaEngineering support for vessel owners, installation contractors and terminal developers in Nigeria, Ghana, Angola and the wider Gulf of Guinea: vessel upgrades and deck-equipment installation, pipe-lay and installation engineering, class approval packages and design review. Our team has delivered a pipe-lay vessel piggyback pipeline upgrade and a four-davit installation on vessels operating in Nigeria.Offshore Engineering Support for the Gulf: UAE, Saudi Arabia, Qatar, Oman, KuwaitEngineering support for EPC, T&I and fabrication contractors and jack-up operators working in the Arabian Gulf: jacket and topside engineering, sea-fastening and load-out packages, lifting engineering, jack-up site-specific assessment support and third-party design review, delivered from Mumbai in the same working day. Saudi Aramco and Lamprell are among our clients.

Sectors

Subsea Pipelines, Cables & SURF Offshore Oil & Gas Ports, Coastal & Marine Infrastructure

Disciplines

Pipeline, Riser & Subsea

Frequently asked questions

Which pipeline design code do you use?

DNV-ST-F101 for subsea pipelines with the DNV recommended practices (F109 on-bottom stability, F105 free spans, F110 global buckling); ASME B31.4/B31.8 where the client or regulator requires it.

Do you do the installation analysis as well as the design?

Yes. S-lay and J-lay stress and strain analysis, abandonment and recovery, and pre-commissioning are delivered in OFFPIPE and OrcaFlex alongside the design.