Industries
Upstream, midstream and downstream engineering — skids, vessels, piping and process structures for operators and EPCs.
Quick answer
Structural Engineering Services supports Oil & Gas projects worldwide with skid package design, pressure vessel design, pipe stress analysis, pipe rack design — delivered by senior engineers on licensed software to international codes.
Governing codes
Sector challenges
Upstream, midstream and downstream packages share one problem: equipment, piping and steel are engineered by different people on different schedules, and the gaps surface in the fabrication shop. These are the four we design against most often.
Challenge 01
H2S, high design pressures and cyclic operation push shell thickness, flange rating and material selection well past standard practice.
How we answer it
Material and hardness selection to NACE MR0175 / ISO 15156, thickness and flange checks in PV-Elite, with PWHT and hardness requirements written onto the fabrication drawings rather than left to the shop.
Challenge 02
Hot process lines grow against rigid nozzles and rack steel, overloading equipment connections long before the pipe itself is in trouble.
How we answer it
Every stress-critical line is modelled in CAESAR II, nozzle loads are compared against WRC 107/297 and vendor allowables, and supports or expansion loops are re-engineered until they pass.
Challenge 03
Packages are built far from site, so road, barge and crane envelopes constrain the design before process does.
How we answer it
Shipping envelope, centre of gravity and lift points are fixed at concept stage, and the skid frame is designed for the transport and lifting cases, not only for the in-place condition.
Challenge 04
Shell DEPs, Saudi Aramco SAES, ADNOC and company standards override the base code in ways that are easy to miss when bidding.
How we answer it
Specifications are read into a project-specific design basis and checked clause by clause at internal review, so client comments come back on content, not on compliance.
Relevant services
Engineering complete modular skids — vessels, piping, structure, lifting and foundations.
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Designing separators, drums, reactors and columns to ASME, EN or PD codes.
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Checking piping systems for sustained, thermal and occasional loads, nozzle loads and support reactions.
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Analysing and detailing main and secondary pipe racks with pipe, thermal, wind and seismic loads.
ExploreTypical assets
From a single assembly to a complete package — the asset types our oil & gas teams work on week to week.
Two- and three-phase separators, slug catchers and knock-out drums to ASME VIII Div 1 and 2.
Metering, manifold, chemical injection and test skids complete with frame, piping and lifting design.
Main and secondary racks carrying thermal, friction, wind and seismic pipe loads.
Drums, scrubbers, absorbers and fractionation columns with skirt, saddle and nozzle design.
Pump, compressor and exchanger supports with vibration limits and maintenance access.
Plot plan and routing through to isometrics, supports and full stress analysis.
Codes & specifications
The base code is only half the story. On oil & gas work the client specification usually overrides it somewhere, so we agree a single reconciled design basis before any calculation starts.
Browse all codesProcess piping: wall thickness, allowable stress range and flexibility for every hydrocarbon line.
Vessel construction, with Div 2 used where thickness or cyclic duty makes design-by-analysis cheaper.
Atmospheric and low-pressure storage attached to the facility.
Sour service limits that govern welding, hardness and PWHT, not just material grade.
Structural steel for racks, platforms and skid frames; RP 2A where the package is offshore-bound.
Flange ratings at the package boundary, where most interface disputes start.
Free quote
Send the drawings or datasheets you already have. We will tell you what is missing and quote the scope in 24 hours.
Project lifecycle
Most clients bring us in at detailed design. We can start earlier, or pick a package up mid-stream — here is what you get from us at each stage.
Options, preliminary sizing and budget tonnage, before the scheme is frozen.
Facility layout, equipment count and preliminary weights for the AFE estimate.
You receive
Design basis, load schedules and layouts good enough to price and procure from.
Line list, equipment datasheets and skid footprints frozen so vendors can quote.
You receive
Full analysis, code checks, 3D modelling and issued-for-construction documentation.
Vessel code calculations, stress-critical line analysis and rack steel issued for construction.
You receive
Shop queries, RFIs and as-built updates while steel is being cut and erected.
Shop queries on nozzle orientation, weld detail and PWHT closed inside the working day.
You receive
Deliverables & handover
Oil and gas packages ship with a manufacturing data book index agreed up front, so calculations, drawings and material summaries drop straight into the MDR your client signs off.
| Deliverable | Format | Issued at |
|---|---|---|
| Design basis and calculation report | PDF, signed and checked | Detailed design |
| General arrangement drawings | DWG + PDF | FEED to detailed design |
| Drawing register and transmittal | XLSX + PDF | Every issue |
| Package GA with shipping envelope | DWG + PDF | FEED to detailed design |
| Lifting, transport and foundation load data | PDF calculation + XLSX load table | Detailed design |
| Mechanical design calculations | PV-Elite output + PDF with code references | Detailed design |
| Fabrication and nozzle orientation drawings | DWG + PDF | Pre-fabrication |
| 3D piping model and isometrics | Native + PDF/DWG, line-numbered | Detailed design |
| Stress report with support and nozzle loads | PDF + CAESAR II .c2 input | Detailed design |
| Tekla 3D model | Native .db1 + IFC 2x3/4 | Detailed design |
| Single-part, assembly and erection drawings | PDF + DWG, one sheet per mark | Detailed design |
| CNC files, bolt list and BOQ | NC1/DSTV, DXF, XLSX | Pre-fabrication |
| Nozzle load and WRC local stress check | PDF calculation per nozzle | Detailed design |
| Hazardous area and fireproofing limit mark-ups | DWG + PDF | Detailed design |
Two-stage check
Originator, then senior checker signs off every sheet before it leaves our office.
Native files included
You own the model, so another team can pick the work up at any point.
Revision control
A revision table on every sheet; superseded issues are archived, never deleted.
Your transmittal route
Issued through your document-control portal with your numbering, or over secure FTP.
Directory
Jump straight to the market you build in. Every page sets out the governing codes, units and delivery window we work to there.
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Start your project
Free, no-obligation proposal from a senior engineer.