Project Engineering in Oil & Gas – FEED, Detailed Design & Interface Management

Welcome to the Project Engineering section of Engineer’s Notebook. This page is your go-to resource for understanding the core functions, processes, and coordination tasks involved in engineering projects within the oil & gas and petrochemical industries. Whether you’re managing FEED, detailed design, or multi-discipline engineering interfaces, this section provides a comprehensive guide to support successful project execution.

What is Project Engineering?

Project engineering involves planning, coordinating, and delivering technical engineering tasks across all stages of a project lifecycle. It ensures that all discipline-specific engineering outputs align with overall project goals, timelines, and regulatory requirements.

Front End Engineering Design (FEED)

Front End Engineering Design (FEED) is the critical first phase in any large-scale oil & gas or industrial engineering project. It involves high-level planning and preliminary design before the actual detailed engineering begins.

Objectives of FEED:

  • Define technical requirements and project scope
  • Develop preliminary engineering deliverables
  • Prepare capital cost estimates
  • Identify potential risks and mitigation plans
  • Create project schedules and execution strategies

Key FEED Deliverables:

  • Process Flow Diagrams (PFDs)
  • Piping and Instrumentation Diagrams (P&IDs)
  • Equipment lists and process datasheets
  • Design philosophies and specifications
  • Plot plans and layout drawings

A well-executed FEED phase minimizes scope changes and cost overruns during execution. FEED engineering also forms the technical foundation for bidding and contractor selection.

Detailed Engineering in Oil & Gas Projects

Detailed engineering begins once the FEED phase is complete. It involves the development of final, construction-ready documents and drawings that drive procurement, construction, commissioning, and operation.

Discipline-wise Breakdown:

  • Process Engineering – PFDs, P&IDs, H&MB, line lists, process datasheets
  • Mechanical Engineering – Static and rotating equipment specs, GA drawings, BOMs
  • Piping Engineering – Piping layouts, isometric drawings, support details, stress analysis
  • Electrical Engineering – SLDs, cable schedules, load lists, grounding layouts
  • Instrumentation Engineering – Instrument index, hook-up drawings, loop diagrams
  • Civil/Structural Engineering – Foundation layouts, structural steel drawings, trenching details

Common Detailed Engineering Deliverables:

  • Equipment and instrument datasheets
  • 3D models and general arrangement (GA) drawings
  • Isometric and fabrication drawings
  • Material Take-Off (MTO) sheets
  • Engineering schedules and progress reports

Detailed engineering ensures design integrity, constructability, and compliance with technical standards. This phase also supports procurement and vendor management.

Engineering Discipline Interface Management

Interface management is critical to the success of multidisciplinary engineering projects. It ensures effective communication, data flow, and coordination between engineering disciplines and stakeholders.

Common Engineering Interfaces:

  • Process ↔ Mechanical (e.g., flowrate vs. pump specs)
  • Piping ↔ Civil (e.g., pipe rack loads on foundations)
  • Instrumentation ↔ Electrical (e.g., instrument power supply routing)
  • Mechanical ↔ Structural (e.g., equipment nozzle orientation vs. platform supports)

Best Practices for Interface Management:

  • Maintain an up-to-date Interface Register
  • Use Interface Control Documents (ICDs)
  • Conduct regular interdisciplinary coordination meetings
  • Assign clear interface ownership and responsibilities

Effective interface management helps prevent costly rework, delays, and design conflicts during execution.

Project Engineering Tools & Templates

Project engineers use a variety of tools and templates to monitor progress, track documents, and ensure timely communication across teams.

Useful Tools:

  • Engineering document trackers (Excel or EDMS-based)
  • Interface registers and follow-up logs
  • Document transmittal and approval logs
  • Material Take-Off (MTO) and BOQ templates
  • Technical Bid Evaluation (TBE) templates
  • Design review and comment resolution sheets

Document Control and Engineering Workflow

Engineering document control is essential to ensure traceability, consistency, and regulatory compliance throughout the project lifecycle.

Key Concepts:

  • RACI Matrix – Defines roles (Responsible, Accountable, Consulted, Informed)
  • Engineering Workflow – Initial drafting → IDC → Client review → Final issue
  • Engineering Document Management System (EDMS) – Digital platforms that manage revisions, transmittals, approvals, and document status

A structured document control process prevents the use of outdated or incorrect documents during construction or procurement.

Case Studies & Lessons Learned in Project Engineering

Case 1: Vendor Delay Impact on Layouts

Delayed vendor data for a major compressor required last-minute updates to the piping layout. This caused rework, manpower rescheduling, and procurement changes, impacting the overall construction schedule.

Case 2: Interface Mismanagement in Cable Trenches

Lack of coordination between civil and electrical teams led to misaligned cable trenches. As-built corrections delayed the electrical installation by two weeks.

Lesson: Proactive interface management and vendor engagement are crucial for avoiding project delays.

Related Engineering Resources

Explore related content to deepen your understanding: