From Exploration to Production: A Step-by-Step Guide to Oil and Gas Operations

Stage 0: Access, Licences & Stakeholders

Before technical work begins, operators secure exploration rights, align with regulators and communities, and establish the project governance framework.
Success looks like: Clear licence terms, stakeholder map, environmental baseline, and a risk register.

Stage 1: Exploration (Geology, Geophysics & Seismic)

Geoscientists screen basins, acquire 2D/3D seismic, and interpret subsurface structures to define prospects.
Key activities: Basin modelling, seismic acquisition/processing, prospect ranking, well proposals.
Deliverables: Prospect inventory, chance-of-success estimates, initial HSE plan for fieldwork.

Stage 2: Exploration Drilling

One or more exploration wells test the presence of hydrocarbons.
Key activities: Well design, permitting, rig mobilisation, drilling, wireline logging, well testing.
Success metrics: Hydrocarbon shows, reservoir quality, pressure/temperature data, safe operations.
HSE focus: Blowout prevention, well control, SIMOPS management.

Stage 3: Appraisal

If a discovery is made, appraisal wells refine the reservoir model and production strategy.
Key activities: Additional wells/sidetracks, cores, flow tests, dynamic modelling.
Deliverables: Contingent resources, production forecasts, development concepts, economics.

Stage 4: Concept Selection (Pre-FEED)

Engineering and commercial teams compare development options (tie-back vs new facility, pipeline sizing, power, export route).
Key activities: Option screening, routings, constructability, permitting pathways, high-level cost/schedule.
Decision gate: Select the concept that best meets safety, economics, and environmental objectives.

Stage 5: FEED (Front-End Engineering Design)

The selected concept is engineered in detail enough to price and permit.
Key activities: PFDs/P&IDs, pipeline hydraulics, equipment sizing, plot plans, material selection, integrity philosophy, HAZID/HAZOP.
Deliverables: FEED package, Class 3 estimate, execution plan, regulator submissions.

Stage 6: Detailed Engineering, Procurement & Fabrication (EPC)

Disciplines produce AFC (approved-for-construction) drawings; procurement secures equipment; fabrication of skids/modules begins.
Engineering: Process, mechanical/pipeline, civil/structural, E&I/controls, metering.
Procurement: Vendor pre-qualification, technical bid evaluation, expediting, logistics.
Quality: ITPs, WPS/PQR/WPQ, material traceability, FATs.
Standards: API, ASME B31.3/B31.4, IEC/ATEX, ISA, relevant national codes.

Stage 7: Construction & Installation

Field crews execute pipeline and facility works safely and to spec.
Pipeline scope: ROW prep, trenching, welding, NDT (UT/RT/MT/PT), coating/holiday test, lowering-in, backfill, hydrotest, reinstatement.
Facility scope: Foundations, steelwork, equipment setting, piping, cabling, junction boxes, panels, earthing, insulation/painting.
Controls: Permit-to-work, lifting plans, confined space entries, daily progress tracking.
Documentation: Weld maps, test packs, red-lines, inspection records.

Stage 8: Commissioning & Start-Up

Systems are verified safe and functional before hydrocarbons flow.
Pre-com: Flushing/cleaning, pressure tests, instrument loop checks, energisation.
Commissioning: Functional tests, cause-and-effect, interlocks, metering calibration, performance runs.
Handover: Punch-list closure, O&M manuals, as-builts, MDR (Manufacturer’s Data Record).
Goal: “Build-right-first-time” start-up with zero incidents and clear ownership by Operations.

Stage 9: Operations & Maintenance (O&M)

The asset moves into routine operation focused on uptime and efficiency.
Practices: CMMS-driven PMs, critical spares, reliability programmes (RCM), TAR (turnarounds), emergency response readiness.
KPIs: Availability, MTBF, energy intensity, emissions, cost per produced unit.
Digital: Condition monitoring, work order analytics, mobile QHSE apps.

Stage 10: Asset Integrity & Regulatory Assurance

Integrity programmes protect people, environment, and production.
Activities: RBI planning, inspection (NDT, corrosion monitoring), cathodic protection, anomaly assessment (FFS), remedial works.
Records: Inspection history, repairs, over-due actions, audit trail.
Outcome: Fewer leaks, longer equipment life, compliant operation.

Stage 11: Brownfield Upgrades & Debottlenecking

Most assets undergo modifications to increase capacity or reduce risk.
Works: Tie-ins, valve replacements, metering upgrades, controls modernisation, new skids.
Controls: Hot/cold work permits, isolations/LOTO, SIMOPS planning to minimise downtime.

Stage 12: Decommissioning (End-of-Life)

When production ceases, assets are made safe and removed or repurposed.
Scope: Plug & abandon wells, purge/clean systems, dismantle equipment, site restoration and monitoring.
Drivers: Regulatory compliance, environmental outcomes, and stakeholder commitments.

Where Geigerpipe Fits In

• EPC Delivery: Pipelines/flowlines, modular skids, brownfield upgrades, and tie-backs.
• Construction & QA/QC: Certified welders, inspectors, and disciplined ITPs with full traceability.
• Commissioning & Start-Up: Procedures, loop checks, performance tests, handover dossiers.
• O&M & Turnarounds: Preventive maintenance, call-outs, TAR planning and execution.
• Asset Integrity: NDT, corrosion management, RBI, defect assessment, and targeted repairs.
• Project Controls: Primavera/MSP schedules, earned value, digital ITPs/MDRs, dashboard reporting.
• QHSE: Integrated system aligned to ISO 9001, ISO 14001, ISO 45001 principles; stop-work authority for all supervisors.

A Simple Stage-Gate View (at a glance)

Explore → Appraise → Select (Pre-FEED) → Define (FEED) → Execute (EPC & Construction) → Commission → Operate & Maintain → Upgrade → Decommission

Each gate checks safety, environment, technical readiness, cost/schedule, and stakeholder alignment before proceeding.

Typical Documents by Phase (quick reference)

• Exploration/Appraisal: Seismic reports, well results, environmental baseline.
• FEED: PFDs, P&IDs, equipment lists, HAZID/HAZOP, Class 3 estimate.
• EPC: AFC drawings, MTOs, ITPs, WPS/PQR, inspection/test records, FAT/SAT.
• Construction: Weld/NDT logs, coating records, hydrotest packs, red-lines.
• Commissioning: Checklists, loop packs, cause-and-effect, performance tests.
• Operations: CMMS records, KPI dashboards, inspection reports, TAR close-outs.
• Integrity: RBI plans, thickness surveys, CP readings, FFS assessments.
• Decommissioning: P&A programmes, cleaning certificates, waste manifests, restoration reports.

Final Word

From the first seismic line to a stable, efficient operation, success comes from disciplined engineering, safe construction, quality documentation, and proactive integrity management. That is where Geigerpipe adds value—safely, on schedule, and to international standards.

About Geigerpipe

Geigerpipe designs, builds, and maintains critical oil & gas infrastructure—pipelines, modular facilities, commissioning, and asset-integrity programmes—delivered with strict QHSE discipline and full traceability.