Key Decisions in Oil & Gas Field Development Planning: A Practical Engineering Guide


Field development planning is a multidisciplinary process that defines how an oil or gas field will be produced safely, economically, and efficiently over its entire life cycle.

This lesson introduces the critical decisions that must be addressed before committing to a development concept.


1. Reservoir Depletion Strategy

The first and most fundamental question in field development is:

How will the reservoir energy be managed to produce hydrocarbons?

Common depletion strategies include:

  • Natural Depletion
    Production relies solely on the reservoir’s natural pressure.

    • Lower capital cost

    • Production declines as pressure drops

  • Water Injection
    Water is injected to maintain reservoir pressure and improve recovery.

    • Increases ultimate recovery

    • Requires injection wells and facilities

  • Gas Injection
    Gas is injected to support pressure or improve sweep efficiency.

    • Common in gas or condensate reservoirs

    • Higher operational and compression requirements

📌 This decision impacts:

  • Recovery factor

  • Number of wells

  • Field life

  • Overall project economics


2. Artificial Lift Strategy

As reservoir pressure declines, natural flow may no longer be sufficient.

Artificial lift options include:

  • Gas lift

  • Electrical Submersible Pumps (ESP)

  • Subsea boosting systems

Key questions:

  • Will artificial lift be required from day one or later in field life?

  • Should the system be designed upfront for future lift installation?

📌 Early planning avoids costly retrofits later.


3. Production Profile Definition

The production profile defines how much and how long the field will produce.

Key parameters:

  • Plateau production rate

  • Plateau duration

  • Decline rate

📌 The production profile directly drives:

  • Facility sizing

  • Pipeline diameter

  • Export capacity

  • Financial metrics (NPV, IRR)


4. Phased Development Strategy

Instead of developing the entire field at once, production can be executed in phases.

Advantages of phased development:

  • Lower upfront capital expenditure

  • Early production and cash flow

  • Ability to learn and optimize future phases

📌 Commonly used in:

  • Deepwater developments

  • High-uncertainty reservoirs


5. Wells and Completion Strategy

Well design is one of the largest cost and risk contributors.

Key decisions:

  • Number of wells

  • Completion type (open hole, cased and perforated, intelligent completions)

  • Sand control requirements

Well trajectories:

  • Vertical

  • Deviated

  • Horizontal

📌 These choices affect productivity, water/gas breakthrough, and long-term recovery.


6. Surface or Subsea Development Concept

A fundamental architectural decision:

Options:

  • Surface wells

  • Subsea wells

  • Hybrid surface–subsea systems

The selection depends on:

  • Water depth

  • Distance to shore or host facility

  • Environmental conditions

  • Existing infrastructure


7. Pre-Drilling and Rig Selection

Pre-drilling:

Drilling wells before facility installation can:

  • Reduce overall project schedule

  • Enable earlier first production

Rig selection depends on:

  • Water depth

  • Environmental conditions

  • Well complexity

Common rig types:

  • Jack-up rigs

  • Semi-submersibles

  • Drillships


8. Safety and Field Layout Considerations

Safety is an integral part of field development planning.

Key considerations:

  • Separation or grouping of hazardous functions

  • Safe distances between wells, processing, and accommodation

  • Emergency access and escape routes

📌 A well-designed layout reduces risk to personnel and assets.


9. Export Strategy

Produced hydrocarbons must be transported to market.

Two main export options:

  • Standalone export system

  • Tie-in to existing infrastructure

Key trade-offs:

  • Capital cost vs. availability

  • Schedule impact

  • Operational dependency on third-party systems


10. Construction and Execution Strategy

Successful development requires realistic execution planning.

Key aspects:

  • Availability of fabrication yards

  • Local content requirements

  • Offshore installation windows

  • Project execution schedule


11. Contractual Strategy

The contracting approach strongly influences cost and risk allocation.

Common strategies:

  • EPC (Engineering, Procurement, Construction)

  • EPCI (including Installation)

  • Multiple package contracting

📌 Contract strategy must align with:

  • Project complexity

  • Risk tolerance

  • Market conditions


Key Takeaway

Field development planning is not a single technical decision, but a system-level optimization balancing:

  • Reservoir performance

  • Technical feasibility

  • Safety

  • Cost

  • Schedule

  • Long-term value

Every early decision has long-lasting consequences throughout the life of the field.



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