Field Production Profiles Overview

Introduction

Field Production Profiles (FPP) extend individual well decline analysis to field-level forecasting. While DCA models forecast single-well production, FPP combines multiple wells with different start dates, peak rates, and decline characteristics into an aggregate field forecast.

FPP is essential for:

• Development planning — sizing surface facilities and pipelines
• Economic evaluation — NPV and IRR calculations for field investments
• Reserves booking — proved, probable, possible (1P/2P/3P) estimates
• Portfolio management — comparing development options

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Profile Phases

A typical field production profile has three distinct phases:

    ▲ Rate
    │
    │              ┌──────────────────┐
    │             ╱│                  │╲
    │           ╱  │     PLATEAU      │  ╲
    │         ╱    │                  │    ╲
    │       ╱      │                  │      ╲
    │     ╱        │                  │        ╲
    │   ╱  BUILDUP │                  │ DECLINE  ╲
    │ ╱            │                  │            ╲
    │╱             │                  │              ╲
    └──────────────┴──────────────────┴────────────────▶ Time
         t_bu              t_pl              t_dec

Phase Descriptions

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Single Field Profile

Buildup Phase

Rate ramps up linearly or stepped as new wells are drilled:

$$q(t) = q_{plateau} \times \frac{t}{t_{bu}} \quad \text{for } t < t_{bu}$$

Or for stepped drilling (more realistic):

$$q(t) = n(t) \times q_{well}$$

Where $n(t)$ is the number of producing wells at time $t$.

Plateau Phase

Rate is held constant at the maximum (facility-constrained) level:

$$q(t) = q_{plateau} \quad \text{for } t_{bu} \le t < t_{bu} + t_{pl}$$

Plateau ends when:

• Total deliverability from all wells drops below plateau rate
• Contractual obligation expires
• Water cut or GOR reaches economic limit

Decline Phase

After plateau, the field follows an aggregate decline:

$$q(t) = q_{plateau} \times f(t - t_{decline\_start})$$

Where $f$ is typically an Arps decline function (exponential, hyperbolic, or harmonic).

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Multi-Well Aggregation

Schedule-Based Forecasting

For fields with staggered well starts:

$$Q_{field}(t) = \sum_{i=1}^{N_{wells}} q_i(t - t_{start,i})$$

Where:

• $q_i$ = production profile of well $i$
• $t_{start,i}$ = start date of well $i$
• Each well has its own peak rate and decline parameters

Cumulative Production

$$N_p(t) = \int_0^t Q_{field}(\tau) d\tau$$

For discrete time steps:

$$N_p(t_n) = \sum_{k=0}^{n-1} Q_{field}(t_k) \Delta t_k$$

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Available Calculations

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Relationship to DCA

FPP builds on DCA but adds:

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Best Practices

1. Start with individual well type curves — base field profile on representative well performance
2. Account for facility constraints — pipeline, separator, and compressor capacities limit plateau rate
3. Use realistic drilling schedules — rig availability and well spacing affect buildup
4. Include production efficiency — downtime, workovers reduce actual production below theoretical
5. Sensitivity analysis — vary well count, decline rate, plateau length for range of outcomes

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Related Documentation

FPP Details

• Drilling Schedule — Multi-well scheduling and aggregation

Supporting Topics

• DCA Overview — Individual well decline models
• DCA Arps — Classical decline equations used in decline phase
• IPR Overview — Well deliverability for plateau determination

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References

1. Arps, J.J. (1945). "Analysis of Decline Curves." Transactions of AIME, 160, 228-247.

2. Towler, B.F. (2002). Fundamental Principles of Reservoir Engineering. SPE Textbook Series Vol. 8.

3. Dake, L.P. (2001). The Practice of Reservoir Engineering, Revised Edition. Elsevier.

4. Economides, M.J. and Nolte, K.G. (2000). Reservoir Stimulation, 3rd Edition. Wiley.

5. Craft, B.C. and Hawkins, M.F. (1991). Applied Petroleum Reservoir Engineering, 2nd Edition. Prentice Hall.