production-forecaster

Production Forecaster

Forecast oil and gas production using industry-standard decline curve analysis methods. Supports Arps decline models, type curve generation, and EUR (Estimated Ultimate Recovery) calculations for reserve estimation.

When to Use

• Forecasting future production for oil and gas wells
• Estimating EUR (Estimated Ultimate Recovery)
• Generating type curves for field development planning
• Fitting decline parameters to historical production data
• Comparing well performance across different fields
• Supporting reserve booking and economic evaluation
• Analyzing production trends and anomalies

Core Pattern

Historical Production → Decline Curve Fit → Parameter Estimation → Forecast → EUR

Decline Curve Models

Arps Decline Equations

Exponential Decline (b = 0):

q(t) = qi * exp(-Di * t)

Hyperbolic Decline (0 < b < 1):

q(t) = qi / (1 + b * Di * t)^(1/b)

Harmonic Decline (b = 1):

q(t) = qi / (1 + Di * t)

Where:

• q(t) = Production rate at time t
• qi = Initial production rate
• Di = Initial decline rate
• b = Decline exponent (b-factor)
• t = Time

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Modified Hyperbolic Decline

For long-term forecasts, use terminal decline rate to prevent over-optimistic recoveries:

q(t) = qi / (1 + b * Di * t)^(1/b)     when D(t) > D_min
q(t) = q_switch * exp(-D_min * t')     when D(t) <= D_min

Where D_min is the terminal decline rate (typically 5-8%/year) and t' is time from switch point.

Duong Decline Model (Unconventional)

For unconventional wells with transient linear flow:

q(t) = q1 * t^(-m) * exp(-a/(1-m) * (t^(1-m) - 1))

Where:

• q1 = Rate at t=1 day
• a = Intercept (controls EUR)
• m = Slope (controls decline steepness)

Stretched Exponential Decline

Alternative for unconventional with varying flow regimes:

q(t) = qi * exp(-(t/τ)^n)

Where:

• τ = Characteristic time constant
• n = Stretch parameter (0 < n < 1)

Type Curve Analysis Framework

Normalization Methods

Type Curve Bins

Group wells for representative type curves:

Type Curve Confidence Intervals

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Implementation

Data Models

from dataclasses import dataclass, field
from datetime import date
from typing import Optional, List, Dict, Tuple
from enum import Enum
import numpy as np
import pandas as pd

class DeclineType(Enum):
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    """Decline curve types."""
    EXPONENTIAL = "exponential"       # b = 0
    HYPERBOLIC = "hyperbolic"         # 0 < b < 1
    HARMONIC = "harmonic"             # b = 1
    MODIFIED_HYPERBOLIC = "modified"  # Hyperbolic with terminal decline
    DUONG = "duong"                   # Unconventional transient
    STRETCHED_EXP = "stretched"       # Stretched exponential

class NormalizationMethod(Enum):
    """Type curve normalization methods."""
    PEAK = "peak"
    FIRST_MONTH = "first_month"
    IP_30 = "30_day_ip"
    IP_90 = "90_day_ip"
    MOVING_AVG = "moving_average"
    CUMULATIVE = "cumulative_at_time"

class TypeCurveBinType(Enum):
    """Type curve binning categories."""
    FORMATION = "formation"
    COMPLETION = "completion"
    WATER_DEPTH = "water_depth"
    LATERAL_LENGTH = "lateral_length"
    PROPPANT = "proppant"
    VINTAGE = "vintage"
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    """Arps decline curve types."""
    EXPONENTIAL = "exponential"  # b = 0
    HYPERBOLIC = "hyperbolic"    # 0 < b < 1
    HARMONIC = "harmonic"