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AFA Documentation

AFA Documentation

Main

Main

About AFA

Predico Differentiators
AFA Applications
SPAD: autoDecline & Ratio Methods
GAZ & MASLO: autoRTA, Diagnostics, and Forecasting
TAHK: Multiphase Tank Models
RULON: Automation & Group Runs
TSAR: Machine Learning (M/L) Capability
Predico Company Profile & History
Predico Publications & Workshops

Data Requirements for AFA

Pressure Sources & Types of Pressures

User Manual

Getting Started

AFA Home page

The Main Menu

File Menu
Modules Menu
Project
Help

Wells (Master Well List)

Searching the Well & Project List

Projects (Project List)

Profile Menu

Admin Dashboard

Module Overview (Types of Modules)
Navigating & Selecting Modules

Create a Project

Create a Group in a Project

Set Forecast End Date
Set Forecast Start Date

Delete a Project
Copy a Project
Rename a Project
Saving a Project
Transfer a Project

Import Wells

Import Projects

Working with the Well Lists

Adding Wells to a Group/Project
Removing a Well from a Project

Types of Pressures
User Preferences

SPAD Modules

SPAD: Gas Decline
SPAD: Oil Decline
SPAD: WOR
Exit Rate
Navigating OPS and Profile Forecasts
Unsupervised Cluster Analysis Option
Limiting "b" Values

KOLDUN: CSG Monte-Carlo

TAHK: Coal Seam Gas (PSS) Forecast

Power Law: Custom Perm - Skin Relationship
OGIP Per Measure Calculations
CSG Pump & Wellbore Options

Production Constraints

Contract Rate (Rate Constraints)
Skin and Accelerated Recovery Options
Flowing Pressure and Incremental Recovery Options

GAZ Modules

GAZ: autoFMB

FMB: Productivity Index Plot
FMB P/z Plot

GAZ: autoRTA

autoRTA: Langmuir Isotherm
autoRTA: Wellbore Model
autoRTA Pre-Forecast Setting
Forecast Table and Smart Fill
RTA Sensitivities

GAZ: P/z

MASLO Modules

MASLO autoRTA
MASLO autoFMB

RULON: Roll-up, Group Runs, and Job-Queue

RULON: Group Run
RULON: Roll-Up
Job Queue
Forecasting Result Standards

Zooming & Resetting Plots
Downloading Plots
Downloading Tabulated Data

Interactive Well Map

Map Overlays
References and Attributions
GeoJSON Specification (2.9.0)
Shapefile Specification (2.9.0)

Virtual Wells

Demo Dataset

Predico Data Model
Database Integration Capabilities
Predico Model Inputs

Exiting AFA (Logging Out)

Theory & Reference Manual

Basic Petrophysical Parameters

Lithology

Porosity

Porosity: Beard & Weyl Data
Fluid Filled Porosity

Permeability

Permeability Anisotropy

Permeability Measurements

DST Measurements
Wireline Formation Tester (WFT)
Wireline (Traditional Flow & Buildup)
Cores

Isothermal Compressibility

Sorption Compressibility
Mechanics of Basic Compaction: Solids
Rock (Formation) Compressibility

Fluid Saturations

Irreducible Water

Net Pay
Homogenous Permeability and Porosity
Capillary Pressure

Core Photos

Shale Porosity: Montney
Heterogeneity & Net Pay
Vuggy Porosity 1
Vuggy Porosity 2
Shale Color
HorseShoe Canyon "Dry" Coals
Bioturbation: Bandanna Formation

PVT Correlations and Calculations

Basic Fluids

Gas PVT Correlations

Gas Specific Gravity

Apparent Molecular Mass

Acid Gases
Normalizing A Gas Mixture

Gas Deviation Factor

Video: Z-Sensitivity to Specific Gravity & Temperature

Gas Viscosity
Formation Volume Factor (Bg)
Pseudo-Critical Properties
Gas Recombination Technique
Gas Density
Standard Conditions vs In-Situ Conditions

Oil PVT Correlations

Oil API

Water Correlations

Clays and Impact on Production

Field Example 1: Clay in Sandstones
Field Example 2: Clays in Sandstones

Hydrates & Flow Assurance

Hydrate Formation
Hydrate Removal & Inhibitors

Relative Permeability

Corey Relative Permeability Curves
Permeability Jail
CSG Relative Permeability

Pseudo Pressure

Classification of Reservoirs

Types of Reservoir Fluids

Phase Envelopes & Fluid Systems

Black Oil

Undersaturated vs Saturated
Associated Gas
Non-Associated Gas

Volatile Oil
Gas Condensate
Wet Gas Reservoirs
Dry Gas Reservoirs
Biogenic vs Thermogenic Gas

Reservoir Drive Mechanism

Depletion Drive Reservoirs
Gas Cap Drive Reservoirs
Water Drive Reservoirs
Compaction Drive
Imbibition Drive

Tight Gas and Shale

Shale Porosity

Shale Permeability

Organic Matter

Transport in Shale Reservoirs

Stimulated Rock Volume (SRV)

Field Example: Micro-Seismic

Tight Gas and Shale Completions
Hybrid Shale

Tight Gas and Shale Completion Examples

Montney Gas Well Performance By Year
Montney Completions by Year

Tight Oil

Coal Seam Gas (CSG)

CSG / CBM Basics
Transport in CSG

Isotherm

Adsorption/ Desorption Mechanics
Chemical vs Physical Adsorption

Moisture & Ash Content

AR vs DAF

Temperature Effects
Measurement of Adsorption Isotherms
Undersaturation (Dewatering)
Apparent Oversaturation

CSG Isotherm Examples

North American Examples

Field Example: Canadian Mannville

Australian Examples

Bowen Basin
Surat Basin
Sydney-Gunnedah Basins
Galilee Basin

CSG Permeability / Permeability Anisotropy

CSG Permeability and Anisotropy Examples

Field Example: Corbett Creek
Field Example: Narrabri CSG Project
Field Example Bowen Basin
Field Example: Sydney Basin
Field Example: Surat Basin
Field Example: Powder River Basin Cleats

CSG Permeability vs Depth

Cleat Porosity

Cleat Compressibility

CSG Cleat Compressibility Examples

Coal Density

CSG Bulk Density Examples

Gas Composition
Molecular Structure of Coal

CSG Material Balance

Water Material Balance
Field Example: Average Reservoir Pressure Diagnostics
Cleat (Formation) Compressibility

CSG Well Spacing & Completions

Well Spacing & Dewatering

CSG Well Spacing & Completion Examples

Field Example: Corbett Creek Well Spacing
Field Example: Apache & EnCana JV
Pinnate Well Design & Similar Designs
Field Example: Mahalo Gas Hub
Field Example: Powder River Basin
Field Example: Arrow Energy- Northern Bowen Basin
Galilee Energy Pilot
Field Example: Evolution of Westside Completions

2-Phase CSG Type Curves
CSG Formation Damage
Coal Measure vs Coal Layer

Coal Molecule

Comparison of Select CSG Projects

Gas Hydrate Resources

Geomechanics

Stress Dependence Models

Matrix Shrinkage Models

Poisson's Ratio
Bulk Modulus

CSG Matrix Shrinkage and SDP Examples

San Juan Basin
HorseShoe Canyon: Trident Exploration Corp.

Material Balance Methods

Gas Material Balance

P/z Abnormally Pressured Gas Reservoirs

Field Example: Anderson "L" Pool

Generalized Form of Gas Material Balance

Oil Material Balance

Initially Undersaturated
Initially Saturated (Gas Cap Present)
Inclusion of Formation & Water Expansion

Analysis Methods

General Reservoir & Production Engineering Workflows

Rate-Pressure Correlation
Reality Check: History Matching
Importance of Data Type

Unconventional Reservoir Workflows (SPEE)

Workflow For Evaluation of Developed Reserves in Unconventional Reservoirs
Analogs for Tight Gas Sands (& other Resources)

Scaling in Reservoir Engineering

Decline Analysis

Arp's Decline

Loss Ratio

Operational vs Profile Forecasts

Decline for Unconventional Reservoirs

Hyperbolic (Arps) and Flow Regime Identification
Probability Density Function

Pressure Normalized Decline Analysis

Multiphase Pressure Normalized Decline Curve Analysis

Rate Integral Function

FMB and Rate Transient Analysis (RTA)

Transient Models & Flow Regimes

Radial Flow Models

Hydraulically Fractured Vertical Wells

Uniform Flux & Infinite Conductivity Model
Finite Conductivity Fracture Model

Composite Models

Condensate (Liquid Drop Out)

Field Example: Gas Condensate

Field Examples: Composite Model Non-Unique Interpretation

Dual Porosity
Linear Flow Models

Multi-Fractured Horizontal Well

Linear Flow Examples

South Texas Example: Vertical Frac Well
Linear Channel Flow
Eagle Ford Shale Example
Barnett Shale Gas: Well 314

Radius of Investigation

Flow Regime Identification & Analysis Methods

Bourdet (Well Testing)

Bourdet Sensitivity to Skin
Bourdet Sensitivity to Permeability
Bourdet Sensitivity to Total Compressibility

Blasingame
Normalized Pressure Integral (NPI)
Beta
Chow Pressure Group (CPG)
Other Common Methods
Fetkovich & Carter Plots

Solutions for the Diffusivity Equation under Different Flow Regimes
Flowing Material Balance
Material Balance Time

Wellbore Skin and Formation Damage

Wellbore Radius & Equivalent Wellbore Radius
Skin Components
SEM Images of Clays
Damage Due to Hydraulic Fracturing
Choke Skin
Furui: Generalized Skin Equation

RTA vs PTA Permeability

RTA/PTA Field Examples

RTA: Alberta Colorado Shale Gas
RTA: Alberta Colorado Shale Gas 2
PTA: CSG Well in Australia
PTA: CSG Well in Australia 2
MDT: CSG Well in Australia 3
PTA of CSG Well Indonesia

PTA Challenges & Errors

PTA: Gauge Drift
PTA: Insufficient Shut-in Time
PTA: Super Charging? or Pressure Interference?

PSS Models

Vertical Models

Horizontal Well Models

Extension to a Generalized Well Model

Productivity Index (PI)

Cross Flow Calculations

Water Rate Constraint Crossflow Calculations
Gas Rate Constraint Crossflow Calculations

Aquifer Model

Type Wells

Modern Type Well Construction Methods
Concerns for Type Wells: Infill Drilling, Completion & More

Multiphase Wellbore Flow

Statistical Concepts

Weighted Percentiles Approach for P10, P50, P90, and Pmean
The Lorenz Coefficient (Lk)
Population Size
Maximum Iteration Number
Parameter Consistency in Monte-Carlo
Outlier Detection Techniques
Fitting and Repeated Median Regression

Error Messages

Glossary

AFA Data Dictionary
AFA
Boundary Condition
Bubble Point
CBM
CPG
CSG_
Drainage Radius
FMB
Formation Temperature
Initial Reservoir Pressure
NPI_
OGIP
OOIP
PVT
RTA_
Solution Gas Ratio
PTA_
RNP
PNR
Tubing Roughness

Releases Notes

2.8.2 - November 25th 2025
2.8.1 - October 2nd 2025
2.8.0 - September 11th 2025
2.7.0 - June 19th 2025
2.6.0 - April 8th 2025

2.5.0 - February 13th 2025

2.5.1 - March 4th 2025

2.4.0 - October 11th 2024

2.4.1 - November 21st 2024
2.4.2 - December 17th 2024

2.3.0 - June 28th 2024

2.3.1 - July 12th 2024
2.3.2 - August 7th 2024
2.3.3 - August 28th 2024

2.2.0 - May 17th 2024

2.1.0 - April 12th 2024

2.2.1 - May 31st 2024

2.0.0 - February 9th 2024

2.0.1 - March 1st 2024
2.0.2 - March 15th 2024

Version 1

Breadcrumbs

Theory & Reference Manual
Analysis Methods
FMB and Rate Transient Analysis (RTA)

On this Page

PTA Challenges & Errors

Introduction

The following discusses practical issues related to PTA interpretation

PTA: Gauge Drift
PTA: Insufficient Shut-in Time
PTA: Super Charging? or Pressure Interference?

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