Ideal Example Stress Tests
The following presents three simple, ideal stress tests- These include a Step-Rate Injection Test,
a Flow-Back rFest, and Injection/Decline Test. Each test is “real”, and consists of data exactly as
measured in the ﬁeld
ENERGY AND CLIMATE | MAY 2012
Energy and Climate | May 2012
2012 Carnegie Endowment for International Peace. All rights reserved.
The Carnegie Endowment does
This section reviews the basic physics of hydraulic fracture propagation, growth, and final fracture
geometry. In addition to leading toward a general understanding of fracture growth, reviewing the basic
Homework: Integrated Fracture Analysis
The Tiger No. 2 well was drilled as a development well to a known, productive, oil sand. The initial well in this
formation was completed with a conventional, inside casing, circulating gravel
Fracture Design Variables
H , E , C , KIc-App
, Q, V
Building A Basis of Design
H, E, C, KIC , Q, TP
3 C H P TP + w H
H ( P Closure )
In-Situ Rock Stresses
Unconventional Gas Reservoirs
Magnitude of Stress
Origin/Magnitude of Stresses
(Equal to Overburden, V ?)
Local Stresses & Tensile Strength
For a vertical well is
usually the minimum total
For a vertical well is
usually the maximum
total horizontal stress
PETE 4090- Unconventional Hydrocarbon Reservoirs
Dr. Arash Dahi
Department of Petroleum Engineering
Office: Patrick Taylor Hall 2115
Office hours: T-Th 2:30 3:30.
PETE 4090 Unconventional Reservoirs
Fracture Geometry Homework
Plot and compare the average fracture widths vs. xf obtained from the PKN and KGD
models, Q = 80bpm, viscosity = 5cp, Poissons ratio = 0.22, Youngs modulus = 4*106
psi, and hf = 120
How long is a propped fracture?
How conductive is a propped fracture?
What is the equivalent wellbore radius?
What is folds of increase?
How does the distance to the nearest flow boundary
Primary Instructor: A. Dahi
Office: Room 139, Old Forestry Bldg.
Office Hours: M-W 2:30-3:30
Class: M-W 4:30- 5:50 PM
The goal of t
Major Fracture Design Variables
source: Economides at al.: Petroleum Well Construction
Which wellbore-fracture orientation is favorable?
What can be done?
How large should the treatment be?
Fracture Design Working Process
Calculate In Situ Proppant Kfw
Fracture length and FOI
Folds of increase = FOI SS
ln(re / rw' )
ln(re / rw )
Large fracture aspect ration indic