Reservoir fluids

2. PEE 232: Reservoir Fluids Properties
Spring Semester, 2011
Instructor : Dr. Salem S. Al-Marri
Office: Building No. 6 Office No. 149
Petroleum Engineering Technology
College of Technological Studies (CTS)
Public Authority for Applied Education and Training (PAAET)
Email: smalmarri@hotmail.com
Lecture: Section# 1: Tuesday 1-3 PM
Course Contents
• Components of Petroleum Fluids.
• Thermodynamic Phase Behavior.
• Behavior of Gases.
• The Five Reservoir Fluids.
• Properties of Dry Gases.
• Properties of Wet Gases.
• Properties of Black Oils.
Course Grade System
The course grade system will be divided as follows:
A. Lecture Grade 80%
B. Lab Grade 20%
The lecture grades will be divided as follows:
Attendance 10%
H.W. & Quizzes 25%
Mid-Terms 30%
Final Exam 35%
Total 100%
2

3. 3
Petroleum Fluids Properties
Lecture # 8: Five Reservoir
Fluids (Chapter 5)

4. 4
Petroleum Fluids Properties
Used to visualize the fluids
production path from the reservoir
to the surface
To classify reservoir fluids
Visualize miscible processes
Pressure vs. Temperature Diagrams

5. 5
Pressure-Temperature Diagram
for Multicomponent Systems
Reservoir
Pressure
Reservoir Temperature
60%
20%
0%
2-Phase
1-Phase 1-Phase
CP

6. 6
Why do we need to classify
Reservoir Fluids?
Determine fluid sampling
Determine types and sizes of surface
equipment
Dictate depletion strategy
Determine selection of EOR method
Determine techniques to predict oil &
gas reserves
Determine Material Balance calculations

7. 7
Phase Envelopes
Critical
Point
Cricondenbar
Cricondentherm
BubblepointCurve
Dew Point Curve
Quality
Lines
Temperature
Pressure
75%
50%
25%
Fixed
Composition

8. 8
Classification of Reservoirs
based on Phase Diagram
Gas Reservoirs (Single Phase)
Gas Condensate Reservoirs (Dew-
Point Reservoirs):

Undersaturated Solution-Gas
Reservoirs (Bubble-Point
Reservoirs):


9. 9
Phase Diagram of a
Dry Gas Reservoir
Temperature
Pressure
Path of Production
Initial Reservoir
Conditions
Separator Conditions
CP

10. 10
Phase Diagram of a
Wet Gas Reservoir
Temperature
Pressure
Path of Production
Initial Reservoir
Conditions
Separator Conditions
CP

11. 11
Phase Diagram of a
Retrograde Gas Reservoir
Temperature
Pressure
Initial Reservoir
Conditions
CP
Path of Production
Separator Conditions
Temperature
Pressure
Initial Reservoir
Conditions
CP
Path of Production
Separator Conditions
Temperature
Pressure
Initial Reservoir
Conditions
CP
Path of Production
Separator Conditions

12. 12
Phase Diagram of a
Volatile Oil Reservoir
Temperature
Pressure
Initial Reservoir
Conditions
CP
Path of Production
Separator Conditions
75%
50%
25%

13. 13
Phase Diagram of a
Black Oil Reservoir
Temperature
Pressure
Initial Reservoir
Conditions
CP
Path of Production
Separator Conditions
25%
50%
75%

14. 14
Phase envelopes of different
mixtures with different proportions
of same HC components
0
1000
2000
3000
4000
5000
6000
7000
Pressure
(psia)
-200 -100 0 100 200 300 400 500 600 700 800
Temperature
o
F
Critical Points
Dry Gas
Wet Gas
Condensate
Volatile I
Black Oil
TR
Volatile I
Volatile II

15. 15
Typical Reservoir Fluid Compositions
Component Black Oil Volatile Oil Gas Condensate Wet Gas Dry Gas
C1
48.83 64.36 87.07 95.85 86.67
C2
2.75 7.52 4.39 2.67 7.77
C3
1.93 4.74 2.29 0.34 2.95
C4
1.60 4.12 1.74 0.52 1.73
C5
1.15 3.97 0.83 0.08 0.88
C6
1.59 3.38 0.60 0.12
C7
+ 42.15 11.91 3.80 0.42
Mw
C7
+ 225 181 112 157
GOR 625 2000 18,200 105,000 -
Tank oAPI 34.3 50.1 60.8 54.7 -
Liquid
Color
Greenish
Black
Medium
Orange
Light
Straw
Water
White
-

16. 16
Compositional
Distribution
of
Reservoir
Fluids

17. 17
Classification of Reservoirs
based on Production and PVT
data
GAS CONDENSATE RESERVOIRS:
GOR between 70,000-100,000
SCF/STB
Density greater than 60 ºAPI
Light in color
C7
+ composition < 12.5%

18. 18
Classification of Reservoirs
based on Production and PVT
data
VOLATILE OIL RESERVOIRS:
GOR between1,000-8,000 SCF/STB
Density between 45-60 ºAPI
Oil FVF greater than 2.00 (high
shrinkage oils)
Light brown to green in color
C7
+ composition > 12.5%

19. 19
BLACK OIL RESERVOIRS:
GOR less than 1,000 SCF/STB
Density less than 45 ºAPI
Reservoir temperatures less than 250
ºF
Oil FVF less than 2.00 (low shrinkage
oils)
Dark green to black in color
C7
+ composition > 30%
Classification of Reservoirs
based on Production and PVT
data

20. 20
Assignment
Read and make a summary of
revised & newer criteria for
classification of Reservoir Fluids
from given paper by William D.
McCain in JPT September 1994

21. 21
JPT paper Study Guide
What are the distinctive features
of black oils in terms of
Initial GOR & GOR vs time
Initial API & API vs time
Compositions
Color

22. 22
JPT paper Study Guide
What are the distinctive features
of volatile oils in terms of
Initial GOR & GOR vs time
Initial API & API vs time
Compositions
Color

23. 23
JPT paper Study Guide
What are the distinctive features
of Condensate gases in terms of
Initial GOR & GOR vs time
Initial API & API vs time
Compositions
Color

24. 24
JPT paper Study Guide
What are the distinctive features
of Dry gases in terms of
Initial GOR & GOR vs time
Compositions

25. Classifications or grades
• Generally speaking, oil with an API gravity between 40 and 45 commands the
highest prices. Above 45 degrees the molecular chains become shorter and less
valuable to refineries.
• Crude oil is classified as light, medium or heavy, according to its measured API
gravity.Light crude oil is defined as having an API gravity higher than 31.1 °API
• Medium oil is defined as having an API gravity between 22.3 °API and 31.1 °API
• Heavy oil is defined as having an API gravity below 22.3 °API.
• Crude oil with API gravity less than 10 °API is referred to as extra heavy oil or
bitumen .Bitumen derived from the oil sands deposits in the Alberta, Canada area has
an API gravity of around 8 °API.
25