Post on 13-Jan-2016
PETE 310PETE 310
Lecture # 5Lecture # 5
Phase Behavior – Pure Phase Behavior – Pure SubstancesSubstances
Learning ObjectivesLearning Objectives
After completing this chapter After completing this chapter you will be able to:you will be able to:
Understand pure component Understand pure component phase behavior as a function of phase behavior as a function of pressure, temperature, and pressure, temperature, and molecular size.molecular size.
Understand the behavior of Understand the behavior of binary and multicomponent binary and multicomponent mixtures mixtures (lectures 6 & 7)(lectures 6 & 7)
The Need to Understand The Need to Understand Phase BehaviorPhase Behavior
As oil and gas are produced from the As oil and gas are produced from the reservoir, they are subjected to a reservoir, they are subjected to a series of pressure, temperature, and series of pressure, temperature, and compositional changes. compositional changes.
Such changes affect the volumetric Such changes affect the volumetric and transport behavior of these and transport behavior of these reservoir fluids and, consequently, reservoir fluids and, consequently, the produced oil and gas volumes.the produced oil and gas volumes.
The Need to Understand The Need to Understand Phase BehaviorPhase Behavior
Except polymer flooding, all of EOR Except polymer flooding, all of EOR methods rely on the phase methods rely on the phase behavior of reservoir fluids and behavior of reservoir fluids and fluids injected into the reservoir. fluids injected into the reservoir.
This behavior is used to classify This behavior is used to classify the recovery method (i.e., thermal, the recovery method (i.e., thermal, miscible, chemical, etc.), and to miscible, chemical, etc.), and to design the recovery process. design the recovery process.
Major DefinitionsMajor Definitions
System:System: A body of matter with A body of matter with finite boundaries (physical or finite boundaries (physical or virtual) virtual)
Closed System:Closed System: Does not exchange Does not exchange matter with surroundings but may matter with surroundings but may exchange energy (heat).exchange energy (heat).
Open System:Open System: Does exchange Does exchange matter and energy with matter and energy with surroundings.surroundings.
Major DefinitionsMajor Definitions
Phase:Phase: A portion of the A portion of the system which has system which has homogeneous intensive homogeneous intensive properties and it is bounded properties and it is bounded by a physical surface. by a physical surface.
Interface:Interface: Separates two or Separates two or more phases. These phases more phases. These phases are solid, liquid(s), and gas. are solid, liquid(s), and gas.
Major DefinitionsMajor Definitions
Intensive Properties:Intensive Properties: Independent of system Independent of system mass (i.e density)mass (i.e density)
Extensive Properties:Extensive Properties: Dependent of system mass Dependent of system mass (i.e volume)(i.e volume)
Major DefinitionsMajor Definitions
Homogeneous System:Homogeneous System: Intensive Intensive properties change continuously and properties change continuously and uniformly (smoothly)uniformly (smoothly)
Heterogeneous System:Heterogeneous System: System made up System made up of two or more phases in which the of two or more phases in which the intensive properties change abruptly at intensive properties change abruptly at phase-contact surfacesphase-contact surfaces
Major DefinitionsMajor Definitions
Properties:Properties: Characteristics of a Characteristics of a system (phase) that may be system (phase) that may be evaluated quantitatively. These are,evaluated quantitatively. These are, Phase density (liquid, gas, solid)Phase density (liquid, gas, solid) CompressibilityCompressibility Surface tensionSurface tension Viscosity Viscosity Heat capacityHeat capacity Thermal conductivity Thermal conductivity
Phase DiagramsPhase Diagrams
Types of phase diagrams for a Types of phase diagrams for a single component (pure single component (pure substance)substance)
(PT)(PT) (PV) or (P(PV) or (P)) (TV) or (T(TV) or (T
Phase DiagramsPhase Diagrams
Single Component Phase DiagramSingle Component Phase DiagramP
ress
ure
P c
TemperatureT c
Liquid (1 phase)
Vapor (1 phase)
Solid
(1 phase)
Sublimation Curve (2 phases)
Triple Point
(3 phases)
Vapor Pressure
Curve (2 phases)
Critical
Point
Fusion Curve2 phases
Phase DiagramsPhase DiagramsVapor Pressure CurveVapor Pressure Curve
Pre
ssu
re
Temperature
Vapor
Liquid
Critical Point
l
v
Pc
T c
Hydrocarbon Families Hydrocarbon Families Physical Properties Physical Properties
One point in theOne point in theVapor Pressure CurveVapor Pressure Curve
Pressure vs Specific Pressure vs Specific Volume Pure SubstanceVolume Pure Substance
Tc
2-phase
T
Specific Volume (ft3 / lbm)
Pre
ssu
re (
psi
a)
Vv
VL
CP
Tabulated critical properties Tabulated critical properties (McCain)(McCain)
Pure Component Pure Component PropertiesProperties
Heat Effects Accompanying Heat Effects Accompanying Phase Changes of Pure Phase Changes of Pure
SubstancesSubstances
Lv = TV dPv
dTWith
V = VMg-VMl
Btu/lb-mol
Clapeyron equation
Heat Effects Heat Effects Accompanying Phase Accompanying Phase
Changes of Pure Changes of Pure SubstancesSubstances
Lv = TV dPv
dT
=
Approximate relation (Clausius - Clapeyron Equation)
dPv
dT
RT2 Pv
Lv
Example of Heat Effects Example of Heat Effects Accompanying Phase Accompanying Phase
Changes Changes Steam flooding Problem:Steam flooding Problem:
Calculate how many BTU/day Calculate how many BTU/day (just from the latent heat of (just from the latent heat of steam) are provided to a steam) are provided to a reservoir by injecting 6000 reservoir by injecting 6000 bbl/day of steam at 80% quality bbl/day of steam at 80% quality and at a T=462 and at a T=462 ooF F
COX - Vapor Pressure COX - Vapor Pressure ChartsCharts
(normal paraffins)(normal paraffins)
Pre
ssu
reP
ress
ure
Temperature Temperature
heavier heavier
Non-linear scaleNon-linear scale
Log scaleLog scale
Determination of Fluid Determination of Fluid PropertiesProperties
Temperature of Test Constant
Vt1
Vt2
Vt3
=V
b
Vt5
Vt4
liquid liquid liquidliquid
liquid
gas gas
Hg Hg HgHg
Hg
P1 >> P
sP
2 > P
sP
3 = P
sP
4 = P
sP
5 =P
s
1 2 3 4 5Ps =saturation pressurePs =saturation pressure
Vapor Pressure Vapor Pressure DeterminationDetermination
Pre
ssur
e
PS
Volume
VL
TT22
TT11
HomeworkHomework
See Syllabus for HW Problems See Syllabus for HW Problems due due