3_pp-412 digrama de fases - monofasico - multifasico.pdf
TRANSCRIPT
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GAS NATURAL YGAS NATURAL YGAS NATURAL YGAS NATURAL YCONDENSADOS ICONDENSADOS ICONDENSADOS ICONDENSADOS I
PPPPPPPP----412412412412
Ing. William Navarro
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A PARTIR DE:
DIAGRAMA DE FASES-PRUEBAS PVT
CARACTERIZACIN DE YACIMIENTOS EN BASE A LA MEZCLA DE HIDROCARBUROS QUE CONTIENEN
DIAGRAMA DE FASES-PRUEBAS PVT
INFORMACIN DE PRUEBAS DE PRODUCCIN
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IntroduccinIntroduccinIntroduccinIntroduccin
Gas y petrleo son mezclas de fluidos que estn sujetos a diferentes ambientes de P & T
Estas medios se denominan Phases. Phase es una porcin homognea de un sistema
heterogneo Es homogneo en su composicin Es homogneo en su composicin Posee superficies limites Son separables fsicamente
Entender el comportamiento de phase permite determinar el comportamiento de los fluidos en el reservorio y en el sistema de produccin-transporte.
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DefinicionesDefinicionesDefinicionesDefiniciones
Sistema
Amount of substance within given boundaries under specific conditions composed of a number of components.
If anything moves across the boundary system will have changed.have changed.
Componentes
Sustancias puras que producen el sistema a lascondiciones de P y T.
Ejem. C1, C2, CO2, agua
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DefinicionesDefinicionesDefinicionesDefiniciones
Phase
Porcin fsica distinta de materia, que tiene propiedades fsicas y qumicas uniformes.
Ejem. Agua liquida-Hielo.
Equilibrio Equilibrio
Un sistema esta en equilibrio cuando no ocurren cambios en el tiempo de sus propiedades fsicas
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DefinicionesDefinicionesDefinicionesDefiniciones
Propiedades intensivas
Independientes de la cantidad de materia. Ejem. Densidad, volumen especifico, factor de
compresibilidad
Propiedades extensivas Propiedades extensivas
Dependen de la cantidad de materia presente. Ejem. Volumen
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PRESIN TEMPERATURA ATRACCIN MOLECULAR REPULSIN MOLECULAR
FACTORES FSICOS QUE CONTROLAN EL FACTORES FSICOS QUE CONTROLAN EL FACTORES FSICOS QUE CONTROLAN EL FACTORES FSICOS QUE CONTROLAN EL COMPORTAMIENTO DE FASESCOMPORTAMIENTO DE FASESCOMPORTAMIENTO DE FASESCOMPORTAMIENTO DE FASES
PRESIN Y Confinan las MolculasATRACCIN MOLECULAR
TEMPERATURA Y Dispersan las MolculasREPULSIN MOLECULAR
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TemperaturaTemperaturaTemperaturaTemperatura ---- PresinPresinPresinPresin
PresinPresinPresinPresin Refleja la frecuencia de colisin de las moleculas en las
paredes del contenedor. Ms moleculas incrementa presin.
Fuerzas de atraccinFuerzas de atraccinFuerzas de atraccinFuerzas de atraccin----repulsin entre repulsin entre repulsin entre repulsin entre Fuerzas de atraccinFuerzas de atraccinFuerzas de atraccinFuerzas de atraccin----repulsin entre repulsin entre repulsin entre repulsin entre moleculas.moleculas.moleculas.moleculas.
Fuerzas de atraccin aumentan a medida que la distancia entre las moleculas disminuye hasta que las cargas se superponen.
Al disminuir ms la distancia se incrementa las fuerzas de repulsin
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TemperaturaTemperaturaTemperaturaTemperatura ---- PresinPresinPresinPresin
Temperatura
Indicativo de la energa Cinetica de las moleculas. Si se adiciona calor se incrementa energa Kinetica Las moleculas se mueven ms separados.
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Gases & LiquidosGases & LiquidosGases & LiquidosGases & Liquidos
Gases
Molecules are widely spaced. Attractive forces exist between the molecules.
Liquidos
Molecules are closer together. Molecules are closer together. Repelling force which causes liquid to resist
further compression.
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SistemaSistemaSistemaSistema PuroPuroPuroPuro
Useful to examine pure systems to gain insight into more complex hydrocarbon systems.
Phase diagrams Plots of pressure versus temperature or pressure
versus volumeShow the phases that exist under varying conditions. Show the phases that exist under varying conditions.
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DiagramaDiagramaDiagramaDiagrama PPPP----TTTT
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DiagramaDiagramaDiagramaDiagrama PPPP----TTTT
Vapour pressure line
Divides the regions where the
substance is a liquid from regions
where it is a gas
Conditions on the line indicate where
both liquid and gas coexist.
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DiagramaDiagramaDiagramaDiagrama PPPP----TTTT
Critical PointThe limit of the vapour
pressure line
Defines the:
Critical temperature, TCritical temperature, Tc
Critical pressure, Pc
of the pure substance
For pure component, the
limiting state for liquid and
gas to coexist.General definition:
The point at which all intensive properties of the
gas and liquid are equal
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DiagramaDiagramaDiagramaDiagrama PPPP----TTTT
Triple Point
Represents the pressure and
temperature at which solid, liquid
and vapour
co-exist under equilibrium
conditions.conditions.
Not common for Petroleum
engineers to deal with solid state.
More recently an issue in the
context of wax, ashphaltenes and
hydrates.
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DiagramaDiagramaDiagramaDiagrama PPPP----TTTT
Sublimation -Pressure
Line
Represents the pressure and
temperature at which solid exists
from the area where vapour from the area where vapour
exists.
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DiagramaDiagramaDiagramaDiagrama PPPP----TTTT
Melting Point Line
Represents the pressure and
temperature at which solid exists
from the area where liquid exists.
Of relevance to wax and hydrates
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DiagramaDiagramaDiagramaDiagrama PPPP----TTTTConsider behaviour of a PVT (pressure, volume, temperature ) cell
charged with a pure substance and the volume varied by frictionless
piston.
P1 Single phase liquid at P1
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DiagramaDiagramaDiagramaDiagrama PPPP----TTTT
Single phase liquid at P1
P1 P2
Significant pressure reduction
Small liquid volume change
Bubble point
pressure
P2P2
Small gas bubble in
equilibrium with
liquid
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DiagramaDiagramaDiagramaDiagrama PPPP----TTTT
P1
Single phase liquid at P1
P2
Bubble point
pressure P2
P3
Further volume
expansion
More gas phase.
Liquid volume decreases
Pressure remains
constantconstant
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DiagramaDiagramaDiagramaDiagrama PPPP----TTTT
P1
Single phase liquid at P1
P2
Bubble point
pressure P2
P3
Further volume
expansion
P4
Dew point
pressure P4
Small liquid drop in
equilibrium with gasequilibrium with gas
Pressure remains
constant
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DiagramaDiagramaDiagramaDiagrama PPPP----TTTT
P1
Single phase liquid at P1
P2
Bubble point
pressure P2
P3
Further volume
expansion
P4
Dew point
pressure P4
P5Further gas
expansion
Pressure reducesPressure reduces
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Diagrama P-T
P1
P2
P3P4
P5
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BehaviourBehaviourBehaviourBehaviour across the across the across the across the vapourvapourvapourvapour pressure linepressure linepressure linepressure line
From A to B via VP line
At A liquid phase
P1
Between A&B on VP
line gas & liquid phases
P3
line gas & liquid phases
At B gas phase
P5
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BehaviourBehaviourBehaviourBehaviour around the critical pointaround the critical pointaround the critical pointaround the critical point
At A liquid phase
At E compressed liquid
phase
From E to F from liquid
At G gas phase
At B gas phase
From E to F from liquid
to gas with no phase
boundary
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Beyond critical pointBeyond critical pointBeyond critical pointBeyond critical point
At 3 liquid phase ?
Dense phase fluid
From 3 to 4 a change from
liquid properties to gas
At 4 gas phase
liquid properties to gas
properties with no distinct
phase change
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DiagramaDiagramaDiagramaDiagrama PPPP----T T T T EtanoEtanoEtanoEtano
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DiagramaDiagramaDiagramaDiagrama PresinPresinPresinPresin----VolumenVolumenVolumenVolumen
1. Single phase liquid
Bubble point
first gas bubble
Dew point
P1
P2
P4
T = Tc critical temperature
Single phase region
Dew point
Last drop of liquid
All gas
P5 TTc Smooth change from liquid to gas. No
definite phase distinction.Reflects compressibilty of
liquid
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DiagramaDiagramaDiagramaDiagrama PresinPresinPresinPresin----VolumenVolumenVolumenVolumen
A series of expansions
at various constant
temperatures yield
pressure volume
diagram.
Gives the focus of the
bubble point and dew
Single phase
bubble point and dew
point values.
Liquid
GasTwo distinct phases
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DiagramaDiagramaDiagramaDiagrama PresinPresinPresinPresin----VolumenVolumenVolumenVolumen EtanoEtanoEtanoEtano
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Three Dimensional Phase Diagram for a Three Dimensional Phase Diagram for a Three Dimensional Phase Diagram for a Three Dimensional Phase Diagram for a Pure ComponentPure ComponentPure ComponentPure Component
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SistemaSistemaSistemaSistema dos dos dos dos ComponentesComponentesComponentesComponentes
Such a system is called a binary One component more volatile than the other. Components are miscible
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SistemaSistemaSistemaSistema dos dos dos dos ComponentesComponentesComponentesComponentesDiagramaDiagramaDiagramaDiagrama PresinPresinPresinPresin----VolumenVolumenVolumenVolumen
Isotherm similar to pure
component
Pressure decreases as system
goes from bubble point to dew
point
Composition of liquid and vapour
phases change from bubble point
to dew point
Physical properties function
of composition
e.g.density
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SistemaSistemaSistemaSistema dos dos dos dos ComponentesComponentesComponentesComponentesDiagramaDiagramaDiagramaDiagrama PresinPresinPresinPresin----VolumenVolumenVolumenVolumen
Compositions
Component light
Component heavy
Liquid mixture
At bubble point
Liquid Gas
At dew point
Liquid Gas
Gas mixture
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SistemaSistemaSistemaSistema dos dos dos dos ComponentesComponentesComponentesComponentes
The diagram is for
a 52.4 mole%
mixture of
N-heptane and
N-pentaneN-pentane
A finger print of
the mixture
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SistemaSistemaSistemaSistema dos dos dos dos ComponentesComponentesComponentesComponentesDiagramaDiagramaDiagramaDiagrama PresinPresinPresinPresin----TemperaturaTemperaturaTemperaturaTemperatura
Compared to a single line
representing two phase
behaviour for pure
substances,
a broad region in which
two phases co-exist
characterises 2
component systems
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SistemaSistemaSistemaSistema dos dos dos dos ComponentesComponentesComponentesComponentesDiagramaDiagramaDiagramaDiagrama PresinPresinPresinPresin----TemperaturaTemperaturaTemperaturaTemperatura
Bubble point line and dew
point line meet at critical point.
A mixture has a critical
temperature and pressure.
These values are NOT the
compositional averages of the
critical values of the pure
components.
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SistemaSistemaSistemaSistema dos dos dos dos ComponentesComponentesComponentesComponentesDiagramaDiagramaDiagramaDiagrama PresinPresinPresinPresin----TemperaturaTemperaturaTemperaturaTemperatura
Bubble Point
Within 2 phase region
proportions of liquid and gas.
These are termed quality lines
Dew point
By carrying out a series of
constant temperature expansion
phase envelope is defined
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SistemaSistemaSistemaSistema dos dos dos dos ComponentesComponentesComponentesComponentesDiagramaDiagramaDiagramaDiagrama PresinPresinPresinPresin----TemperaturaTemperaturaTemperaturaTemperatura
A specific mixture will give a
specific phase envelope.
Increase the proportion of A
and the envelope will change
shape and move to the left.
Increase the proportion of B
and the envelope will change
shape and move to the right.
PCAB much greater than PCA and PCB
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DiagramaDiagramaDiagramaDiagrama PPPP----T T T T emperatureemperatureemperatureemperatureEtanoEtanoEtanoEtano ----HeptanoHeptanoHeptanoHeptano
Critical points for various
mixtures
Pure component critical values
Locus of the mixture critical
points
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Diagrama de Fases de una mezcla de gasDiagrama de Fases de una mezcla de gasDiagrama de Fases de una mezcla de gasDiagrama de Fases de una mezcla de gasnatural natural natural natural ---- gasolina naturalgasolina naturalgasolina naturalgasolina natural
27002600
100%90%80%70%60%
50%
25002400230022002100
GAS0%
LQUIDOA % LQUID
O
L
p
c
a
LQUIDO + VAPOR (GAS)
60
50%
40%
30%
20%10%
210020001900180017001600150014001300
80 100 120 140 160TEMPERATURA, F
P
R
E
S
I
N
,
L
180 200 220 240 260
LQUIDO + VAPOR (GAS)
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PuntoPuntoPuntoPunto CriticoCriticoCriticoCriticoMezclaMezclaMezclaMezcla de HCsde HCsde HCsde HCs
Mixture of methane and
n-octane has a critical point much
greater than pure component values
Pure component critical values
Two phases exist within this
boundary
Methane is a significant component
of reservoir fluids
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CondensacinCondensacinCondensacinCondensacin RetrogradaRetrogradaRetrogradaRetrograda
Within the two phase region of our two component system there can be temperatures higher than the critical temperature and pressures higher than the critical pressure.
The cricondentherm.
Is the maximum temperature at which two phases Is the maximum temperature at which two phases can exist in equilibrium.
The cricondenbar.
Is the maximum pressure at which two phases can exist in equilibrium.
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CondensacinCondensacinCondensacinCondensacin RetrogradaRetrogradaRetrogradaRetrograda
Cricondenbar
Examine behaviour at
constant temperature
between critical temperature
and cricondentherm of
pressure decrease
1
2
At 1 single phase fluid
At 2 dew point
Cricondentherm
At 2 dew point
3
At 3 maximum
liquid4
At 4 dew point5
At 5 single gas phase
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CondensacinCondensacinCondensacinCondensacin RetrogradaRetrogradaRetrogradaRetrograda