Changes

The pressure and temperature of a reservoir fluid where the bubblepoint pressure curve meets the retrograde dewpoint pressure curve (see Figures 1 and 2), representing a unique state where all properties of the bubblepoint oil are identical to the dewpoint gas.

The pressure and temperature of a reservoir fluid where the bubblepoint pressure curve meets the retrograde dewpoint pressure curve (see Figures 1 and 2), representing a unique state where all properties of the bubblepoint oil are identical to the dewpoint gas.

[[file:petroleum-reservoir-fluid-properties_fig1.png|thumb|{{figure number|1}}Pressure-temperature phase diagram. Reservoir classification would be ''oil'' if reservoir temperature were less than 127 °F and ''gas'' if reservoir temperature were greater than [[temperature::127°F]].]]

[[file:petroleum-reservoir-fluid-properties_fig1.png|thumb|{{figure number|1}}Pressure-temperature phase diagram. Reservoir classification would be ''oil'' if reservoir temperature were less than 127 °F and ''gas'' if reservoir temperature were greater than 127°F.]]

[[file:petroleum-reservoir-fluid-properties_fig2.png|thumb|{{figure number|2}}Pressure-temperature phase diagrams of gas cap and oil fluids in a reservoir that is Initially at saturated conditions.]]

[[file:petroleum-reservoir-fluid-properties_fig2.png|thumb|{{figure number|2}}Pressure-temperature phase diagrams of gas cap and oil fluids in a reservoir that is Initially at saturated conditions.]]

|-

|-

! Component or Property

! Component or Property

! Dry Gas

! Dry Gas

! Wet Gas

! Wet Gas

|-

|-

|

|

| Bubblepoint FVF

| Bubblepoint FVF

|-

|-

|

|

| Density

| Density

|-

|-

|                Isothermal compressibility

| colspan=2 align="center" | Isothermal compressibility

|-

|-

|                Viscosity

| colspan=2 align="center" | Viscosity

|-

|-

|                K values

| colspan=2 align="center" | K values

|-

|-

|                Interfacial tension

| colspan=2 align="center" | Interfacial tension

|-

|-

|                Diffusion coefficients

| colspan=2 align="center" | Diffusion coefficients

|}

|}

''Equations of state (EOS)'' are now commonly used to calculate phase and volumetric behavior of reservoir mixtures. In particular, EOS are useful for predicting phase behavior of miscible and immiscible displacement processes resulting from the injection of gases such as carbon dioxide, nitrogen, and lean or enriched natural gas in oil and gas condensate reservoirs. EOS do not usually predict phase and volumetric behavior of reservoir mixtures accurately, thereby requiring adjustment of component properties to match experimental PVT data<ref name=pt10r36>Whitson, C. H., Brulé, M. R., 1993, Phase behavior: Society of Petroleum Engineers Monograph Series, in press.</ref>.

''Equations of state (EOS)'' are now commonly used to calculate phase and volumetric behavior of reservoir mixtures. In particular, EOS are useful for predicting phase behavior of miscible and immiscible displacement processes resulting from the injection of gases such as carbon dioxide, nitrogen, and lean or enriched natural gas in oil and gas condensate reservoirs. EOS do not usually predict phase and volumetric behavior of reservoir mixtures accurately, thereby requiring adjustment of component properties to match experimental PVT data<ref name=pt10r36>Whitson, C. H., Brulé, M. R., 1993, Phase behavior: Society of Petroleum Engineers Monograph Series, in press.</ref>.

==Laboratory Pvt experiments==

==Laboratory PVT experiments==

Experimental PVT measurements are usually obtained for (1) large oil and gas fields, (2) volatile oil and gas condensate reservoirs, and (3) reservoirs where gas injection is a potential EOR ([[enhanced oil recovery]]) method. Two types of fluid samples can be taken during production, or when a well is shut-in:

Experimental PVT measurements are usually obtained for (1) large oil and gas fields, (2) volatile oil and gas condensate reservoirs, and (3) reservoirs where gas injection is a potential EOR ([[enhanced oil recovery]]) method. Two types of fluid samples can be taken during production, or when a well is shut-in:

|+ {{table number|3}}Summary of laboratory analyses performed on reservoir oil and gas condensate systems

|+ {{table number|3}}Summary of laboratory analyses performed on reservoir oil and gas condensate systems

|-

|-

! Laboratory Analysis

! Laboratory Analysis

! Oils

! Oils

|-

|-

| Bottomhole sample

| Bottomhole sample

| <xref ref-type="table-fn" rid="FluidPropertiestblfn1"> * </xref>

| *

| <xref ref-type="table-fn" rid="FluidPropertiestblfn2"> + </xref>

| +

|-

|-

| Recombined composition

| Recombined composition

| <xref ref-type="table-fn" rid="FluidPropertiestblfn2"> + </xref>

| +

| <xref ref-type="table-fn" rid="FluidPropertiestblfn2"> + </xref>

| *

|-

|-

| C_{7 <xref ref-type="table-fn" rid="FluidPropertiestblfn2"> + </xref>} TBP distillation

| C₇₊ TBP distillation

| <xref ref-type="table-fn" rid="FluidPropertiestblfn2"> + </xref>

| +

| <xref ref-type="table-fn" rid="FluidPropertiestblfn2"> + </xref>

| +

|-

|-

| C_{7 <xref ref-type="table-fn" rid="FluidPropertiestblfn2"> + </xref>} simulated distillation

| C₇₊ simulated distillation

| <xref ref-type="table-fn" rid="FluidPropertiestblfn2"> + </xref>

| +

| <xref ref-type="table-fn" rid="FluidPropertiestblfn2"> + </xref>

| +

|-

|-

| Constant composition expansion

| Constant composition expansion

| <xref ref-type="table-fn" rid="FluidPropertiestblfn1"> * </xref>

| *

| <xref ref-type="table-fn" rid="FluidPropertiestblfn1"> * </xref>

| *

|-

|-

| Multistage surface separation

| Multistage surface separation

| <xref ref-type="table-fn" rid="FluidPropertiestblfn1"> * </xref>

| *

| <xref ref-type="table-fn" rid="FluidPropertiestblfn2"> + </xref>

| +

|-

|-

| Differential liberation

| Differential liberation

| <xref ref-type="table-fn" rid="FluidPropertiestblfn1"> * </xref>

| *

| <xref ref-type="table-fn" rid="FluidPropertiestblfn3"> – </xref>

| –

|-

|-

| Constant volume depletion

| Constant volume depletion

| <xref ref-type="table-fn" rid="FluidPropertiestblfn2"> + </xref>

| +

| <xref ref-type="table-fn" rid="FluidPropertiestblfn1"> * </xref>

| *

|-

|-

| Multicontact gas injection

| Multicontact gas injection

| <xref ref-type="table-fn" rid="FluidPropertiestblfn2"> + </xref>

| +

| <xref ref-type="table-fn" rid="FluidPropertiestblfn2"> + </xref>

| +

|}

|}

Compositional analyses are used to describe the reservoir fluid makeup on a component basis, including calculation of BTU (energy content) of gases, optimization of separator conditions for liquid yield, and characterization of an EOS for compositional simulation. Differential liberation and constant volume depletion experiments are designed to provide quantitative information about the volumetric behavior of oil and gas condensate reservoirs during pressure depletion. The multistage separator test is used together with differential liberation and constant volume depletion data to calculate black oil properties ''R''_s, ''B''_o, ''B''_g, and ''r''_s. Multicontact gas injection experiments provide important volumetric and compositional data that can be used to “tune” an equation of state (or alternative) model for simulation of gas injection processes.

Compositional analyses are used to describe the reservoir fluid makeup on a component basis, including calculation of BTU (energy content) of gases, optimization of separator conditions for liquid yield, and characterization of an EOS for compositional simulation. Differential liberation and constant volume depletion experiments are designed to provide quantitative information about the volumetric behavior of oil and gas condensate reservoirs during pressure depletion. The multistage separator test is used together with differential liberation and constant volume depletion data to calculate black oil properties ''R''_s, ''B''_o, ''B''_g, and ''r''_s. Multicontact gas injection experiments provide important volumetric and compositional data that can be used to “tune” an equation of state (or alternative) model for simulation of gas injection processes.