Methods and apparatus for characterization of petroleum fluid and applications thereof

• US 7,920,970 B2
• Filed: 09/11/2008
• Issued: 04/05/2011
• Est. Priority Date: 01/24/2008
• Status: Active Grant

• Current Assignee: Schlumberger Technology Corporation (Schlumberger NV)
• Original Assignee: Schlumberger Technology Corporation (Schlumberger NV)
• Inventors: Zuo, Youxiang (Julian), Zhu, Jiabao (Jack), Muhammad, Moin, Zhang, Dingan (Dan)
• Primary Examiner(s): Nghiem; Michael P
• Assistant Examiner(s): Desta; Elias
• Application Number:
  US12/209,050
• Publication Number:
  US 20090192768A1
• Time in Patent Office: 936 Days
• Field of Search: 731/522.4, 166/244.1, 166/336, 250/255, 250/269.1, 702 6- 13, 703/10
• US Class Current: 702/11
• CPC Class Codes: G01N 33/2823 raw oil, drilling fluid or polyphasic mixtures hydrocarbon content of earth materials G01N33/241; prospecting G01V; drilling per se E21B

Abstract

An improved method and system for characterizing the compositional components of a hydrocarbon reservoir of interest and analyzing fluid properties of the reservoir of interest based upon its compositional components.

Claims

1. A method for characterizing one or more properties of a multi-component petroleum fluid comprising:

(a) measuring downhole with a downhole fluid analysis tool data representing at least one property for a group of components of the multi-component petroleum fluid and storing the data in a non-transitory, computer-readable memory, said at least one property for the group of components comprising weight percentage of the group of components;

(b) using a computer processor and software stored in the computer-readable memory to derive at least one property for the respective components of the group of components based on the data stored in (a), wherein said at least one property comprises weight percentages for the respective components of the group, and an empirical relation derived from analysis of a pressure-volume-temperature (PVT) database, wherein said empirical relation follows a linear function of carbon number for the respective components of the group and is based on weighing factors calculated according to the equation, ψ

_i=A*CN_i+β

, where i varies over a range of integers corresponding to the group of single carbon number components of the group of components, ψ

_i is the weighing factor for the i^th single carbon number component in the group of components, A and B are determined by a regression analysis of the PVT database, and CN_i is the carbon number for the i^th single carbon number component in the group of components;

(c) using the computer processor and software and the at least one property for the respective components of the group derived in (b) to estimate or predict one or more properties of said multi-component fluid; and

(d) outputting the results obtained in (c) for presentation to a user.

2. A method according to claim 1, wherein the components of the group comprise single carbon number alkanes.

3. A method according to claim 1, wherein said empirical relation is derived by normalizing said weighing factors.

4. A method according to claim 1, further comprising:

(e) deriving at least one property for at least one particular component of the multi-component petroleum fluid based on at least one property for a respective component of the group derived in (b) and an empirical relation derived from analysis of the PVT database.

5. A method according to claim 4, wherein the at least one particular component and respective component in (e) are single carbon number hydrocarbon components with the particular component having a larger carbon number than that of the respective component.

7. A method according to claim 1, wherein in (c), the at least one property derived in (b) is used to generate an equation of state model for predicting one or more properties of said multi-component fluid.

8. A method according to claim 7, wherein the equation of state model predicts properties selected from the group including:

i) PVT properties comprising phase envelope, pressure-temperature (PT) flash, constant composition expansion (CCE), differential liberation (DL), constant volume depletion (CVD), separation, viscosity, oil and gas formation volume factors (FVF), and compressibility factor;

ii) compositional and property gradients;

iii) gas hydrate formation;

iv) wax precipitation;

v) asphaltene precipitation; and

vi) scaling.

6. A method for characterizing one or more properties of a multi-component petroleum fluid comprising:

(a) measuring downhole with a downhole fluid analysis tool data representing at least one property for a group of components of the multi-component petroleum fluid and storing the data in a non-transitory, computer-readable memory, said at least one property for the group of components comprising weight percentage of the group of components;

(b) using a computer processor and software stored in the computer-readable memory to derive at least one property for the respective components of the group of components based on the data stored in (a) and an empirical relation derived from analysis of a pressure-volume-temperature (PVT) database, said at least one property for the respective components of the group of components comprising weight percentages for the respective components;

(c) deriving at least one property for at least one particular component of the multi-component petroleum fluid based on at least one property for a respective component of the group of components derived in (b) and an empirical relation derived from analysis of the PVT database, wherein said at least one property includes weight percentage of the particular component,

(d) wherein the empirical relation follows a linear function of the form;

W_CT=C*W_Cx, where W_Cx is a weight percentage for a single carbon number component derived in (b), C is a constant, and W_CT is the weight percentage of the particular component derived in (c)

(e) using the computer processor and software and the at least one property for the respective components of the group of components derived in (b) to estimate or predict one or more properties of said multi-component fluid;

(f) outputting the results obtained in (e) for presentation to a user.

9. A method for characterizing one or more properties of a multi-component petroleum fluid comprising:

(a) using a computer processor and software stored in a non-transitory, computer-readable memory to characterize at least one property for a group of components of the multi-component petroleum fluid, the at least one property of the group including molecular weight and specific gravity, wherein molecular weight is derived by an empirical relation based on gas-oil ratio (GOR) data, and the specific gravity is derived from the molecular weight;

(b) using the computer processor and software to derive at least one property for the respective components of the group based on the at least one property for the group of components characterized in (a);

(c) using the computer processor and software and the at least one property for the respective components of the group derived in (b) to estimate or predict one or more properties of said multi-component fluid; and

(d) outputting the results obtained in (c) for presentation to a user.

10. A method according to claim 9, wherein the GOR data is measured by a downhole fluid analysis tool.

11. A method according to claim 9, wherein the OUR data is estimated from an empirical relation based on weight percentages of one or more alkane components of the multi-component petroleum fluid.

12. A method according to claim 11, wherein the empirical relation for estimating GOR is based on analysis of a pressure-volume-temperature (PVT) database.

13. A method according to claim 12, wherein the empirical relation for estimating GOR has the form

14. A method according to claim 12, wherein the empirical relation for estimating GOR has the form

15. A method according to claim 9, wherein the empirical relation for deriving molecular weight (MW) has the form

MW=α

₁*GOR<sup>α

2</sup>

where α

₁ and α

₂ are derived by regression analysis carried out over a pressure-volume-temperature (PVT) database.

16. A method according to claim 9, wherein the empirical relation for deriving molecular weight (MW) has the form

MW=β

₁*GOR+β

₂

where β

₁ and β

₂ are derived by regression analysis carried out over a pressure-volume-temperature (PVT) database.

17. A method according to claim 9, wherein specific gravity (SG) is derived from molecular weight (MW) by an equation of the form

SG=η

₁ ln(MW)+η

₂

where η

₁,η

₂ are derived by analysis of a pressure-volume-temperature (PVT) database.

18. A method according to claim 9, wherein the properties of the respective components of the group derived in (b) include weight percentages for the respective components of the group.

19. A method according to claim 18, wherein the weight percentages for the respective components of the group are derived by solving a series of equations of the form

20. A method according to claim 9, wherein in (c), the at least one property derived in (b) is used to generate an equation of state model for predicting one or more properties of said multi-component fluid.

21. A method according to claim 20, wherein the equation of state model predicts properties selected from the group including:

i) pressure-volume-temperature (PVT) properties comprising phase envelope, pressure-temperature (PT) flash, constant composition expansion (CCE), differential liberation (DL), constant volume depletion (CVD), separation, viscosity, oil and gas formation volume factors (FVF) and compressibility factor;

ii) compositional and property gradients;

iii) gas hydrate formation;

iv) wax precipitation;

v) asphaltene precipitation; and

vi) scaling.

22. A computer processing system for characterizing one or more properties of a multi-component petroleum fluid, the system comprising:

(a) non-transitory memory, processor, and software means for characterizing at least one property for a group of components of the multi-component petroleum fluid, the at least one property of the group including molecular weight and specific gravity, wherein molecular weight is derived by an empirical relation based on gas-oil ratio (GOR) data, and the specific gravity is derived from the molecular weight;

(b) processor and software means for deriving at least one property for the respective components of the group based on the at least property for the group of components characterized in (a); and

(c) processor and software means for using the at least one property for the respective components of the group derived in (b) to estimate or predict one or more properties of said multi-component fluid.

23. A computer processing system according to claim 22, wherein the GOR data is measured by a downhole fluid analysis tool.

24. A computer processing system according to claim 22, wherein the GOR data is estimated from an empirical relation based on weight percentages of one or more alkane components of the multi-component petroleum fluid.

25. A non-transitory, computer-readable medium containing computer instructions stored therein for causing a computer processor to perform a sequence of instructions for performing method steps for characterizing one or more properties of a multi-component petroleum fluid, the method steps comprising:

(a) characterizing at least one property for a group of components of the multi-component petroleum fluid, the at least one property of the group including molecular weight and specific gravity, wherein molecular weight is derived by an empirical relation based on gas-oil ratio (GOR) data, and the specific gravity is derived from the molecular weight;

(b) deriving at least one property for the respective components of the group based on the at least property for the group of components characterized in (a); and

(c) using the at least one property for the respective components of the group derived in (b) to estimate or predict one or more properties of said multi-component fluid.

26. A non-transitory, computer-readable medium according to claim 25, wherein the GOR data is measured by a downhole fluid analysis tool.

27. A non-transitory, computer-readable medium according to claim 25, wherein the GOR data is estimated from an empirical relation based on weight percentages of one or more alkane components of the multi-component petroleum fluid.