Methods and apparatus for oil composition determination

• US 7,458,258 B2
• Filed: 12/16/2005
• Issued: 12/02/2008
• Est. Priority Date: 12/16/2005
• Status: Active Grant

• Current Assignee: Schlumberger Technology Corporation (SLB)
• Original Assignee: Schlumberger Technology Corporation (SLB)
• Inventors: Mullins, Oliver C., Fujisawa, Go, Carnegie, Andrew, Xian, ChengGang, Dong, ChengLi
• Primary Examiner(s): Williams; Hezron
• Assistant Examiner(s): Frank; Rodney T
• Application Number:
  US11/303,695
• Publication Number:
  US 20070137292A1
• Time in Patent Office: 1,082 Days
• Field of Search: 731/521.8, 731/520.1
• US Class Current: 73/152.18
• CPC Class Codes: G01N 21/314 with comparison of measurements at specific and non-specific wavelengths dual wavelength spectrometry G01J3/427
• CPC Class Codes: G01N 21/359 using near infrared light
• CPC Class Codes: G01N 21/80 Indicating pH value
• CPC Class Codes: G01N 33/2823 Raw oil, drilling fluid or polyphasic mixtures
• CPC Class Codes: G01N 33/2841 Gas in oils, e.g. hydrogen in insulating oils

Abstract

A method for determining properties of a formation fluid is provided and includes: obtaining fluid data related to Carbon-Hydrogen molecular bonds in C6+ from a fluid analyzer; and considering the fluid data to calculate mass fractions of hydrocarbon flowing through the fluid analyzer. The method further includes computing gas-oil-ratio of hydrocarbon based on the mass fractions of hydrocarbon. Another method for determining a gas-oil-ratio of a formation fluid includes: obtaining fluid data related to Carbon-Hydrogen molecular bonds in C6+ from a fluid analyzer; considering the fluid data to derive mass fractions of gas and oil; and computing gas-oil-ratio of hydrocarbon based on the derived mass fractions.

Claims

1. A method for determining properties of a formation fluid, comprising:

a) obtaining a first fluid data related to Carbon-Hydrogen molecular bonds in C6+ from a fluid analyzer;

b) obtaining a second fluid data related to Oxygen-Hydrogen bonds of water molecules from the fluid analyzer; and

c) considering said first and second fluid data to calculate mass fractions of hydrocarbon flowing through the fluid analyzer.

2. The method of claim 1, wherein said considering said fluid data is based on assumption that the total hydrocarbon fraction from the fluid analyzer at a specific time is 1.0 in case of the absence of water in the flowline.

3. The method of claim 1, wherein said considering said fluid data is based on assumption that the total fraction of hydrocarbon/water mixture at a specific time is 1.0 in case of oil and water mixing flow in the flowline.

4. The method of claim 1, wherein the mass fractions of hydrocarbon are C1-C5 and C6+ mass fractions.

5. The method of claim 1 further comprising deriving a correlation related to said mass fractions of hydrocarbon.

6. The method of claim 1 further comprising computing gas-oil-ratio of hydrocarbon based on said mass fractions of hydrocarbon.

7. The method of claim 6, wherein said computing gas-oil-ratio is based on assumption that the non-water formation fluid has negligible amounts molecular bonds that are not Carbon-Hydrogen, where compounds that contain such negligible amounts molecular bonds are N2, H2S, CO2 and asphaltenes.

8. The method of claim 1, wherein the fluid analyzer is Optical Fluid Analyzer, Live Fluid Analyzer, or Advanced Fluid Analyzer.

9. A fluid analyzer comprising:

a) a sensor for measuring fluid data related to Carbon-Hydrogen molecular bonds in C6+ and further measuring fluid data related to Oxygen-Hydrogen bonds of water molecules; and

b) a processor for calculating mass fractions of hydrocarbon flowing through the fluid analyzer based on the measured fluid data.

10. The fluid analyzer of claim 9, wherein the mass fractions of hydrocarbon are C1-C5 and C6+ mass fractions.

11. The fluid analyzer of claim 9, wherein the processor further computes gas-oil-ratio of hydrocarbon based on said mass fractions of hydrocarbon.

12. A method for determining a gas-oil-ratio of a formation fluid, comprising:

a) obtaining a first fluid data related to Carbon-Hydrogen molecular bonds in C6+ and a second fluid data related to Oxygen-Hydrogen bonds of water molecules from a fluid analyzer;

b) considering said first and second fluid data to derive mass fractions of gas and oil; and

c) computing gas-oil-ratio of hydrocarbon based on said derived mass fractions.

13. The method of claim 12, wherein said computing gas-oil-ratio is based on assumption that the non-water formation fluid has negligible amounts molecular bonds that are not Carbon-Hydrogen, where compounds that contain such negligible amounts molecular bonds are N2, H2S, CO2 and asphaltenes.

14. The method of claim 12, wherein the fluid analyzer is Optical Fluid Analyzer, Live Fluid Analyzer, or Advanced Fluid Analyzer.