High accuracy contamination estimation in hydrocarbon samples using GC×GC

• US 7,805,979 B2
• Filed: 10/22/2007
• Issued: 10/05/2010
• Est. Priority Date: 10/25/2006
• Status: Expired due to Fees

• Current Assignee: Schlumberger Technology Corporation (Schlumberger NV), Woods Hole Oceanographic Institution
• Original Assignee: Schlumberger Technology Corporation (Schlumberger NV), Woods Hole Oceanographic Institution
• Inventors: Nelson, Robert K., Reddy, Christopher Michael, Mullins, Oliver C., Raghuraman, Bhavani
• Primary Examiner(s): Williams; Hezron
• Assistant Examiner(s): SHABMAN, MARK A
• Application Number:
  US11/876,185
• Publication Number:
  US 20080105032A1
• Time in Patent Office: 1,079 Days
• Field of Search: 73/234.1
• US Class Current: 73/23.38
• CPC Class Codes: E21B 49/08 Obtaining fluid samples or testing fluids, in boreholes or wells
• CPC Class Codes: G01N 2030/025 Gas chromatography
• CPC Class Codes: G01N 30/463 for multidimensional chromatography
• 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
• CPC Class Codes: G01N 33/2835 specific substances contained in the oil or fuel

Abstract

A method of estimating contamination of oil based mud filtrate in a hydrocarbon sample. The method comprising the steps of obtaining a hydrocarbon sample contaminated with oil based mud filtrate, then analyzing the contaminated hydrocarbon sample using two-dimensional gas chromatography (GC×GC). The method further comprises identifying one or more unique component or tracer in the oil based mud filtrate in the contaminated hydrocarbon sample. Finally, the method comprises of summing the peak volumes of the one or more unique component or tracer, relative to the peak volumes of a clean hydrocarbon sample.

Claims

1. A method of analyzing contamination of oil based mud filtrate in a hydrocarbon sample, the method comprising the steps of:

a) obtaining a hydrocarbon sample contaminated with oil based mud filtrate wherein the oil based mud filtrate is selected from the group consisting of a non-synthetic oil based mud filtrate or a synthetic oil based mud filtrate;

b) analyzing the contaminated hydrocarbon sample using two-dimensional gas chromatography (GC×

GC);

c) identifying one or more unique component or tracer in the oil based mud filtrate in the contaminated hydrocarbon sample; and

d) summing the peak volumes of the one or more unique component or tracer, relative to the peak volumes of a clean hydrocarbon sample.

2. The method of claim 1, wherein at least one unique component of the one or more unique component is from the synthetic oil based component.

3. The method of claim 1, wherein at least one tracer of the one or more tracer is added to the non-synthetic oil based mud filtrate.

4. The method of claim 1, wherein the contamination of oil based mud filtrate in the hydrocarbon sample is greater than about 0.1%.

5. The method of claim 1, wherein the contamination of oil based mud filtrate in the hydrocarbon sample is from about 0.1% to about 10%.

6. The method of claim 1, wherein two-dimensional gas chromatography (GC×

GC) has a greater resolving power in identifying one or more unique component and tracer compared to a one-dimensional gas chromatography.

7. The method of claim 1, wherein there are at least two or more dimension separations.

8. The method of claim 1, wherein the GC×

GC involves a first dimension separation using a non-polar phase; and

a second dimension separation using a polar phase.

9. The method of claim 8, wherein non-polar phase separates petroleum compounds by volatility differences;

and the polar phase separates first dimension co-eluters by polarity differences.

10. The method of claim 9, wherein the non-polar phase is a polydimethylsiloxane column;

and the polar phase is a 50% phenyl-substituted polydimethylsiloxane column.

11. The method of clam 1, wherein the unique component or tracer in the oil based mud filtrate is selected from the group consisting of an iso-olefin, a liner alpha olefin, a poly-alpha olefin or ester.

12. The method of claim 11, wherein the iso-olefin is a C₁₆ to C₂₀ alkene.

13. A method of separating and analyzing contamination of drilling fluid in a hydrocarbon sample, the method comprising the steps of:

a) obtaining a hydrocarbon sample contaminated with drilling fluid;

b) analyzing the contaminated hydrocarbon sample using two-dimensional gas chromatography (GC×

GC), wherein the contaminated hydrocarbon sample is subject to two different stationary phase selectivities;

c) identifying one or more unique component or tracer in the drilling fluid in the contaminated hydrocarbon sample; and

d) summing the peak volumes of the one or more unique component or tracer, relative to the peak volumes of a clean hydrocarbon sample.

14. The method of claim 13, wherein the drilling fluid is selected from the group consisting of an oil based mud filtrate, a non-synthetic oil based mud filtrate, a synthetic oil based mud filtrate or some combination thereof.

15. The method of claim 14, wherein the one or more unique component is from the synthetic oil based mud filtrate.

16. The method of claim 14, wherein the method includes at least one tracer of the one or more tracer that is added to the non-synthetic oil based mud filtrate.

17. The method of claim 13, wherein the two different stationary phase selectivities involves a first dimension separation using a non-polar phase;

and a second dimension separation using a polar phase.

18. The method of claim 17, wherein non-polar phase separates petroleum compounds by volatility differences;

and the polar phase separates first dimension co-eluters by polarity differences.

19. The method of claim 18, wherein the non-polar phase is a polydimethylsiloxane column;

and the polar phase is a 50% phenyl-substituted polydimethylsiloxane column.

20. The method of claim 13, wherein the contamination of drilling fluid in the hydrocarbon sample is greater than about 0.1%.

21. The method of clam 13, wherein the unique component or tracer in the drilling fluid is selected from the group consisting of an iso-olefin, a liner alpha olefin, a poly-alpha olefin or ester.

22. The method of claim 21, wherein the iso-olefin is a C₁₆ to C₂₀ alkene.