Sampling techniques to detect hydrocarbon seepage

Patent metadata

Field	Value
Publication number	US-10280747-B2
Application number	US-201615158290-A
Country	US
Kind code	B2
Filing date	May 18, 2016
Priority date	May 20, 2015
Publication date	May 7, 2019
Grant date	May 7, 2019

Abstract

Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for detecting seepage of hydrocarbons in subterranean zones. In one aspect, a method includes detecting hydrocarbon seepage at multiple different sampling depths from a surface in a surveyed geographic region, comparing each of the hydrocarbon seepage at the multiple different sampling depths, wherein hydrocarbon seepage at a reference depth is known, and determining hydrocarbon seepage through the surveyed geographic region based on a result of the comparison.

First claim

What is claimed is:

1. A method of sampling a geographic region for hydrocarbon seepage, the method comprising:
detecting, by a first hydrocarbon sensor, hydrocarbon seepage at a first sampling depth from a surface in a surveyed geographic region;
detecting, by a second hydrocarbon sensor, hydrocarbon seepage at a second sampling depth from the surface, the second sampling depth deeper than the first sampling depth;
detecting, by a third hydrocarbon sensor, hydrocarbon seepage at a third sampling depth from the surface, the third sampling depth deeper than the second sampling depth;
comparing, by a processor, each of the hydrocarbon seepage at the first sampling depth, the hydrocarbon seepage at the second sampling depth, and the hydrocarbon seepage at the third sampling depth with hydrocarbon seepage at a reference depth deeper than the first, second and third sampling depths, wherein hydrocarbon seepage at the reference depth is known; and
determining, by the processor, hydrocarbon seepage through the surveyed geographic region based on a result of comparing each of the hydrocarbon seepage at the first sampling depth, the hydrocarbon seepage at the second sampling depth, and the hydrocarbon seepage at the third sampling depth with the hydrocarbon seepage at the reference depth.

2. The method of claim 1 , wherein the first sampling depth is about 1.0 meter from the surface.

3. The method of claim 1 , wherein the second sampling depth is about 5.0 meter from the surface.

4. The method of claim 1 , wherein the third sampling depth is greater than 10.0 meters from the surface.

5. The method of claim 1 , further comprising analyzing, based on the hydrocarbon seepage the first sampling depth, the hydrocarbon seepage at the second sampling depth, and the hydrocarbon seepage at the third sampling depth, a relationship between polar compounds and non-polar compounds included in the hydrocarbon.

6. The method of claim 1 , further comprising initiating drilling at a location in the surveyed geographic region, the location selected based on the determined hydrocarbon seepage through the surveyed geographic region.

7. The method of claim 1 , wherein the hydrocarbon seepage at the first sampling depth, the hydrocarbon seepage at the second sampling depth and the hydrocarbon seepage at the third sampling depth are detected at a first time instant, and wherein the method further comprises:
detecting, at a second time instant after the first time instant, hydrocarbon seepage at the first sampling depth;
detecting, at the second time instant, hydrocarbon seepage at a second sampling depth from the surface, the second sampling depth deeper than the first sampling depth;
detecting, at the second time instant, hydrocarbon seepage at a third sampling depth from the surface, the third sampling depth deeper than the second sampling depth; and
comparing, by the processor, each of the hydrocarbon seepage at the first sampling depth detected at the second time instant, the hydrocarbon seepage at the second sampling depth detected at the second time instant, and the hydrocarbon seepage at the third sampling depth detected at the second time instant with hydrocarbon seepage at the reference depth determined at the second time instant.

8. The method of claim 7 , further comprising determining hydrocarbon seepage through the surveyed geographic region as a function of time based on a result of the comparing at the first time instant and the comparing at the second time instant.

9. The method of claim 1 , wherein detecting hydrocarbon seepage at the first sampling depth comprises, detecting hydrocarbon seepage at the second sampling depth and detecting hydrocarbon seepage at the third sampling depth comprises:
positioning a first plurality of hydrocarbon sensors at the first sampling depth;
positioning a second plurality of hydrocarbon sensors at the second sampling depth; and
positioning a third plurality of hydrocarbon sensors at the third sampling depth, wherein the first plurality of hydrocarbon sensors, the second plurality of hydrocarbon sensors and the third plurality of hydrocarbon sensors are configured to detect hydrocarbons at the first sampling depth, the second sampling depth and the third sampling depth, respectively.

10. The method of claim 9 , wherein positioning the first plurality of hydrocarbon sensors at the first sampling depth comprises positioning the first plurality of hydrocarbon sensors in a two-dimensional array at the first sampling depth.

11. The method of claim 9 , wherein positioning the second plurality of hydrocarbon sensors at the second sampling depth comprises positioning the second plurality of hydrocarbon sensors in a two-dimensional array at the second sampling depth.

12. The method of claim 9 , wherein positioning the third plurality of hydrocarbon sensors at the third sampling depth comprises positioning the third plurality of hydrocarbon sensors in a two-dimensional array at the third sampling depth.

13. The method of claim 1 , further comprising positioning a reference hydrocarbon sensor at the reference depth, the reference hydrocarbon sensor configured to detect hydrocarbons at the reference depth.

14. The method of claim 13 , wherein the reference depth is within a hydrocarbon reservoir in the surveyed geographic region.

15. The method of claim 13 , wherein comparing each of the hydrocarbon seepage at the first sampling depth, the hydrocarbon seepage at the second sampling depth, and the hydrocarbon seepage at the third sampling depth with hydrocarbon seepage at a reference depth deeper than the first, second and third sampling depths comprises detecting hydrocarbon seepage at the reference depth.

16. The method of claim 13 , wherein comparing each of the hydrocarbon seepage at the first sampling depth, the hydrocarbon seepage at the second sampling depth, and the hydrocarbon seepage at the third sampling depth with hydrocarbon seepage at a reference depth deeper than the first, second and third sampling depths comprises:
determining, by the processor, a reference hydrocarbon seepage signal that represents the hydrocarbon seepage at the reference depth;
determining, by the processor, a first hydrocarbon seepage signal that represents the hydrocarbon seepage at the first sampling depth;
determining, by the processor, a second hydrocarbon seepage signal that represents the hydrocarbon seepage at the second sampling depth;
determining, by the processor, a third hydrocarbon seepage signal that represents the hydrocarbon seepage at the third sampling depth;
subtracting, by the processor, the first hydrocarbon seepage signal from the reference hydrocarbon seepage signal;
subtracting, by the processor, the second hydrocarbon seepage signal from the reference hydrocarbon seepage signal; and
subtracting, by the processor, the third hydrocarbon seepage signal from the reference hydrocarbon seepage signal.

Assignees

• Saudi Arabian Oil Co

Inventors

• Abuali Mahdi
• Almarhoon Maher I
• Arouri Khaled

Classifications

• G01N2001/021

  Correlating sampling sites with geographical information, e.g. GPS · CPC title

• E21B49/08 Primary

  Obtaining fluid samples or testing fluids, in boreholes or wells · CPC title

• G01V9/007

  by detecting gases or particles representative of underground layers at or near the surface (analysing earth materials G01N33/24; analysing gases per se G01N) · CPC title

• G01N1/08

  involving an extracting tool, e.g. core bit · CPC title

• G01N1/2294

  Sampling soil gases or the like · CPC title