Methods to determine conditions of a hydrocarbon reservoir

Patent metadata

Field	Value
Publication number	US-10663618-B2
Application number	US-201715634793-A
Country	US
Kind code	B2
Filing date	Jun 27, 2017
Priority date	Jul 1, 2016
Publication date	May 26, 2020
Grant date	May 26, 2020

Abstract

A method of identifying in situ conditions of a hydrocarbon reservoir is disclosed. The method comprises, obtaining a sample from an area of interest, such as a sediment sample or water column sample near a hydrocarbon seep; analyzing the sample to detect lipid, protein, and/or nucleic acid signatures that are indicative of the Thermotogales order; identifying the relative abundance of the different genera and/or species of the Thermotogales present in the sample to generate a taxonomy signature of the sample; and then using the taxonomy signature to determine conditions, such as temperature, of the hydrocarbon reservoir.

First claim

The invention claimed is:

1. A method of determining one or more conditions of a hydrocarbon reservoir comprising:
(a) obtaining a sample near a subsea hydrocarbon seep associated with the hydrocarbon reservoir, wherein the sample is obtained from a location that is within a radius of 150 meters from the center of the location where the seep is emanating from the seafloor;
(b) extracting one or more of nucleic acids from the sample;
(c) analyzing the extracted nucleic acids to identify signatures that are indicative of organisms from the Thermotogales order;
(d) identifying the relative abundance of different genera or species of Thermotogales present in the sample and assigning a taxonomy signature to the sample;
(e) using the taxonomy signature to determine the temperature of the hydrocarbon reservoir, wherein the hydrocarbon reservoir is identified as having a temperature of less than 60° C. when the taxonomy signature of the sample indicates that the sample contains 50-100% of microbes from the genera of Petrotoga, Kosmotoga , or a mixture thereof, wherein the hydrocarbon reservoir is identified as having a temperature of from 60° C. to 80° C. when the taxonomy signature of the sample indicates that the sample contains 40 to 100% of microbes from the genera of Thermotoga , less than 30% of microbes from the genera of Petrotoga , and less than 30% of microbes from the genera of Kosmotoga , and wherein the hydrocarbon reservoir is identified as having a temperature of greater than 80° C. when the taxonomy signature of the sample indicates that the sample contains less than 30% of microbes from the genera of Thermotoga , less than 30% of microbes from the genera of Petrotoga , less than 30% of microbes from the genera of Kosmotoga , and from 30-100% of the microbes that are Archaea.

2. The method of claim 1 , wherein the sample is a fluid sample obtained from a water column near the hydrocarbon seep.

3. The method of claim 1 , wherein the sample is a sediment sample obtained from the seafloor near the hydrocarbon seep.

4. The method of claim 1 , wherein the sample is obtained from a location that is within a radius of 10 meters from the center of the location where the seep is emanating from the seafloor.

5. The method of claim 1 , wherein the sample is obtained from a location that is within a radius of 3 meters from the center of the location where the seep is emanating from the seafloor.

6. The method of claim 1 , further comprising preserving the obtained sample at a temperature at or less than −60° C. until the sample is ready to have the one or more nucleic acids extracted.

7. The method of claim 1 , wherein the samples are analyzed to identify nucleic acid signatures that are indicative of organisms from the family Thermotogaceae.

8. The method of claim 1 , wherein the samples are analyzed to identify nucleic acid signatures that are indicative of organisms from the genera Defluviitoga, Fervidobacterium, Geotoga, Kosmotoga, Mariniloga, Mesotoga, Oceanotoga, Petrotoga, Thermopalliu, Thermosipho , and Thermotoga.

9. The method of claim 1 , wherein the samples are analyzed to identify nucleic acid signatures that are indicative of organisms from the genera Petrotoga, Kosmotoga , and Thermotoga.

10. The method of claim 1 , wherein the taxonomy signature from the sample is calibrated by comparing the signature to a signature obtained from a reference sample that is obtained away from the hydrocarbon seep.

11. The method of claim 10 , further comprising:
obtaining a second sample from an area not associated with the hydrocarbon reservoir;
extracting one or more of proteins, lipids, or nucleic acids from the second sample;
analyzing the extracted proteins, lipids, or nucleic acids from the second sample to identify signatures that are indicative of organisms from the Thermotogales order;
identifying the relative abundance of different genera or species of Thermotogales present in the second sample and assigning a taxonomy signature to the second sample;
comparing the taxonomy signature of the second sample with the taxonomy signature of the sample taken from the hydrocarbon seep;
using the compared taxonomy signature to determine the temperature of the hydrocarbon reservoir.

12. The method of claim 10 , wherein the reference sample is obtained at a location that is at least 200 meters away from the center of the location where the seep is emanating from the surface.

13. The method of claim 1 , wherein the nucleic acid analysis comprises one or more of DNA analysis, RNA analysis, and metagenomics.

14. The method of claim 1 , further comprising using the determined temperature to determine the depth of the hydrocarbon reservoir.

15. The method of claim 14 , wherein determining the depth of the hydrocarbon reservoir comprises using a geothermal gradient to determine the depth from the determined temperature.

16. The method of claim 14 , further comprising conducting a seismic survey of the hydrocarbon reservoir, wherein the seismic survey is targeted at the determined depth.

17. The method of claim 14 , further comprising using the determined depth to interpret seismic data of the hydrocarbon reservoir.

Assignees

• Exxonmobil Upstream Res Co

Inventors

• Summers Zarath M
• N'Guessan A Lucie
• Regberg Aaron B

Classifications

• G01N33/24

  Earth materials (G01N33/42 takes precedence) · CPC title

• C12Q2600/158

  Expression markers · CPC title

• C12Q1/64 Primary

  Geomicrobiological testing, e.g. for petroleum · CPC title

• C12Q1/689

  for bacteria · CPC title

• G01N33/2823

  Raw oil, drilling fluid or polyphasic mixtures · CPC title