Methods to determine conditions of a hydrocarbon reservoir

Patent metadata

Field	Value
Publication number	US-10570735-B2
Application number	US-201715634783-A
Country	US
Kind code	B2
Filing date	Jun 27, 2017
Priority date	Jul 1, 2016
Publication date	Feb 25, 2020
Grant date	Feb 25, 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 nucleic acid signatures that are indicative of microbes associated with hypersaline aquifers; and using the signature to determine the salinity 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 nucleic acids from the sample;
(c) analyzing the extracted nucleic acids to identify signatures that are indicative of organisms from one or more genera of Marinobacter, Desulfovibrio, Methanohalophilus , and Halanaerobium;
(d) using the identified signatures to determine the salinity of the hydrocarbon reservoir, wherein the hydrocarbon reservoir is identified as having a total dissolved solids content of less than 50,000 ppm when the identified signatures indicate that the sample contains less than 10% of organisms from the genera of Marinobacter, Desulfovibrio, Halanaerobium , and Methanohalophilus , wherein the hydrocarbon reservoir is identified as having a total dissolved solids content of from 50,000 ppm to 100,000 ppm when the identified signatures indicate that the sample contains from 10% to 30% of organisms from the genera of Marinobacter, Desulfovibrio, Halanaerobium , and Methanohalophilus , and wherein the hydrocarbon reservoir is identified as having a total dissolved solids content of greater than 100,000 ppm when the identified signatures indicate that the sample contains greater than 30% of organisms from the genera of Marinobacter, Desulfovibrio, Halanaerobium , and Methanohalophilus ; and
(e) using the determined salinity to interpret seismic data of the hydrocarbon reservoir.

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

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

4. 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.

5. 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 nucleic acids extracted.

6. The method of claim 1 , wherein the samples are analyzed to identify nucleic acid signatures that are indicative of organisms from one or more of the species of Desulfovibrio gabonensis, Desulfovibrio bastinii, Desulfovibrio capillatus, Desulfovibrio gacillis, Desulfovibrio longus, Halanaerobium salsuginsis, Halanaerobium congolense, Marinobacter aquaeolei , and Marinobacter hydrocarbonoclasticus.

7. The method of claim 1 , where the nucleic acid 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.

8. The method of claim 7 , further comprising:
obtaining a second sample from an area not associated with the hydrocarbon reservoir; extracting nucleic acids from the second sample;
analyzing the extracted nucleic acids to identify signatures that are indicative of organisms from one or more of genera of Marinobacter, Desulfovibrio, Methanohalophilus , and Halanaerobium;
comparing the signature of the second sample with the signature of the sample taken from the hydrocarbon seep;
using the compared signature to determine the temperature of the hydrocarbon reservoir.

9. The method of claim 7 , 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.

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

11. The method of claim 1 , wherein the salinity of the reservoir is identified as being in the range of from 5 to 25 wt %.

12. The method of claim 1 , wherein the salinity of the reservoir is identified as being in the range of from 10 to 25 wt %.

13. The method of claim 1 , wherein the salinity of the reservoir is identified as being in the range of 15 to 25 wt %.

14. The method of claim 1 , further comprising using the determined salinity to identify the presence of one or more salt bodies in the seismic data.

Assignees

• Exxonmobil Upstream Res Co
• Exxonmobil Upstream Res Comapny

Inventors

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

Classifications

• G01N33/24

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

• E21B49/08 Primary

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

• E21B43/0122

  Collecting oil or the like from a submerged leakage (cleaning or keeping clear the surface of open water from oil or the like E02B15/04) · CPC title

• C12Q1/689

  for bacteria · CPC title

• C12Q2600/158

  Expression markers · CPC title