Assessing reservoir connectivity in hydrocarbon reservoirs

Patent metadata

Field	Value
Publication number	US-9416656-B2
Application number	US-201314406516-A
Country	US
Kind code	B2
Filing date	Mar 7, 2013
Priority date	Jun 8, 2012
Publication date	Aug 16, 2016
Grant date	Aug 16, 2016

Abstract

A method is disclosed for assessing connectivity between sections in a hydrocarbon reservoir. Samples of hydrocarbons are collected over different depths in at least one wellbore. Fluorescence intensity determines the actual heavy end concentrations of hydrocarbons for the corresponding different depths. Estimated heavy end concentrations of hydrocarbons for corresponding different depths are determined and the actual heavy end concentrations of hydrocarbons are compared with the estimated heavy end concentrations to assess connectivity between sections of the hydrocarbon reservoir.

First claim

That which is claimed is:

1. A method of assessing connectivity between sections in a hydrocarbon reservoir, comprising:
collecting a plurality of hydrocarbon samples over corresponding different depths within the hydrocarbon reservoir;
using fluorescence intensity to determine a plurality of actual heavy end concentrations of hydrocarbons for the corresponding different depths based upon the plurality of hydrocarbon samples;
determining a plurality of estimated heavy end concentrations of hydrocarbons for the corresponding different depths; and
comparing the plurality of actual heavy end concentrations of hydrocarbons with the plurality of estimated heavy end concentrations of hydrocarbons to assess connectivity between sections of the hydrocarbon reservoir.

2. The method according to claim 1 wherein the hydrocarbon comprises a gas condensate.

3. The method according to claim 1 wherein the hydrocarbon comprises a wet gas.

4. The method according to claim 1 wherein the hydrocarbon comprises a volatile oil.

5. The method according to claim 1 wherein the hydrocarbon comprises a fluid containing <1 wt % asphaltene.

6. The method according to claim 1 wherein the hydrocarbon comprises fluid with <0.1 optical density(OD) absorption in the visible or near-infrared spectral regions.

7. The method according to claim 1 wherein the hydrocarbon comprises fluid having heavy ends exist as isolated molecules.

8. The method according to claim 1 wherein the hydrocarbon comprises fluid having fluorescence that is proportional to the heavy end content.

9. The method according to claim 1 wherein the plurality of estimated heavy end concentrations of hydrocarbons have a gradient over the depth of a wellbore indicative of connectivity between sections of the hydrocarbon reservoir.

10. The method according to claim 1 wherein determining the plurality of estimated heavy end concentrations comprises using a Flory-Huggins-Zuo Equation of State (FHZ EOS) model.

11. A system of assessing connectivity between sections in a hydrocarbon reservoir traversed by at least one wellbore, the system comprising:
at least one tool to
collect a plurality of hydrocarbon samples over corresponding different depths within the at least one wellbore, and
use fluorescence intensity to determine a plurality of actual heavy end concentrations of hydrocarbons for the corresponding different depths based upon the plurality of hydrocarbon samples; and

a processor cooperating with said at least one tool to
determine a plurality of estimated heavy end concentrations of hydrocarbons for the corresponding different depths, and
compare the plurality of actual heavy end concentrations of hydrocarbons with the plurality of estimated heavy end concentrations of hydrocarbons to assess connectivity between sections of the hydrocarbon reservoir.

12. The system according to claim 11 wherein the plurality of estimated heavy end concentrations have a gradient over the depth of the wellbore indicative of connectivity between sections of the hydrocarbon reservoir.

13. The system according to claim 11 wherein said processor determines the plurality of estimated heavy end concentrations using a Flory-Huggins-Zuo Equation of State (FHZ EOS) model.

14. The system according to claim 11 wherein the heavy end concentrations are based upon concentrations of aromatics and resins.

15. A non-transitory computer readable medium executable on a processor to perform steps to assess connectivity between sections in a hydrocarbon reservoir traversed by at least one wellbore from which a plurality of hydrocarbon samples have been collected over corresponding different depths within the wellbore, and for which fluorescence intensity has been used to determine a plurality of actual heavy end concentrations of hydrocarbons for the corresponding different depths based upon the plurality of hydrocarbon samples, the steps comprising:
determining a plurality of estimated heavy end concentrations of hydrocarbons for the corresponding different depths; and
comparing the plurality of actual heavy end concentrations of hydrocarbons with the plurality of estimated heavy end concentrations of hydrocarbons to assess connectivity between sections of the hydrocarbon reservoir.

16. The non-transitory computer readable medium according to claim 15 wherein the plurality of estimated heavy end concentrations have a gradient over the depth of the wellbore indicative of connectivity between sections of the hydrocarbon reservoir.

17. The non-transitory computer readable medium according to claim 15 wherein determining the plurality of estimated heavy end concentrations comprises using a Flory-Huggins-Zuo Equation of State (FHZ EOS) model.

18. The non-transitory computer readable medium according to claim 15 wherein the heavy end concentrations are based upon concentrations of aromatics and resins.

Assignees

• Schlumberger Technology Corp

Inventors

• Pomerantz Andrew E
• Zuo Youxiang
• Mullins Oliver C

Classifications

• E21B47/00 Primary

  Survey of boreholes or wells (monitoring pressure or flow of drilling fluid E21B21/08) · CPC title

• E21B49/02

  by mechanically taking samples of the soil · CPC title

• G01N21/64

  Fluorescence; Phosphorescence · CPC title

• E21B49/082 Primary

  Wire-line fluid samplers (E21B49/083 takes precedence) · CPC title

• E21B47/10

  Locating fluid leaks, intrusions or movements · CPC title