Determination of depositional environments

Patent metadata

Field	Value
Publication number	US-11549894-B2
Application number	US-202016840892-A
Country	US
Kind code	B2
Filing date	Apr 6, 2020
Priority date	Apr 6, 2020
Publication date	Jan 10, 2023
Grant date	Jan 10, 2023

Abstract

Methods are provided for determining a depositional environment of a sample of a subterranean environment. An example method includes measuring intensities for a crystallographic plane (CP) 100 peak and a CP 101 peak for quartz in a diffractogram, calculating a ratio of the intensities of the CP 100 peak to the CP 101 peak, and identifying a depositional environment for the sample from the ratio.

First claim

What is claimed is:

1. A method for determining a depositional environment of a sample of a subterranean environment, comprising:
micronizing the sample;
loading the sample in an x-ray diffraction sample holder;
measuring intensities for a crystallographic plane (CP) 100 peak for quartz and a CP 101 peak for quartz in a diffractogram;
calculating a ratio of the intensities of the CP 100 peak for quartz to the CP 101 peak for quartz; and
identifying a depositional environment for the sample from the ratio, wherein a correlation between the depositional environment and the ratio is determined by petrographic analysis.

2. The method of claim 1 , further comprising obtaining the sample from a core sample.

3. The method of claim 1 , further comprising obtaining the sample from cuttings from a drilling process.

4. The method of claim 1 , further comprising comparing peak intensities for other crystallographic planes to measure effects of sample preparation.

5. The method of claim 1 , further comprising comparing peak intensities for CP 112 peaks for quartz for samples from different depositional environments to measure effects of sample preparation.

6. The method of claim 1 , further comprising comparing peak intensities for CP 211 peaks for quartz for samples from different depositional environments to measure effects of sample preparation.

7. The method of claim 1 , further comprising correlating intensity ratios to depositional environment by:
determining the depositional environment for each of a plurality of samples;
measuring the intensity for the CP 100 peak for quartz and the CP 101 peak for quartz for each of the plurality of samples;
calculate the ratio of the intensity of the CP 100 peak for quartz to the CP 101 peak for quartz for each of the plurality of samples; and
correlate the intensity ratio for each of the plurality of samples to the depositional environment.

8. The method of claim 7 , further comprising determining the depositional environment for each of the plurality of samples through a petrographic analysis.

9. The method of claim 1 , further comprising screening a plurality of samples obtained from cuttings generated during a well drilling for depositional environment.

10. The method of claim 1 , further comprising identifying a reservoir layer based, at least in part, on the depositional environment of the sample.

11. The method of claim 1 , further comprising locating a reservoir based, at least in part, on the depositional environment of the sample.

12. The method of claim 1 , further comprising drilling a wellbore to a reservoir based, at least in part, on the depositional environment of the sample.

13. The method of claim 1 , further comprising performing a seismic analyses of a potential location for a reservoir.

14. The method of claim 13 , further comprising using data from the seismic analyses to locate a site for drilling an exploratory well to collect core samples.

15. A method for determining a placement of a well in a reservoir, comprising:
obtaining a sample of rock from a facies in a wellbore;
grinding the sample to form a powder;
mounting the powder in a sample holder and inserting the sample holder in an x-ray diffraction instrument;
determining an intensity of the peak for a crystallographic plane (CP) 100 of quartz in the sample;
determining the intensity of the peak for a CP 101 of quartz in the sample;
calculating a ratio of the intensities for the CP 100 peak for quartz and the CP 101 peak for quartz;
comparing the ratio to a correlation between ratios and depositional environments;
identifying the depositional environment for the sample; and
determining the placement of the wellbore in the reservoir based, at least in part, on the depositional environment.

16. The method of claim 15 , further comprising drilling an exploratory well to obtain core samples of rock in a subterranean environment.

17. The method of claim 16 , further comprising obtaining the sample of rock from the core sample.

18. The method of claim 15 , further comprising obtaining the sample of rock from cuttings from drilling a wellbore.

19. The method of claim 15 , further comprising correlating intensity ratios to depositional environment by:
determining the depositional environment for each of a plurality of samples;
determining the intensity for the CP 100 peak for quartz and the CP 101 peak for quartz for each of the plurality of samples;
calculating the ratio of the intensity of the CP 100 peak for quartz to the CP 101 peak for quartz for each of the plurality of samples; and
correlating the intensity ratio for each of the plurality of samples to the depositional environment.

20. The method of claim 15 , further comprising:
collecting seismic data on a potential reservoir site; and
determining the placement of the wellbore in the reservoir based, at least in part, on the seismic data.

Assignees

• Saudi Arabian Oil Co

Inventors

• Soua Mohamed
• Jacobi David
• Estevez Gonzalez Jose Antonio

Classifications

• E21B41/00

  Equipment or details not covered by groups E21B15/00 - E21B40/00 · CPC title

• E21B49/00

  Testing the nature of borehole walls; Formation testing; Methods or apparatus for obtaining samples of soil or well fluids, specially adapted to earth drilling or wells · CPC title

• G01N23/207

  Diffractometry using detectors, e.g. using a probe in a central position and one or more displaceable detectors in circumferential positions · CPC title

• G01N23/2055 Primary

  Analysing diffraction patterns · CPC title

• G01V1/40

  specially adapted for well-logging · CPC title