Determining the robustness of discrete fracture network permeability estimates

Patent metadata

Field	Value
Publication number	US-10329904-B2
Application number	US-201615074621-A
Country	US
Kind code	B2
Filing date	Mar 18, 2016
Priority date	Mar 18, 2016
Publication date	Jun 25, 2019
Grant date	Jun 25, 2019

Abstract

Examples of techniques for determining robustness of a discrete fracture network (DFN) permeability estimate are disclosed. In one example implementation according to aspects of the present disclosure, a method may include: receiving a DFN of an earth formation of interest, the DFN comprising a plurality of connected fractures; determining a directional equivalent permeability of the plurality of connected fractures of the DFN using a numerical upscaling method; and determining the robustness of the directional equivalent permeability.

First claim

What is claimed is:

1. A method for determining robustness of a discrete fracture network (DFN) permeability estimate, the method comprising:
collecting a core sample of an earth formation of interest;
generating the DFN of the earth formation of interest from the core sample;
receiving a DFN of the earth formation of interest, the DFN comprising a plurality of connected fractures;
determining, by a processing device, a directional equivalent permeability of the plurality of connected fractures of the DFN using a numerical upscaling method by capturing a series of slices taken incrementally about a center point of the DFN;
determining, by the processing device, the robustness of the directional equivalent permeability; and
performing an action relating to the earth formation of interest using the directional equivalent permeability, the action comprising aligning a tool in a direction determined by the directional equivalent permeability.

2. The method of claim 1 , wherein the directional equivalent permeability is a first directional equivalent permeability, and wherein determining the robustness of the first directional equivalent permeability comprises comparing the directional equivalent permeability to a second directional equivalent permeability.

3. The method of claim 1 , wherein determining the robustness of the directional equivalent permeability comprises computing a robustness measure based on a change in the directional equivalent permeability.

4. The method of claim 3 , wherein the change in the directional equivalent permeability includes at least one selected from the group consisting of: a number of steps between neighboring angles, a size of steps between neighboring angles, a slope of an equivalent permeability with changing direction, a variance measure computed with changes in an equivalent permeability with direction.

5. The method of claim 3 , wherein the robustness measure of the directional equivalent permeability is compared with the robustness measures from another DFN.

6. The method of claim 1 , wherein the action comprises:
performing in-fill drilling in a direction determined by the directional equivalent permeability.

7. The method of claim 1 , wherein the action comprises:
performing a reservoir stimulation in a direction determined by the directional equivalent permeability.

8. The method of claim 1 , wherein the numerical upscaling method comprises performing a perfect fit analysis.

9. A method for determining robustness of a discrete fracture network (DFN) permeability estimate, the method comprising:
receiving a DFN of an earth formation of interest, the DFN comprising a plurality of connected fractures;
determining, by a processing device, a directional equivalent permeability of the plurality of connected fractures of the DFN using a numerical upscaling method;
determining, by the processing device, the robustness of the directional equivalent permeability; and
performing an action relating to the earth formation of interest using the directional equivalent permeability, the action comprising aligning a tool in a direction determined by the directional equivalent permeability,
wherein the directional equivalent permeability is a first directional equivalent permeability, and wherein determining the robustness of the first directional equivalent permeability comprises comparing the directional equivalent permeability to a second directional equivalent permeability, and
wherein comparing further comprises comparing smoothness between the first directional equivalent permeability and the second directional equivalent permeability.

10. The method of claim 9 , wherein comparing further comprises calculating a difference between the first directional equivalent permeability to the second directional equivalent permeability, where the first directional equivalent permeability is scaled by a constant factor.

11. The method of claim 10 , wherein the difference represents a difference in a smoothness of a graphical representation of the first directional equivalent permeability and the second directional equivalent permeability.

12. A system for determining robustness of a discrete fracture network (DFN) permeability estimate, the system comprising:
a memory having computer readable instructions; and
a processing device for executing the computer readable instructions, the computer readable instructions comprising:
receiving a DFN of an earth formation of interest, the DFN comprising a plurality of connected fractures;
determining a first directional equivalent permeability of the plurality of connected fractures of the DFN using a numerical upscaling method by capturing a first series of slices taken incrementally about a center point of the DFN;
determining a second directional equivalent permeability of the plurality of connected fractures of the DFN using Oda's method by capturing a second series of slices taken incrementally about a center point of the DFN, wherein the DFN is cropped to fit the second series of slices;
determining a robustness of the first directional equivalent permeability by comparing the first directional equivalent permeability to the second directional equivalent permeability; and
performing an action relating to the earth formation of interest using the first directional equivalent permeability, wherein the performing the action comprises aligning a drill in a direction determined by the first directional equivalent permeability.

13. The system of claim 12 , wherein comparing the first directional equivalent permeability to the second directional equivalent permeability comprises calculating a difference between the first directional equivalent permeability to the second directional equivalent permeability.

14. The system of claim 13 , wherein the difference represents a difference in a smoothness of a graphical representation of the first directional equivalent permeability and the second directional equivalent permeability.

Assignees

• Hoeink Tobias
• Baker Hughes A Ge Co Llc

Inventors

• Hoeink Tobias

Classifications

• G06G7/48

  Analogue computers for specific processes, systems or devices, e.g. simulators · CPC title

• E21B43/24

  using heat, e.g. steam injection · CPC title

• E21B49/00 Primary

  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

• E21B7/04

  Directional drilling · CPC title

• E21B37/00

  Methods or apparatus for cleaning boreholes or wells (E21B21/00 takes precedence) · CPC title