Method of characterizing texture heterogeneities of geological formations traversed by a borehole

• US 5,809,163 A
• Filed: 02/16/1995
• Issued: 09/15/1998
• Est. Priority Date: 02/26/1991
• Status: Expired due to Term

• Current Assignee: Schlumberger Technology Corporation (SLB)
• Original Assignee: Schlumberger Technology Corporation (SLB)
• Inventors: Rivest, Jean-Fran.cedilla.ois, Delhomme, Jean-Pierre
• Primary Examiner(s): Boudreau, Leo
• Assistant Examiner(s): KELLEY, CHRISTOPHER S
• Application Number:
  US08/390,268
• Time in Patent Office: 1,307 Days
• Field of Search: 382/109, 348/85, 364/422, 367/35, 367/69, 324/323, 324/366, 324/367, 324/355, 73/151, 73/152
• US Class Current: 382/109
• CPC Class Codes: E21B 47/002 by visual inspection
• CPC Class Codes: E21B 47/0025 generating an image of the borehole wall using down-hole measurements, e.g. acoustic or electric
• CPC Class Codes: E21B 49/00 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 Class Codes: G01N 27/041 of a solid body
• CPC Class Codes: G01V 3/38 Processing data, e.g. for analysis, for interpretation, for correction

Abstract

A method of characterizing texture heterogeneities in a geological formation traversed by a borehole. The method records an image of the borehole wall such as that provided by Schlumberger'"'"'s Formation Microscanner (FMS) apparatus, representative of variations in a physical parameter of the formation in the longitudinal direction of the borehole and around the periphery of the wall. Geological objects are extracted from the image corresponding to a determined morphological type of heterogeneity. The variation in at least one attribute defined for this type of heterogeneity in the longitudinal direction of the borehole is determined. The invention is particularly applicable to vug detection.

Claims

1. A method of characterizing texture heterogeneities of a structure in a geological formation traversed by a borehole, represented by an image of a circumferential segment of a borehole wall having variations in a physical parameter of the formation in the longitudinal direction of the borehole and around a periphery of a wall of the borehole, comprising the steps of:

a) obtaining signals representative of a two-dimensional reconstructed image of an in-situ section of an earth formation

b) automatically processing the signals to extract from the image, by means of mathematical morphological operators, a further reconstructed image in which geological objects correspond to a determined morphological type of heterogeneity, defined as an enclosed zone having high value for said parameter, wherein said objects are present in such a way that said objects are capable of being automatically extracted from the further image thus produced to indicate a discontinuity within said structure corresponding to said enclosed zone; and

c) determining the variation in the longitudinal direction of the borehole of at least one attribute defined for the morphological type of heterogeneity.

4. A method according to claim 1, in which geological objects extracted from the image are vugs.

18. A method according to claim 4, in which an attribute used is the proportion of the area of the image that is occupied by the vugs.

19. A method according to claim 4, in which an attribute used is the mean area of the vugs.

20. A method according to claim 19, in which an attribute used is the proportion of the area of the image that is occupied by the vugs.

21. A method according to claim 4, in which interconnection lines between vugs are also extracted from the image.

22. A method according to claim 18, in which interconnection lines between vugs are also extracted from the image.

23. A method according to claim 19, in which interconnection lines between vugs are also extracted from the image.

24. A method according to claim 21, in which the mean of the values of said parameter in the lines interconnecting the vugs is used as an attribute.

2. A method of characterizing texture heterogeneities of a structure in a geological formation traversed by a borehole, represented by an image of a circumferential segment of a borehole wall having variations in a physical parameter of the formation in the longitudinal direction of the borehole and around a periphery of a wall of the borehole, comprising the steps of:

1) automatically processing the image to extract from the image, by means of mathematical morphological operators, at least an image in which geological objects correspond to a determined morphological type of heterogeneity, defined as an enclosed zone having high value for said parameter wherein objects having a high value of said parameter or of a magnitude derived therefrom are marked, objects having a low value of said parameter or of a magnitude derived therefrom are marked, and the outlines of said objects are determined as a function of values for the gradient of said parameter in such a way that said objects are capable of being automatically extracted from the image thus produced to indicate a discontinuity within said structure corresponding to said enclosed zone; and

2) determining the variation in the longitudinal direction of the borehole of at least one attribute defined for the morphological type of heterogeneity.

3. A method according to claim 2, in which geological objects extracted from the image are vugs.

5. A method according to claim 3, in which an attribute used is the proportion of the area of the image that is occupied by the vugs.

6. A method according to claim 3, in which an attribute used is the mean area of the vugs.

7. A method according to claim 6, in which an attribute used is the proportion of the area of the image that is occupied by the vugs.

8. A method according to claim 3, in which interconnection lines between vugs are also extracted from the image.

9. A method according to claim 5, in which interconnection lines between vugs are also extracted from the image.

10. A method according to claim 6, in which interconnection lines between vugs are also extracted from the image.

11. A method according to claim 8, in which the mean of the values of said parameter in the lines interconnecting the vugs is used as an attribute.

12. A method of characterizing texture heterogeneities of a structure in a geological formation traversed by a borehole, represented by an image of a circumferential segment of a borehole wall having variations in a physical parameter of the formation in the longitudinal direction of the borehole and around a periphery of a wall of the borehole, comprising the steps of:

1) automatically processing the image to extract from the image, by means of mathematical morphological operators, at least an image in which;

a) geological objects corresponding to a determined morphological type of heterogeneity are defined as an enclosed zone having high value for said parameter,

b) geological objects having a high value of said parameter are indicated as vugs;

c) , geological objects having a low value of said parameter are indicated as other than vugs; and

d) outlines of said objects are determined as a function of values for the gradient of said parameter;

wherein said vugs are present in such a way that said vugs are capable of being automatically extracted from the image thus produced to indicate a discontinuity within said structure corresponding to said enclosed zone; and

2) determining the variation of one attribute of the vugs in the longitudinal direction of the borehole, said attribute relating to the area of the vugs.

13. The method of claim 12, said attribute relating to a proportion of an area of said image occupied by said vugs.

14. The method of claim 12, said attribute relating to the mean area of said vugs.

15. A method of characterizing a formation, the steps comprising:

1) producing an image of a circumferential segment of a borehole wall having variations in a physical parameter of the formation in a longitudinal direction of the borehole and around a periphery of a wall of the borehole, wherein the image indicates the structure of the formation;

2) using mathematical morphological operators to automatically process the image indicating the structure and automatically extract discontinuities in the structure;

3) correlating high values of the parameter with vugs and correlating low values of the parameter with objects other than vugs;

4) determining outlines of the vugs and objects other than vugs as a function of values of a gradient of the parameter,

5) determining a variation of an attribute of the vugs in the longitudinal direction of the borehole;

6) indicating discontinuities in the structure as the vugs in the formation based on the variation of the attribute of the vugs.

16. The method of claim 15, the attribute comprising a proportional area of the image which is occupied by the vugs.

17. The method of claim 15, the attribute comprising the mean area of the vugs.