Claims
- 1. In the art of well logging, a process for converting well logging signals which comprise records of the amplitude of subsurface characteristics versus depth in a borehole into a map of the dips of one or more subsurface earth formation features comprising the machine-implemented steps of:
- a. utilizing well logging signals derived from respective passes of investigating devices along the wall of a borehole through a subsurface formation to produce signals determined by the likely displacements between the respective reflections of respective subsurface features on said well logging signals in at least two different depth spans in the borehole;
- b. producing a map record which conforms to a plane transverse to the borehole axis and contains a number of map line representations the position of each of which on the map record conforms to a range of dips consistent with a respect one of said displacement signals;
- c. wherein said displacement signals relate to respective borehole depths within a selected depth interval of the borehole which is small as compared to the depth of the entire borehole; and
- d. wherein a predominant locus of intersections of such line representations on the map record determines a likely dip of a subsurface feature which is in the borehole depth interval to which said depth displacement signals correspond.
- 2. The process of claim 1 in which the step of producing the map record includes varying the line representations in accordance with the integrity of the respective displacement signals consistent therewith to enhance the determination of a likely locus, and thereby of a likely dip, of higher integrity as compared to the determination of a likely dip of lower integrity.
- 3. The process of claim 2 in which the step of varying the line representations comprises varying the intensity thereof to enhance the intensity of a predominant locus and thereby the determination of a likely dip.
- 4. The process of claim 3 in which: said line representation comprises a line in a plane normal to the axis of the borehole as determined from the position of a borehole tool carrying said investigating devices; the position of a line in said plane is determined by the magnitude and orientation of the respective displacement; and the intensity of a line is varied in accordance with the quality of the respective displacement represented thereby, the intensity increasing with increasing quality.
- 5. The process of claim 4 in which the step of varying the intensity of a line comprises varying the intensity in accordance with the accuracy of the respective displacement represented thereby.
- 6. The process of claim 5 in which the intensity is higher for more accurate displacements than for less accurate displacements of the same quality.
- 7. The process of claim 3 in which: said line representation comprises a line in a plane normal to the axis of the borehole as determined from the position of a borehole tool carrying said investigating devices; the position of the line in the plane is determined from the magnitude and orientation of the displacement represented thereby; and the intensity of the line is varied in accordance with the accuracy of the displacement represented thereby, the intensity increasing with increasing accuracy of the respective displacement.
- 8. The process of claim 7 in which the step of varying the intensity of a line comprises varying the intensity in accordance with the quality of the displacement represented thereby.
- 9. The process of claim 8 in which the intensity is higher for displacements of better quality than for displacements of lower quality which have comparable displacement accuracy.
- 10. The process of claim 1 in which the step of producing a map record comprises producing a map record of said line representations which is on a record medium and is visible by the unaided eye, and which contains at least one observable predominant locus.
- 11. In the art of well logging, a process for converting geophysical signals which comprise records of subsurface geophysical properties versus depth in a borehole into a map record of the dip of one or more subsurface formation features comprising the machine-implemented steps of:
- a. producing at least two signals for respective displacements obtained for respective similar features in respective different borehole depth intervals of at least one pair of geophysical signals derived from a respective pair of signal sources while at known positions in a borehole through a subsurface formation;
- b. producing a map record which conforms to a plane normal to the borehole axis and contains a respective line representation for each of said displacement signals, each line representation conforming to a range of possible subsurface formation dips corresponding to the respective displacement signal, said line representations being oriented on the map record according to the respective positions of the pair of signal sources corresponding to the respective displacements; and
- c. determining the position of coincidence of said line representations on said map record to determine thereby the corresponding dip of a subsurface formation feature reflected on said geophysical signals and producing a tangible record of the last recited dip of a subsurface feature.
- 12. The process of claim 11 in which the step of producing a map record includes varying the weight of a line representation in accordance with the integrity of its respective displacement signal to increase the weight contributed by the line representation to the determination of the position of coincidence and therefore to enhance the integrity of the determination of the corresponding dip of a subsurface formation feature.
- 13. The process of claim 12 in which the weight of a line representation is higher for a better quality displacement signal as compared to the weight for a poorer quality displacement signal.
- 14. The process of claim 12 in which the weight of a line representation is higher for a more accurate displacement signal as compared to the weight for a less accurate displacement signal.
- 15. The process of claim 12 in which the weight of a line representation is higher for a higher ratio of quality to accuracy of the respective displacement signal as compared to a lower ratio.
- 16. The process of claim 12 in which the weight of a line representation is varied by varying the width thereof, a wider line representation having less weight as compared to the weight of a narrower line representation which corresponds to a displacement signal of the same quality.
- 17. A method of machine-converting displacement signals obtained from pairs of geophysical signals derived from signal sources located at respective positions in a borehole penetrating subsurface formations into signals indicative of the dip of one or more subsurface formations reflected on said signals, comprising:
- a. producing, for each of at least two different intervals in the borehole, a displacement signal obtained from a pair of geophysical signals derived from signal sources at known positions in the borehole, each displacement signal being determined by the displacement between a reflection on one of the geophysical signals of a pair and a similar reflection on the other;
- b. representing a range of possible dips corresponding to each of said at least two displacement signals, each representation of a range of possible dips corresponding to a respective displacement signal reflecting the known positions of the pair of signal sources producing the geophysical signals from which the respective displacement signal was obtained; and
- c. determining the position of coincidence of said possible dip representations and the corresponding likely dip of a formation reflected on said geophysical signals and producing and storing dip signals indicative of the last recited dip of a subsurface formation.
- 18. A method as in claim 17 in which the step of representing possible dips includes varying the representation in accordance with the integrity of the represented displacements in order to enhance the determination of the position of coincidence for representations of higher integrity as compared to representations of lower integrity.
- 19. A method as in claim 18 including representing more than one possible displacement in a given depth interval in the borehole and varying the representation of each such displacement in the interval in accordance with its integrity while also normalizing the variation of the representations for the number of such displacements in the interval.
- 20. A method as in claim 17 including producing a visible map record of said possible dip representations in which the representations are shown as lines at positions indicative of the possible dips thereof and a predominant intersection of said lines is indicative of said likely dip of a subsurface formation.
- 21. A method of machine-converting displacement signals obtained from pairs of geophysical signals derived from signal sources at respective positions in a borehole penetrating subsurface formations into dip signals indicative of the relative position of subsurface formation features reflected on said geophysical signals, comprising:
- a. using a multiplicity of displacement signals obtained from at least one pair of geophysical signals derived from signal sources spaced around a borehole at respective positions, each displacement signal being related to the positions of a pair of the signal sources in the borehole at the time each receives a respective one of two similar reflections of a subsurface feature;
- b. representing each of said displacement signals as a line on a record which conforms to a plane transverse to the axis of the borehole, each line corresponding to a range of possible dips for a respective displacement signal and reflecting the respective positions of the signal sources corresponding to the last recited displacement signal;
- c. determining the position of highest coincidence of said lines corresponding to ranges of possible dips; and
- d. determining from said record the dip corresponding to said determined position of highest coincidence and producing dip signals indicative of the corresponding dip of the subsurface formation features reflected on said geophysical signals.
- 22. The method of claim 21 in which each of said lines on the record passes by the borehole axis intersection with said plane at a distance which increases with increasing magnitude of the displacement representing by the respective displacement signal.
- 23. The method of claim 22 in which the step of representing each of said displacement signals as a line corresponding to a range of possible dips includes varying the weight of the line in accordance with the quality of the represented displacement to increase the contribution of a higher quality representation relative to a lower quality representation to the determination of the position of coincidence between said representations and therefore the determination of the corresponding dip of the subsurface formation feature.
- 24. The method of claim 21 including producing a visible map record of said lines.
- 25. A system for converting well logging signals comprising records of the amplitude of subsurface characteristics versus depth in a borehole into dip signals comprising a record of the dip of one or more subsurface features comprising:
- a. means for utilizing well logging signals derived from respective passes of investigating devices along the wall of a borehole through a subsurface formation to produce displacement signals determined by the likely displacement between the respective reflections of respective subsurface features on said well logging signals in at least two different depth spans in the borehole; and
- b. means for producing and storing signals defining a map record which conforms to a plane transverse to the borehole axis and comprises line signals defining a number of map line representations the position of each of which on the map record conforms to a range of dips consistent with a respective one of said displacement signals, wherein said displacement signals relate to respective borehole depths within a selected depth interval of the borehole which is small as compared to the depth of the entire borehole, and wherein a predominant locus of intersections of such line representations on the map record determines a likely dip of a subsurface feature which is in the borehole depth interval to which said displacement signals relate.
- 26. A system as in claim 25 in which the producing means include means for producing a visible map record showing said map line representations.
Priority Claims (1)
Number |
Date |
Country |
Kind |
74 03003 |
Jan 1974 |
FRX |
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Parent Case Info
This is a continuation, of application Ser. No. 544,421 filed Jan. 27, 1975 and now abandoned.
US Referenced Citations (5)
Continuations (1)
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Number |
Date |
Country |
Parent |
544421 |
Jan 1975 |
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