AUTOMATIC METHOD FOR THREE-DIMENSIONAL STRUCTURAL INTERPRETATION OF BOREHOLE IMAGES ACQUIRED IN HIGH-ANGLE AND HORIZONTAL WELLS
First Claim
1. A method comprising:
- accepting as input to a processor an azimuthally substantially continuous wellbore image obtained using a well logging tool moved along a wellbore penetrating a subsurface formation;
in the processor, extracting contours from the substantially azimuthally continuous image;
in the processor, grouping the extracted contours into clusters corresponding to a single transition zone; and
in the processor, mapping the clustered contours having a measured depth extent that is greater than a length-scale over which a dip of the subsurface formation varies to a three-dimensional space corresponding to a coordinate system associated with the well; and
in the processor, calculating a dip and azimuth of a layer boundary of the subsurface formation from the mapped clustered contours and at least one of storing and displaying the calculated dip and azimuth.
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Abstract
A method for automatic interpretation of bulls-eye and sinusoidal features observed in LWD images is disclosed. In some embodiments, the method includes an automatic workflow for extracting smooth contours from images that demarcate boundaries of structural features, followed by projection of the contours to three-dimensional (3D) point clouds in the well coordinate system for structural interpretation. The method may characterize both sinusoidal features and bulls-eye features, taking into account variations of formation dip/azimuth, or well inclination/azimuth, on the topology of a structural feature. The disclosed method may be sufficiently fast for use in real-time analysis and interpretation, or to provide constraints for physics-based data inversion processing.
11 Citations
20 Claims
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1. A method comprising:
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accepting as input to a processor an azimuthally substantially continuous wellbore image obtained using a well logging tool moved along a wellbore penetrating a subsurface formation; in the processor, extracting contours from the substantially azimuthally continuous image; in the processor, grouping the extracted contours into clusters corresponding to a single transition zone; and in the processor, mapping the clustered contours having a measured depth extent that is greater than a length-scale over which a dip of the subsurface formation varies to a three-dimensional space corresponding to a coordinate system associated with the well; and in the processor, calculating a dip and azimuth of a layer boundary of the subsurface formation from the mapped clustered contours and at least one of storing and displaying the calculated dip and azimuth. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method for determining dip and azimuth of a subsurface formation, comprising:
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moving a well logging tool along an interior of a wellbore penetrating the subsurface formation to generate a substantially azimuthally continuous image from measurements made by the well logging tool; in a processor, extracting contours from the substantially azimuthally continuous image; in the processor, grouping the extracted contours into clusters corresponding to a single transition zone; in the processor, mapping the clustered contours having a measured depth extent that is greater than a length-scale over which a dip of the subsurface formation varies to a three-dimensional space corresponding to a coordinate system associated with the well; and in the processor, calculating a dip and azimuth of a layer boundary of the subsurface formation from the mapped clustered contours and at least one of storing and displaying the calculated dip and azimuth. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A system for determining dip and azimuth of a subsurface formation, comprising:
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a processor programmed to accept as input thereto an azimuthally substantially continuous wellbore image obtained using a well logging tool moved along a wellbore penetrating a subsurface formation; the processor programmed to extract contours from the substantially azimuthally continuous image; the processor programmed to group the extracted contours into clusters corresponding to a single transition zone; the processor programmed to map the clustered contours having a measured depth extent that is greater than a length-scale over which a dip of the subsurface formation varies to a three-dimensional space corresponding to a coordinate system associated with the well; and the processor programmed to calculate a dip and azimuth of a layer boundary of the subsurface formation from the mapped clustered contours and at least one of storing and displaying the calculated dip and azimuth.
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Specification