Formation dip and azimuth processing technique
First Claim
1. A method of automatically producing with a machine three-dimensional representations of formation features from measurements indicative of dip and azimuth in a borehole beneath the earth'"'"'s surface, comprising:
- (a) computing apparent dip representations in a given azimuth from dip and azimuth measurements of formation features at various depths;
(b) computing apparent dip representations in a different given azimuth from said dip and azimuth measurements at said depths; and
(c) producing as a function of said depths a three-dimensional representation of the apparent dip representations computed in both of the given azimuths.
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Accused Products
Abstract
Illustrative embodiments of the present invention include methods and apparatus for processing measurements indicative of the dip and azimuth of formation features at various depths in a borehole to produce three-dimensional representations of the formation features. These three-dimensional representations may be in the form of two-dimensional presentations of apparent dip traces for various depths in one or more planes. The apparent dips may be varied with distance from the borehole in accordance with information derived from dips above and below a selected dip. The three-dimensional representations may also take the form of a contour map of a formation surface around the borehold which represents a three-dimensional structural model derived from dips above and below the contoured formation surface.
Dip and azimuth variations over a given interval are used to define a family of surfaces in a three-dimensional reference system. Each dip represents a possible tangent plane to one of the surfaces at its intersection with the borehole. Dips are statistically analyzed to define a structural model, such as intersecting or faulted planes or cylindrical folds. Once a model is defined, the position of any surface in the model with direction and distance away from the borehole may be found and represented as variations in apparent dip in a given azimuth or as variations in dip or contour lines.
A statistical analysis of combined dip and azimuth variations determines a dominant mode for a dip distribution which corresponds to the structural dip for an automatically determined interval, even though the interval may also contain many dips corresponding to stratigraphic or depositional features.
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Citations
46 Claims
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1. A method of automatically producing with a machine three-dimensional representations of formation features from measurements indicative of dip and azimuth in a borehole beneath the earth'"'"'s surface, comprising:
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(a) computing apparent dip representations in a given azimuth from dip and azimuth measurements of formation features at various depths; (b) computing apparent dip representations in a different given azimuth from said dip and azimuth measurements at said depths; and (c) producing as a function of said depths a three-dimensional representation of the apparent dip representations computed in both of the given azimuths. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method of automatically producing with a machine three-dimensional representations of formation features from measurements indicative of dip and azimuth in a borehole beneath the earth'"'"'s surface, comprising:
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(a) providing a structural model representing changes in dip and azimuth values; (b) selecting a dip and azimuth measurement of a formation feature at the borehole; (c) computing for the selected measurement the apparent dip representation with distance from the borehole in a given azimuth in accordance with the structural model; and (d) producing a three-dimensional representation of the apparent dip representation in the form of a trace corresponding to the intersection of the formation feature with a plane aligned in the direction of the given azimuth. - View Dependent Claims (13, 14)
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15. A method of automatically producing with a machine three-dimensional representations of formation features from measurements indicative of dip and azimuth in a borehole beneath the earth'"'"'s surface, comprising:
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(a) providing a structural model representing changes in dip and azimuth values; (b) selecting a dip and azimuth measurement of a formation feature at the borehole; (c) computing for the selected measurement the apparent dip representations with distance from the borehole in two given azimuths in accordance with the structural model; and (d) producing a three-dimensional representation of the computed dip representations with distance from the borehole in the given azimuths. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30)
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31. A method of automatically producing with a machine three-dimensional representations of formation features from measurements indicative of dip and azimuth in a borehole beneath the earth'"'"'s surface, comprising:
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(a) providing a structural model representing changes in dip and azimuth values; (b) selecting as a surface in the structural model a dip and azimuth measurement of a formation feature at the borehole; (c) computing the position of a characteristic of the formation feature surface in accordance with the structural model; and (d) producing a three-dimensional representation of the characteristic of the surface in the form of a trace corresponding to a constant value of the characteristic at the computed position. - View Dependent Claims (32, 33, 34)
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35. A method of automatically producing with a machine three-dimensional representations of formation features from measurements indicative of dip and azimuth in a borehole beneath the earth'"'"'s surface, comprising:
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(a) providing representative dip and azimuth values and the corresponding locations of borehole intersections of a number of formation features; (b) computing three-dimensional components representative of the dip and azimuth values; (c) combining said components to determine the degree and direction of any common components; (d) selecting equations for models composed of a family of surfaces most characteristic of the common components; and (e) fitting the selected equations to the components to provide a structural model for the family of surfaces;
which represent changes in dip and azimuth;and further including the steps of selecting as a surface in the structural model a dip and azimuth measurement of a formation feature at the borehole;
computing the position of a characteristic of the formation feature surface in accordance with the structural model; and
producing a three-dimensional representation of the characteristic of the surface in the form of a trace corresponding to a constant value of the characteristic at the computed position. - View Dependent Claims (36, 37)
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39. A method of automatically producing with a machine three-dimensional representations of formation features for measurements indicative of dip and azimuth in a borehole beneath the earth'"'"'s surface, comprising:
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(a) providing representative dip and azimuth values and the corresponding locations of borehole intersections of a number of formation features; (b) computing three-dimensional components representative of the dip and azimuth values; (c) combining said components to determine the degree and direction of any common components; (d) selecting equations for models composed of a family of surfaces most characteristic of the common components; and (e) fitting the selected equations to the components to provide a structural model for the family of surfaces;
which represent changes in dip and azimuth;and further including the steps of selecting a dip and azimuth measurement of a formation feature at the borehole;
computing the apparent dip representation with distance from the borehole in a given azimuth in accordance with the structural model; and
producing a three-dimensional representation of an apparent dip representation in the form of a trace corresponding to the intersection of the formation feature with a plane aligned in the direction of the given azimuth. - View Dependent Claims (40, 41)
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42. A method of automatically producing with a machine three-dimensional representations of formation features from measurements indicative of dip and azimuth in a borehole beneath the earth'"'"'s surface, comprising:
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(a) providing representative dip and azimuth values and the corresponding locations of borehole intersections of a number of formation features; (b) computing three-dimensional components representative of the dip and azimuth values; (c) combining said components to determine the degree and direction of any common components; (d) selecting equations for models composed of a family of surfaces most characteristic of the common components; and (e) fitting the selected equations to the components to provide a structural model for the family of surfaces;
which represent changes in dip and azimuth;and further including the steps of selecting a dip and azimuth measurement of a formation feature at the borehole;
computing the apparent dip representations with distance from the borehole in two given azimuths in accordance with the structural model; and
producing a three-dimensional representation of the computed dip representations with distance from the borehole in the given azimuths. - View Dependent Claims (38, 43, 44)
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45. An apparatus for automatically producing three-dimensional representations of formation features from measurements indicative of dip and azimuth in a borehole beneath the earth'"'"'s surface comprising:
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(a) means for computing apparent dip representations in two different given azimuths from dip and azimuth measurements of formation features at various depths; and (b) means responsive to said computed representations for producing as a function of said depths a three-dimensional representation of the apparent dip representations in the form of traces corresponding to the intersections of the formation features with planes aligned in the directions of said given azimuths.
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46. An apparatus for automatically producing three-dimensional representations of formation features from measurements indicative of dip and azimuth in a borehole beneath the earth'"'"'s surface, comprising:
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(a) means for providing a structural model representing changes in dip and azimuth values; (b) means responsive to said model for selecting a dip and azimuth measurement of a formation feature at the borehole and computing for said measurement the apparent dip representation with distance from the borehole in a given azimuth in accordance with the structural model; and (c) means responsive to said computations for producing a three-dimensional representation of said apparent dip representation in the form of a trace corresponding to the intersection of the formation feature with a plane aligned in the direction of the given azimuth.
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Specification