Method and apparatus for finding horizons in 3D seismic data
First Claim
1. Apparatus for automatically picking horizons from a three dimensional volume of seismic data traces and creating an indicia volume representative of horizons in the earth'"'"'s crust, where a horizon is a bedding interface in the earth'"'"'s crust and is represented in said seismic data traces through said bedding interface by a common attribute of a seismic wavelet, and where said common attribute may vary in depth as a function of x-y coordinates of said seismic data traces, comprisingcomputer program means for converting each of said seismic data traces to an indicia trace defined by a sequence of a first indicium and a second indicium as a function of depth, where a first indicium at any depth of such indicia trace indicates that a horizon exists at such depth of said seismic data trace and a second indicium at any depth of such indicia trace indicates that a horizon does not exist at such depth of said seismic data trace, andmeans for storing each of said indicia traces in the memory of a computer as a three-dimensional indicia volume of indicia traces.
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Abstract
A method and apparatus of rapidly generating horizon maps from a three dimensional volume of seismic traces is disclosed. During batch processing of the digital data representing trace wavelets, "1"'"'"'s are "0"'"'"'s are determined for each seismic trace of the volume. A bit volume is produced of which a "1" at a depth of a trace indicates that a horizon exists at that depth and at other depths of "1"'"'"'s of adjacent traces which are within a predetermined depth. In a real time mode, an explorationist selects a seed point thereby identifying a "1" on a particular trace at a particular depth. An automatic scanning procedure finds all other "1"'"'"'s at depths of adjacent traces. Each found "1" of adjacent traces is redesignated a seed point and the process is continued until no more "1"'"'"'s can be found. A horizon map is created from the depths of each found "1". An alternative method and apparatus is disclosed by which such bit volume is replaced with a compressed trace volume where each bit of the bit volume is replaced with a numerical value corresponding to the precise depth location of the attribute extremum represented by the bit. Such depth values are stored consecutively to form compressed traces. Interpolation of wavelets to find maximum or minimum attributes of such wavelets identifies depths above or below a bit of the bit volume which allows the production of an interpolated compressed trace volume.
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Citations
28 Claims
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1. Apparatus for automatically picking horizons from a three dimensional volume of seismic data traces and creating an indicia volume representative of horizons in the earth'"'"'s crust, where a horizon is a bedding interface in the earth'"'"'s crust and is represented in said seismic data traces through said bedding interface by a common attribute of a seismic wavelet, and where said common attribute may vary in depth as a function of x-y coordinates of said seismic data traces, comprising
computer program means for converting each of said seismic data traces to an indicia trace defined by a sequence of a first indicium and a second indicium as a function of depth, where a first indicium at any depth of such indicia trace indicates that a horizon exists at such depth of said seismic data trace and a second indicium at any depth of such indicia trace indicates that a horizon does not exist at such depth of said seismic data trace, and means for storing each of said indicia traces in the memory of a computer as a three-dimensional indicia volume of indicia traces.
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11. In a method of automatically picking horizons from a three dimensional volume of seismic data traces, where a horizon is a bedding interface in the earth'"'"'s crust and is represented in said seismic data traces through said bedding interface by a common attribute of a seismic wavelet, a method of creating a compressed trace volume comprising the steps of,
identifying for each of said seismic data traces depths at which horizons exists, and storing for each such seismic data trace a sequence of numerical values representative of said depths at which said horizons exist to create compressed traces of a compressed trace volume, where a compressed trace is defined as a sequence of numbers representative of the depths of a seismic data trace at which horizons exist, and a compressed trace volume is defined as a three dimensional volume of compressed traces, where each compressed trace corresponds to one of said seismic data traces of said three dimensional volume of seismic traces.
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20. Apparatus for automatically picking horizons from a three dimensional volume of seismic data traces, where a horizon is a bedding interface in the earth'"'"'s crust and is represented in said seismic data traces through said bedding interface by a common attribute of a seismic wavelet, and for creating a compressed trace volume comprising,
computer program means for identifying for each of said seismic data traces depths at which horizons exists, and means for storing for each such seismic data trace a sequence of numerical values representative of said depths at which said horizons exist to create compressed traces of a compressed trace volume, where a compressed trace is defined as a sequence of numbers representative of the depths of a seismic data trace at which horizons exist, and a compressed trace volume is defined as a three dimensional volume of compressed traces, where each compressed trace corresponds to one of said seismic data traces of said three dimensional volume of seismic traces.
Specification