Multi-crosswell profile 3D imaging and method
First Claim
1. In a method of characterizing a specific numerical value of a particular proper at any position within a subterranean region of ground encompassing at least one borehole from which seismic data relating to said property is at least in part generated, the improvement comprising the step of:
- representing the value of said particular property as determined by said seismic data across said region using at least one continuous analytic function.
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Accused Products
Abstract
Characterizing the value of a particular property, for example, seismic velocity, of a subsurface region of ground is described. In one aspect, the value of the particular property is represented using at least one continuous analytic function such as a Chebychev polynomial. The seismic data may include data derived from at least one crosswell dataset for the subsurface region of interest and may also include other data. In either instance, data may simultaneously be used from a first crosswell dataset in conjunction with one or more other crosswell datasets and/or with the other data. In another aspect, the value of the property is characterized in three dimensions throughout the region of interest using crosswell and/or other data. In still another aspect, crosswell datasets for highly deviated or horizontal boreholes are inherently useful. The method is performed, in part, by fitting a set of vertically spaced layer boundaries, represented by an analytic function such as a Chebychev polynomial, within and across the region encompassing the boreholes such that a series of layers is defined between the layer boundaries. Initial values of the particular property are then established between the layer boundaries and across the subterranean region using a series of continuous analytic functions. The continuous analytic functions are then adjusted to more closely match the value of the particular property across the subterranean region of ground to determine the value of the particular property for any selected point within the region.
284 Citations
92 Claims
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1. In a method of characterizing a specific numerical value of a particular proper at any position within a subterranean region of ground encompassing at least one borehole from which seismic data relating to said property is at least in part generated, the improvement comprising the step of:
representing the value of said particular property as determined by said seismic data across said region using at least one continuous analytic function. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. In a method of mapping a specific numerical value of a particular property at any position within a subterranean region of ground surrounding at least two boreholes where at least a first crosswell seismic data profile has been generated between a pair of two boreholes and wherein other data may also be available, the improvement comprising the step of:
simultaneously using certain portions of said first crosswell seismic data profile and said other data to establish the value of said property throughout said subterranean region. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 92)
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32. A method of establishing a specific numerical value of a particular property at any position within a subterranean region of ground encompassing at least two boreholes from which at least one crosswell seismic data profile is generated relating to said particular property, said method comprising the steps of:
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a) fitting a set of vertically spaced layer boundaries within and across said region encompassing said boreholes in a predetermined way such that a series of layers is defined between the layer boundaries;
b) establishing initial values of said particular property between said layer boundaries and across said subterranean region using a series of continuous analytic functions, at least one of which corresponds to each one of said series of layers; and
c) using said crosswell seismic profile or profiles, adjusting said continuous analytic functions to more closely match the value of said particular property across said subterranean region of ground such that the value of said particular property is determined for any selected point within said subterranean region. - View Dependent Claims (33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91)
d) performing a procedure to establish a new particular set of locations for each layer boundary based on the adjustment of said particular property and, thereafter, readjusting said continuous analytic functions using said new particular set of locations to still more closely match the value of said property across the subterranean region of ground.
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82. The method of claim 81 including the step of repeating step (d) in an iterative manner until such time that the continuous analytic functions are changed by less than a predetermined amount as compared with the previous iteration.
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83. The method of claim 32 wherein well logs are available for said boreholes and wherein said step of fitting said set of layer boundaries includes the steps of (i) establishing an intersection point of each layer with at least certain ones of said boreholes using said well logs and (ii) based on the borehole intersection points common to each layer, establishing each layer boundary extending across said subterranean region so as to extend through the common intersection points.
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84. The method of claim 83 wherein said step of fitting said layer boundaries further includes the step of establishing an intersection location of at least one layer with a specific location away from said boreholes at which specific location certain geologic data is known or can at least be estimated.
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85. The method of claim 83 wherein said certain geologic data is indicative of a strata boundary at said specific location within the subterranean region.
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86. The method of claim 83 wherein said layer boundaries are fitted and established using another series of continuous analytic functions, one of which corresponds to each layer boundary.
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87. The method of claim 86 wherein the other series of continuous analytic functions includes Chebychev polynomials including coefficients having magnitudes which are used to establish the intersection points of the boundary layers with the boreholes.
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88. The method of claim 83 wherein said well logs serve to identify a series of distinguishable formation tops common to each of said boreholes at different possible depths across the subterranean region and wherein said intersection points are selected for a particular one of said layer boundaries in correspondence with the series of formation tops so as to extend through the same distinguishable formation top at each of said boreholes.
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89. The method of claim 32 wherein said layer boundaries are defined using other continuous analytic functions.
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90. The method of claim 89 wherein said other continuous analytic functions are Chebychev polynomials.
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91. The method of claim 32 wherein an orthogonal coordinate system is established within said subterranean region including horizontal x and y axes and a vertical z axis and a ray segment terminates at a first point x1, y1 at depth z1 on a first layer boundary and terminates at a second point x2, y2 at depth z2 on a second, adjacent layer boundary such that the segment extends through one of said layers between the first and second points and wherein the slowness for said ray segment between the first and second points is given by the expression
Specification
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- Resources
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Current AssigneeZ-Seis Corp.
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Original AssigneeTomoseis, Inc.
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InventorsRector, James W. III, Bube, Kenneth P., Washbourne, John K.
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Primary Examiner(s)Brown, Glenn W.
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Assistant Examiner(s)JOLLY, ANTHONY S
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Application NumberUS09/152,935Time in Patent Office1,338 DaysField of Search367/34, 367/57, 367/72, 367/32, 367/14, 367/16, 367/25, 367/273, 367/38, 367/59, 367/35, 367/30, 367/69, 702/6, 702/14, 702/16, 702/7, 364/422, 524/335US Class Current367/73CPC Class CodesG01V 1/42 using generators in one wel...
