CN113009580B - Method and device for inverting VTI anisotropic parameters by variable offset VSP first arrival - Google Patents

Method and device for inverting VTI anisotropic parameters by variable offset VSP first arrival Download PDF

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CN113009580B
CN113009580B CN201911324743.3A CN201911324743A CN113009580B CN 113009580 B CN113009580 B CN 113009580B CN 201911324743 A CN201911324743 A CN 201911324743A CN 113009580 B CN113009580 B CN 113009580B
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vti
longitudinal wave
vertical velocity
wave vertical
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CN113009580A (en
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李建国
李飞
黄建华
李彦鹏
刘博�
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China National Petroleum Corp
BGP Inc
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BGP Inc
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
    • G01V1/00—Seismology; Seismic or acoustic prospecting or detecting
    • G01V1/40—Seismology; Seismic or acoustic prospecting or detecting specially adapted for well-logging
    • G01V1/44—Seismology; Seismic or acoustic prospecting or detecting specially adapted for well-logging using generators and receivers in the same well
    • G01V1/48—Processing data
    • G01V1/50—Analysing data
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
    • G01V1/00—Seismology; Seismic or acoustic prospecting or detecting
    • G01V1/28—Processing seismic data, e.g. for interpretation or for event detection
    • G01V1/282—Application of seismic models, synthetic seismograms
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
    • G01V1/00—Seismology; Seismic or acoustic prospecting or detecting
    • G01V1/28—Processing seismic data, e.g. for interpretation or for event detection
    • G01V1/30—Analysis
    • G01V1/303—Analysis for determining velocity profiles or travel times

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Abstract

The invention provides a method and a device for inverting VTI anisotropic parameters by variable offset VSP first arrival, wherein the method comprises the following steps: establishing a VTI longitudinal wave vertical velocity model according to the zero offset VSP first arrival; the method comprises the steps of ray tracing a forward VTI model, determining a variable offset VSP first-arrival travel time and a ray path of a VTI longitudinal wave vertical velocity model, and determining group velocities of group angles of each layer of group angles of the VTI model by combining with the time of the variable offset VSP actual measurement first-arrival travel; scanning a VTI model to obtain initial anisotropic parameters, determining a VTI model group velocity, searching best fit in the group velocities of all layer group angles of the VTI model, and determining intermediate anisotropic parameters; based on the intermediate anisotropic parameter, iterating ray tracing forward VTI model until the error between the travel time of the VTI model and the actual measurement of the variable offset VSP reaches a set value, and determining the final anisotropic parameter.

Description

Method and device for inverting VTI anisotropic parameters by variable offset VSP first arrival
Technical Field
The invention relates to the technical field of geophysical exploration, in particular to a method and a device for inverting VTI anisotropic parameters by variable offset VSP first arrival.
Background
In geophysical exploration, the processing of seismic data involves the category of vertical seismic processing techniques, in which VSP (VERTICAL SEISMIC Profiling) is a technique that is often used.
With the rapid development of well seismic technology in recent years, variable offset VSP (i.e., WALKAWAY VSP) has been implemented for industrial applications. Conventional hyperbolic moveout formulas based on isotropic and horizontal lamellar medium assumptions can produce non-negligible errors at the offset.
Studies have shown that the anisotropy of VTI (VERTICAL TRANSVERSE isotropy, a transversely isotropic medium with a vertical axis of symmetry) can more accurately characterize travel-time of the offset seismic waves. In the prior art, a technical scheme for inverting group velocity through chromatography and scanning VTI anisotropic parameters does not exist.
Disclosure of Invention
The embodiment of the invention provides a variable offset VSP first arrival inversion VTI anisotropic parameter method, which realizes the output of anisotropic parameters by chromatographic inversion of group velocity and scanning of a VTI longitudinal wave vertical velocity model, and comprises the following steps:
Establishing a VTI longitudinal wave vertical velocity model according to the zero offset VSP first arrival;
The ray tracing forward VTI longitudinal wave vertical velocity model is used for determining the variable offset VSP first arrival travel time and the ray path of the VTI longitudinal wave vertical velocity model;
according to the actual measurement of the variable offset VSP, the first-arrival travel time and the ray path of the variable offset VSP of the VTI longitudinal wave vertical velocity model, the tomographic inversion determines the group velocities of group angles of all layers of the VTI longitudinal wave vertical velocity model;
Scanning a VTI longitudinal wave vertical velocity model to obtain initial anisotropic parameters, and determining the group velocity of the VTI longitudinal wave vertical velocity model;
Searching the best fit of the group velocity of the VTI longitudinal wave vertical velocity model in the group velocity of each layer of group angle group of the VTI longitudinal wave vertical velocity model, and determining an intermediate anisotropic parameter;
Based on the intermediate anisotropic parameter, iterating ray tracing forward VTI longitudinal wave vertical velocity model until the error between the variable offset VSP first arrival travel time and the variable offset VSP actual measurement first arrival travel time of the VTI longitudinal wave vertical velocity model reaches a set value, and determining a final anisotropic parameter; according to the measured first-arrival travel time of the variable offset VSP and the variable offset VSP first-arrival travel time and ray paths of the VTI longitudinal wave vertical velocity model, the tomographic inversion determines group velocities of group angles of all layers of group angles of the VTI longitudinal wave vertical velocity model, and the method comprises the following steps:
Grouping group angle angles of group velocities of the VTI longitudinal wave vertical velocity model, and determining group angle center angles of the group angle groupings;
Establishing a chromatographic equation according to the actual measurement of the variable offset VSP in the first-arrival travel and the ray path of the VTI longitudinal wave vertical velocity model;
Solving a chromatographic equation according to least square, and determining a group slowness variation corresponding to the central angle of each group angle;
And updating the group velocity of the group angle central angles of each layer of group angle grouping according to the group slowness variation corresponding to each group angle central angle.
The embodiment of the invention also provides a device for inverting the VTI anisotropic parameter by the variable offset VSP first arrival, which comprises the following steps:
the VTI longitudinal wave vertical velocity model building module is used for building a VTI longitudinal wave vertical velocity model according to the zero offset VSP first arrival;
The VTI model first-arrival travel time and ray path determining module is used for ray tracing the forward VTI longitudinal wave vertical velocity model and determining the variable offset VSP first-arrival travel time and ray path of the VTI longitudinal wave vertical velocity model;
The chromatographic inversion module is used for determining group velocities of group angles of all layers of angles of the VTI longitudinal wave vertical velocity model according to the actual measurement of the variable offset VSP when the VTI longitudinal wave vertical velocity model arrives first, the variable offset VSP when the VTI longitudinal wave vertical velocity model arrives first and the ray path;
the VTI longitudinal wave vertical velocity model group velocity determining module is used for scanning the VTI longitudinal wave vertical velocity model to obtain initial anisotropic parameters and determining the VTI longitudinal wave vertical velocity model group velocity;
The middle anisotropic parameter determining module is used for searching the best fit of the VTI longitudinal wave vertical velocity model group velocity in the group angular group velocity of each layer group angle of the VTI longitudinal wave vertical velocity model and determining the middle anisotropic parameter;
The final anisotropic parameter determining module is used for iteratively ray tracing the forward VTI longitudinal wave vertical velocity model based on the intermediate anisotropic parameter until the error between the variable offset VSP of the VTI longitudinal wave vertical velocity model and the actual measurement of the variable offset VSP reaches a set value during first arrival travel, and determining the final anisotropic parameter; the chromatographic inversion module is specifically used for:
According to the measured first-arrival travel time of the variable offset VSP and the variable offset VSP first-arrival travel time and ray paths of the VTI longitudinal wave vertical velocity model, the tomographic inversion determines group velocities of group angles of all layers of group angles of the VTI longitudinal wave vertical velocity model, and the method comprises the following steps:
Grouping group angle angles of group velocities of the VTI longitudinal wave vertical velocity model, and determining group angle center angles of the group angle groupings;
Establishing a chromatographic equation according to the actual measurement of the variable offset VSP in the first-arrival travel and the ray path of the VTI longitudinal wave vertical velocity model;
Solving a chromatographic equation according to least square, and determining a group slowness variation corresponding to the central angle of each group angle;
And updating the group velocity of the group angle central angles of each layer of group angle grouping according to the group slowness variation corresponding to each group angle central angle.
The embodiment of the invention also provides computer equipment, which comprises a memory, a processor and a computer program stored on the memory and capable of running on the processor, wherein the processor realizes the method for inverting the VTI anisotropic parameters by the variable offset VSP first arrival when executing the computer program.
The embodiment of the invention also provides a computer readable storage medium which stores a computer program for executing the method for realizing the variable offset VSP first arrival inversion VTI anisotropic parameter.
According to the method and the device for inverting the VTI anisotropic parameters by the variable offset VSP first arrival, the VTI vertical velocity model is established according to the zero offset VSP first arrival, the variable offset VSP first arrival travel time and the ray path of the TI vertical velocity model are determined through ray tracing forward modeling, the decoupling problem of the anisotropic parameters is avoided by adopting the mode of obtaining the anisotropic parameters by chromatographic inversion of group angle and group velocity of each layer of group angle and scanning, the final anisotropic parameters can be directly obtained, the VTI parameters are provided for the follow-up processing and imaging of the variable offset VSP, and the seismic data processing in geophysical exploration is facilitated.
Drawings
In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, it being obvious that the drawings in the following description are only some embodiments of the invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art. In the drawings:
FIG. 1 is a schematic diagram of a method for inverting the VTI anisotropic parameters by varying offset VSP first arrival in accordance with an embodiment of the present invention.
FIG. 2 is a schematic illustration of a zero offset VSP first arrival of an example of a method for inverting the VTI anisotropy parameters for a variable offset VSP according to an embodiment of the invention.
FIG. 3 is a schematic diagram of a vertical velocity model of a VTI longitudinal wave established by an example of a method for inverting the anisotropic parameters of the VTI by a variable offset VSP according to an embodiment of the present invention.
FIG. 4 is a schematic diagram of a ray path of a VTI medium obtained by ray tracing in an example of a method for inverting the anisotropic parameters of VTI by a variable offset VSP according to an embodiment of the present invention.
FIG. 5 is a schematic diagram of a method for inverting the VTI anisotropy parameters for a first arrival of a variable offset VSP according to an embodiment of the invention.
Fig. 6 is a schematic diagram of an error between a first arrival trip time of a variable offset VSP and a first arrival trip time of a variable offset VSP of a VTI longitudinal wave vertical velocity model according to an example of a method for inverting VTI anisotropic parameters by a first arrival of the variable offset VSP according to an embodiment of the present invention.
FIG. 7 is a schematic diagram of a group slowness variation obtained by tomographic inversion in an example of a method for inverting VTI anisotropy parameters for a variable offset VSP according to an embodiment of the invention.
FIG. 8 is a schematic diagram of the group velocity before update of an example of a method for inverting the VTI anisotropy parameters for a variable offset VSP according to an embodiment of the invention.
FIG. 9 is a diagram of updated group velocity for an example of a method for inverting the VTI anisotropy parameters for a variable offset VSP according to an embodiment of the invention.
FIG. 10 is a schematic diagram of initial anisotropic parameters obtained by a scanned VTI longitudinal wave vertical velocity model for an example of a method for first-arrival inversion of VTI anisotropic parameters for a variable offset VSP according to an embodiment of the present invention.
Fig. 11 is a schematic diagram of standard deviation and mean between a first-arrival trip of a variable offset VSP and a measured first-arrival trip of the variable offset VSP of a VTI longitudinal wave vertical velocity model for 6 iterations of an example of a method for inverting VTI anisotropic parameters at a first-arrival of a variable offset VSP according to an embodiment of the present invention.
Fig. 12 is a schematic diagram of an error between a first-arrival trip time of a variable offset VSP and a measured first-arrival trip time of the variable offset VSP of a 6-iteration VTI longitudinal wave vertical velocity model according to an embodiment of the present invention.
FIG. 13 is a schematic diagram of the final anisotropy parameter ε of the VTI obtained by 6 iterations of an example of a method for first-arrival inversion of the VTI anisotropy parameter for a variable offset VSP according to an embodiment of the invention.
Fig. 14 is a schematic diagram of VTI final anisotropic parameters delta obtained by 6 iterations of an example of a method for first-arrival inversion of VTI anisotropic parameters for a variable offset VSP according to an embodiment of the present invention.
FIG. 15 is a schematic diagram of an apparatus for inverting the VTI anisotropy parameters for a variable offset VSP according to an embodiment of the invention.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the embodiments of the present invention will be described in further detail with reference to the accompanying drawings. The exemplary embodiments of the present invention and their descriptions herein are for the purpose of explaining the present invention, but are not to be construed as limiting the invention.
As shown in a schematic diagram of a variable offset VSP first-arrival inversion VTI anisotropic parameter method in the embodiment of the invention in FIG. 1, the embodiment of the invention provides a variable offset VSP first-arrival inversion VTI anisotropic parameter method, and the method realizes the output of anisotropic parameters by chromatographic inversion of group velocity and scanning of a VTI longitudinal wave vertical velocity model, and comprises the following steps:
Step 101: establishing a VTI longitudinal wave vertical velocity model according to the zero offset VSP first arrival;
step 102: the ray tracing forward VTI longitudinal wave vertical velocity model is used for determining the variable offset VSP first arrival travel time and the ray path of the VTI longitudinal wave vertical velocity model;
step 103: according to the actual measurement of the variable offset VSP, the first-arrival travel time and the ray path of the variable offset VSP of the VTI longitudinal wave vertical velocity model, the tomographic inversion determines the group velocities of group angles of all layers of the VTI longitudinal wave vertical velocity model;
step 104: scanning a VTI longitudinal wave vertical velocity model to obtain initial anisotropic parameters, and determining the group velocity of the VTI longitudinal wave vertical velocity model;
Step 105: searching the best fit of the group velocity of the VTI longitudinal wave vertical velocity model in the group velocity of each layer of group angle group of the VTI longitudinal wave vertical velocity model, and determining an intermediate anisotropic parameter;
Step 106: based on the intermediate anisotropic parameter, iterating ray tracing forward VTI longitudinal wave vertical velocity model until the error between the variable offset VSP first arrival travel time and the variable offset VSP actual measurement first arrival travel time of the VTI longitudinal wave vertical velocity model reaches a set value, and determining the final anisotropic parameter.
According to the variable offset VSP first-arrival inversion VTI anisotropic parameter method provided by the embodiment of the invention, a VTI longitudinal wave vertical velocity model is established according to the zero offset VSP first-arrival, the variable offset VSP first-arrival travel time and the ray path of the TI longitudinal wave vertical velocity model are determined through ray tracing forward modeling, and further decoupling of anisotropic parameters is avoided by adopting a mode of chromatographic inversion of group angular group velocities of all layers and scanning to acquire anisotropic parameters, final anisotropic parameters can be directly acquired, VTI parameters are provided for subsequent processing and imaging of the variable offset VSP, and seismic data processing in geophysical exploration is facilitated.
When the method for inverting the VTI anisotropic parameter by the variable offset VSP first arrival provided by the embodiment of the invention is implemented, the method can comprise the following steps: establishing a VTI longitudinal wave vertical velocity model according to the zero offset VSP first arrival; the ray tracing forward VTI longitudinal wave vertical velocity model is used for determining the variable offset VSP first arrival travel time and the ray path of the VTI longitudinal wave vertical velocity model; according to the actual measurement of the variable offset VSP, the first-arrival travel time and the ray path of the variable offset VSP of the VTI longitudinal wave vertical velocity model, the tomographic inversion determines the group velocities of group angles of all layers of the VTI longitudinal wave vertical velocity model; scanning a VTI longitudinal wave vertical velocity model to obtain initial anisotropic parameters, and determining the group velocity of the VTI longitudinal wave vertical velocity model; searching the best fit of the group velocity of the VTI longitudinal wave vertical velocity model in the group velocity of each layer of group angle group of the VTI longitudinal wave vertical velocity model, and determining an intermediate anisotropic parameter; based on the intermediate anisotropic parameter, iterating ray tracing forward VTI longitudinal wave vertical velocity model until the error between the variable offset VSP first arrival travel time and the variable offset VSP actual measurement first arrival travel time of the VTI longitudinal wave vertical velocity model reaches a set value, and determining the final anisotropic parameter.
In an embodiment, the establishing the VTI longitudinal wave vertical velocity model according to the first arrival of the zero offset VSP may include:
determining a vertical single pass according to the first arrival of the zero offset VSP;
And determining the vertical velocity of the VTI longitudinal wave according to the vertical single pass, and establishing a VTI longitudinal wave vertical velocity model.
The embodiment of the invention also provides a specific example of the variable offset VSP first-arrival inversion VTI anisotropic parameter method, as shown in a zero offset VSP first-arrival schematic diagram of an example of the variable offset VSP first-arrival inversion VTI anisotropic parameter method in the embodiment of the invention, in the example of the embodiment of the invention, the zero offset VSP first-arrival is shown by taking the abscissa as the first-arrival time (unit: s) and the ordinate as the depth (unit: m).
In practicing one of the variable offset VSP first arrival inversion VTI anisotropy parameter methods described above, in one embodiment, the vertical single pass may be determined as follows:
where H i is the ith detector depth, t i is the ith first arrival, offset is the distance from the wellhead for the zero Offset VSP shot, and t vi is the ith vertical single pass.
The foregoing expressions for determining the vertical single pass are exemplary, and those skilled in the art will appreciate that the above-described expressions may be modified and added with other parameters or data as needed, or that other specific expressions may be provided, and that such modifications are within the scope of the invention.
In implementing the above-described method for inverting the VTI anisotropic parameters at first arrival of a variable offset VSP, in one embodiment, the VTI longitudinal wave vertical velocity may be determined as follows:
VP0,i＝(Hi-Hi-1)/(tvi-tvi-1)
Where H i-1 is the i-1 th detector depth, H i is the i-1 th detector depth, t vi-1 is the vertical single pass of the i-1 th detector, t vi is the vertical single pass of the i-th detector, and V P0,i is the VTI longitudinal wave vertical velocity of the i-th layer.
The above-mentioned expression for determining the vertical velocity of the VTI longitudinal wave is given as an example, and it will be understood by those skilled in the art that the above-mentioned expression may be modified and other parameters or data may be added to the above-mentioned expression in some form or other specific expression may be provided as needed, and all such modifications fall within the scope of the present invention.
The embodiment of the invention also provides a specific example of the variable offset VSP first-arrival inversion VTI anisotropic parameter method, as shown in a schematic diagram of a VTI longitudinal wave vertical velocity model established by an example of the variable offset VSP first-arrival inversion VTI anisotropic parameter method in the embodiment of the invention in fig. 3, in the example of the embodiment of the invention, the established VTI longitudinal wave vertical velocity model is illustrated by using the abscissa as the longitudinal wave vertical velocity (V P0) (unit: m/s) and the ordinate as the depth (unit: m).
In an embodiment, when implementing the method for inverting the VTI anisotropic parameter by using the variable offset VSP first arrival, the determining the variable offset VSP first arrival travel time and the ray path of the VTI longitudinal wave vertical velocity model by using the ray tracing forward VTI longitudinal wave vertical velocity model may include:
Step 201: setting an initial phase angle of a VTI longitudinal wave vertical velocity model; the initial phase angle can be the initial phase angle of the known shot point position;
Step 202: determining an initial phase velocity, an initial group velocity and an initial group angle according to the initial phase angle;
step 203: propagating the rays along the initial group angle phi direction, and calculating the intersection point of the rays and the interface;
step 204: performing transmission processing by Snell law at the intersection point of the interface, and calculating a transmission phase angle;
step 205: based on the projection phase angle, iterating the initial phase angle layer by layer until the rays reach the well track, and determining the ray paths and the iterative group velocity;
Step 206: and determining the variable offset VSP first arrival travel time of the VTI longitudinal wave vertical velocity model according to the ray path and the iterative group velocity.
The step 205 is based on the projected phase angle, and the initial phase angle is iterated layer by layer, which may be, in an embodiment, iterating the steps 202-204 after obtaining the projected phase angle; stopping iteration until the ray reaches the well track, and determining the ray path and the group velocity of the iteration as the ray path and the group velocity after the iteration.
In implementing a variable offset VSP first arrival inversion VTI anisotropic parameter method as described above, in one embodiment, the initial phase velocity may be determined as follows:
VP(θ)＝VP0(1+δsin2θcos2θ+εsin4θ)
Where θ is the initial phase angle, ε, δ are the VTI media anisotropy parameters, V P0 is the VTI longitudinal wave vertical velocity, and V P (θ) is the initial phase velocity of the longitudinal wave corresponding to the initial phase angle θ.
The above-mentioned expression for determining the initial phase velocity is given as an example, and it will be understood by those skilled in the art that the above-mentioned expression may be modified and other parameters or data may be added according to the need, or other specific expressions may be provided, and these modifications are within the scope of the present invention.
In practicing a variable offset VSP first arrival inversion VTI anisotropy parameter method as described above, in one embodiment, the initial group velocity may be determined as follows:
where θ is the initial phase angle, φ is the initial group angle, V P (θ) is the initial phase velocity, and V g (φ) is the initial group velocity.
The above-mentioned expressions for determining the initial group velocity are given by way of example, and it will be understood by those skilled in the art that the above-mentioned expressions may be modified and other parameters or data may be added as desired or other specific expressions may be provided, and such modifications are intended to fall within the scope of the invention.
In implementing the above-described method for inverting the VTI anisotropic parameters at first arrival of a variable offset VSP, in one embodiment, the initial group angle may be determined as follows:
where θ is the initial phase angle, φ is the initial group angle, V P (θ) is the initial phase velocity, and V g (φ) is the initial group velocity.
The foregoing expressions for determining the initial group angles are given by way of example, and it will be understood by those skilled in the art that the foregoing formulas may be modified and other parameters or data may be added as desired or other specific formulas may be provided, and such modifications are intended to fall within the scope of the present invention.
When the method for inverting the VTI anisotropic parameter by the first arrival of the variable offset VSP is implemented, in one embodiment, the transmission processing is performed by Snell's law at the intersection point of the interfaces, and the Snell's law involved in the process of calculating the transmission phase angle is as follows:
Where θ 1 is the incident phase angle, V P(θ1) is the incident phase velocity, θ 2 is the transmitted phase angle, V P(θ2) is the transmitted phase velocity.
The above-mentioned expression of Snell's law is given as an example, and those skilled in the art will understand that the above-mentioned expression may be modified and other parameters or data may be added according to the need, or other specific formulas may be provided, and these modifications shall fall within the protection scope of the present invention.
In the implementation of the method for first-arrival inversion of VTI anisotropic parameters by using a variable offset VSP, in one embodiment, the following manner may be used to determine when the variable offset VSP of the VTI longitudinal wave vertical velocity model travels:
Where n is the number of ray path segments, l i is the ith ray segment traced by the ray path, V gi is the group velocity corresponding to the ith ray segment, and T tra is the first arrival trip corresponding to the ray path.
The above-mentioned expressions for determining the first-arrival travel of the variable offset VSP of the VTI longitudinal wave vertical velocity model are given by way of example, and it will be understood by those skilled in the art that the above-mentioned expressions may be modified and other parameters or data may be added to the above-mentioned expressions or other specific expressions may be provided as needed, and these modifications fall within the scope of the present invention.
The embodiment of the invention also provides a specific example of the variable offset VSP first-arrival inversion VTI anisotropic parameter method, as shown in a schematic diagram of a VTI medium ray path obtained by ray tracing in an example of the variable offset VSP first-arrival inversion VTI anisotropic parameter method in the embodiment of the invention in fig. 4, in the example of the embodiment of the invention, the ray path of the VTI medium obtained by ray tracing is shown by using an abscissa as a model X coordinate (unit: m) and an ordinate as a model Z coordinate (unit: m).
In an embodiment, in implementing the method for inverting the VTI anisotropic parameter by using the variable offset VSP first arrival, determining the group velocities of the group angles of each layer of the VTI longitudinal wave vertical velocity model by using the tomographic inversion according to the variable offset VSP actual measurement first arrival travel time and the variable offset VSP first arrival travel time and the ray path of the VTI longitudinal wave vertical velocity model may include:
Grouping group angle angles of group velocities of the VTI longitudinal wave vertical velocity model, and determining group angle center angles of the group angle groupings;
Establishing a chromatographic equation according to the actual measurement of the variable offset VSP in the first-arrival travel and the ray path of the VTI longitudinal wave vertical velocity model;
Solving a chromatographic equation according to least square, and determining a group slowness variation corresponding to the central angle of each group angle;
And updating the group velocity of the group angle central angles of each layer of group angle grouping according to the group slowness variation corresponding to each group angle central angle.
In implementing the above-described method for inverting the VTI anisotropic parameters at first arrival of a variable offset VSP, in one embodiment, the group angle groupings may be performed as follows:
φci-Δφ＜φi≤φci+Δφ
Where φ i is the ith group angle, φ ci is the group angle center angle of the ith group, Δφ is the grouping range.
The foregoing expressions for grouping the group angles are given by way of example, and those skilled in the art will understand that the foregoing formulas may be modified and added with other parameters or data in a certain manner, or other specific formulas may be provided, as needed, and all such modifications are within the scope of the present invention.
In implementing the above-described method for inverting the VTI anisotropic parameters at first arrival of a variable offset VSP, in one embodiment, the chromatographic equation may be established as follows:
ΔT＝Ttra-TVSP
LM×N·ΔSN×1＝ΔTM×1
Wherein L is the path of the ray path in each layer, delta S is the group slowness variation corresponding to the central angle of each group angle, M is the number of ray paths, N is the number of group angle groups, and T tra is the variable offset VSP of the VTI longitudinal wave vertical velocity model when traveling first; t VSP is the time of the actual measurement of the variable offset VSP first arrival travel; delta T is the error between when the variable offset VSP of the VTI longitudinal wave vertical velocity model first-arrival travel and when the variable offset VSP actually measures first-arrival travel.
The foregoing expressions for establishing the chromatographic equations are given by way of example, and it will be understood by those skilled in the art that the foregoing equations may be modified and other parameters or data may be added as desired or provided in other specific formulations, and that such modifications are within the scope of the invention.
The embodiment of the invention also provides a specific example of the variable offset VSP first-arrival inversion VTI anisotropic parameter method, as shown in a schematic diagram of the variable offset VSP actual measurement first-arrival travel time of an example of the variable offset VSP first-arrival inversion VTI anisotropic parameter method in the embodiment of the invention, in the example of the embodiment of the invention, the moment of the variable offset VSP actual measurement first-arrival travel time is shown by taking the abscissa as the shot number (unit: none) and the ordinate as the first-arrival time (unit: s). As shown in the error diagram between the first-arrival travel time of the variable offset VSP and the actual measurement first-arrival travel time of the variable offset VSP of the VTI longitudinal wave vertical velocity model in an example of the method for inverting the VTI anisotropic parameters by the variable offset VSP according to the embodiment of the present invention, in the example of the embodiment of the present invention, the error between the first-arrival travel time of the variable offset VSP and the actual measurement first-arrival travel time of the variable offset VSP of the VTI longitudinal wave vertical velocity model is shown by using the abscissa as the shot number (unit: none) and the ordinate as the first-arrival error (unit: ms). As shown in FIG. 7, in an example of a method for inverting the VTI anisotropic parameters by using a variable offset VSP first arrival in accordance with the present invention, in the example of the present invention, the group slowness variation obtained by the tomographic inversion is illustrated by using the abscissa as the angle (unit: °) and the ordinate as the group slowness variation (unit: s/m).
In implementing the above-described method for first-arrival inversion of VTI anisotropic parameters by variable offset VSP, in one embodiment, the group velocity of the group angle center angle of each layer group angle group may be updated as follows:
Wherein phi ci is the group angle center angle of the i-th group, deltaS i is the group slowness variation corresponding to the group angle center angle of the i-th group, V g(φci) the group velocity of the group angle center angle of the i-th group, old is updated, new is updated.
The above-mentioned expressions for updating the group velocity of the group angle center angle of each layer group angle group are given by way of example, and it will be understood by those skilled in the art that the above-mentioned formulas may be modified and other parameters or data may be added to or provided with other specific formulas in a manner as desired, and these modifications fall within the scope of the present invention.
The embodiment of the invention also provides a specific example of the variable offset VSP first-arrival inversion VTI anisotropic parameter method, as shown in a group velocity schematic diagram before updating an example of the variable offset VSP first-arrival inversion VTI anisotropic parameter method in the embodiment of the invention, in the example of the embodiment of the invention, the group velocity before updating is shown by taking the abscissa as an angle (unit: °) and the ordinate as a group velocity (unit: m/s). As shown in fig. 9, an updated group velocity diagram of an example of a method for inverting VTI anisotropic parameters by first arrival at a variable offset VSP according to an embodiment of the present invention, in the example of the present invention, the updated group velocity is illustrated with an angle (unit: °) on the abscissa and a group velocity (unit: m/s) on the ordinate.
In an embodiment, when implementing the method for inverting the VTI anisotropic parameter by using the variable offset VSP first arrival method, scanning the VTI vertical velocity model to obtain the initial anisotropic parameter, and determining the VTI vertical velocity model group velocity may include:
Setting a scanning range and a scanning step length, and scanning a VTI longitudinal wave vertical velocity model to obtain initial anisotropic parameters;
And determining the group velocity of the VTI longitudinal wave vertical velocity model according to the initial anisotropic parameter and the VTI longitudinal wave vertical velocity model.
In an embodiment of implementing the above method for inverting the VTI anisotropic parameter by using the variable offset VSP first arrival, the anisotropic parameter may include: delta and epsilon are dimensionless parameters; in an embodiment, an exhaustive method can be adopted for scanning the VTI longitudinal wave vertical velocity model; in an embodiment, the scan range and the scan step size may be set as follows:
εk＝εmin+(k-1)Δε,ε∈[εmin,εmax],k∈[1,(εmax-εmin)/Δε+1]
δl＝δmin+(l-1)Δδ,δ∈[δmin,δmax],l∈[1,(δmax-δmin)/Δδ+1]
Here, epsilon min、εmax and delta epsilon are the scanning range and step length of epsilon, delta min、δmax and delta are the scanning range and step length of delta, and k and l are the number of cycles.
The foregoing expressions for setting the scanning range and the scanning step size are given as examples, and those skilled in the art will understand that the foregoing formulas may be modified and added with other parameters or data according to the needs, or other specific formulas may be provided, and these modifications are within the scope of the present invention.
The embodiment of the invention also provides a specific example of the variable offset VSP first-arrival inversion VTI anisotropic parameter method, as shown in an initial anisotropic parameter schematic diagram obtained by a scanning VTI longitudinal wave vertical velocity model of an example of the variable offset VSP first-arrival inversion VTI anisotropic parameter method in the embodiment of the invention in fig. 10, in the example of the embodiment of the invention, the initial anisotropic parameter obtained by the scanning VTI longitudinal wave vertical velocity model is shown by delta (unit: none) on the abscissa and epsilon (unit: none) on the ordinate.
In implementing the above-described method for inverting the VTI anisotropic parameters at first arrival of a variable offset VSP, in one embodiment, the VTI longitudinal wave vertical velocity model group velocity may be determined as follows:
Wherein, θ ci is the phase angle corresponding to the group angle φ ci, V P,kl(θci) is the phase velocity with the anisotropy parameter ε k、δl and the phase angle θ ci, and V g,kl(φci) is the VTI longitudinal wave vertical velocity model group velocity with the anisotropy parameter ε k、δl and the group angle φ ci.
The above-mentioned expressions for determining the group velocity of the VTI longitudinal wave vertical velocity model are given by way of example, and it will be understood by those skilled in the art that the above-mentioned expressions may be modified and other parameters or data may be added to or provided with other specific expressions as needed and as desired, and all such modifications fall within the scope of the present invention.
In an embodiment, the method for implementing the above-mentioned method for inverting the VTI anisotropic parameter by using the variable offset VSP first arrival may further include searching for a best fit of the VTI vertical velocity model group velocity in the group angular group velocities of each layer of the VTI vertical velocity model, and determining the intermediate anisotropic parameter, where the method may include:
Calculating errors between the group velocities of the VTI longitudinal wave vertical velocity model and the group velocities of the angle groups of each layer of the VTI longitudinal wave vertical velocity model;
searching the minimum value of the error, and determining the minimum value as the best fitting group velocity of the VTI longitudinal wave vertical velocity model group velocity in the group angular grouping group velocity of each layer of the VTI longitudinal wave vertical velocity model;
And determining the anisotropic parameter corresponding to the best fit group velocity as an intermediate anisotropic parameter.
In an embodiment of the method for implementing the variable offset VSP first arrival inversion VTI anisotropic parameter, the error includes: standard deviation and mean;
The standard deviation between the group velocity of the VTI longitudinal wave vertical velocity model and the group velocity of each layer group angle packet of the VTI longitudinal wave vertical velocity model can be calculated as follows:
Wherein, Group velocity with a group angle phi ci of the vertical velocity model of the vertical velocity of the vertical wave of VTI, V g,kl(φci) is group velocity with an anisotropy parameter epsilon k、δl and group angles phi ci VTI, V std,kl is standard deviation of group velocity with an anisotropy parameter epsilon k、δl.
The above-mentioned expression for calculating the standard deviation between the group velocity of the VTI longitudinal wave vertical velocity model and the group velocity of each layer group angle group of the VTI longitudinal wave vertical velocity model is taken as an example, and it will be understood by those skilled in the art that the above-mentioned expression may be modified and other parameters or data may be added according to the need, or other specific formulas may be provided, and these modified examples shall fall within the scope of the present invention.
The embodiment of the invention also provides a specific example of the variable offset VSP first-arrival inversion VTI anisotropic parameter method, as shown in a standard deviation and average value schematic diagram between the variable offset VSP first-arrival travel time and the variable offset VSP actual measurement first-arrival travel time of a VTI longitudinal wave vertical velocity model in 6 iterations of an example of the variable offset VSP first-arrival inversion VTI anisotropic parameter method in the embodiment of the invention, in the example of the embodiment of the invention, 6 iterations are performed, the standard deviation and average value obtained after 6 iterations are shown in the standard deviation and average value actual measurement between the variable offset VSP first-arrival travel time and the variable offset VSP first-arrival travel time of the VTI longitudinal wave vertical velocity model by taking the abscissa as the iteration times (unit: none) and the ordinate as the error (unit: s) of the first-arrival in FIG. 11. According to the standard deviation and the mean value between the first arrival trip time of the variable offset VSP and the actual measurement first arrival trip time of the variable offset VSP of the VTI longitudinal wave vertical velocity model, the error between the first arrival trip time of the variable offset VSP and the actual measurement first arrival trip time of the variable offset VSP of the VTI longitudinal wave vertical velocity model can be obtained, as shown in the error schematic diagram between the first arrival trip time of the variable offset VSP and the actual measurement first arrival trip time of the VTI longitudinal wave vertical velocity model of 6 iterations of the method for inverting VTI anisotropic parameters by the variable offset VSP according to the embodiment of fig. 12, in the embodiment of the invention, the error between the first arrival trip time of the variable offset VSP and the actual measurement first arrival trip time of the VTI longitudinal wave vertical velocity model of 6 iterations is shown by the abscissa (unit: no) and the error (unit: ms) of the first arrival time of the variable offset VSP.
In an embodiment, the method for performing the first arrival inversion of the VTI anisotropic parameter by using the variable offset VSP is based on an intermediate anisotropic parameter, and iterating the ray tracing forward VTI longitudinal wave vertical velocity model until an error between the first arrival trip time of the variable offset VSP and the actual measurement first arrival trip time of the variable offset VSP of the VTI longitudinal wave vertical velocity model reaches a set value, so as to determine a final anisotropic parameter; further, the iterative ray tracing forward VTI longitudinal wave vertical velocity model is based on the intermediate anisotropic parameter obtained for the first time, and the steps 102-105 are repeated until the error between the initial arrival travel time of the variable offset VSP of the VTI longitudinal wave vertical velocity model and the actual measurement initial arrival travel time of the variable offset VSP reaches a set value, so as to determine the final anisotropic parameter. The error set value between the first arrival travel time of the variable offset VSP of the VTI longitudinal wave vertical velocity model and the actual measurement first arrival travel time of the variable offset VSP can be determined by the processing precision required by the subsequent processing of the variable offset VSP in the concrete implementation; in the embodiment, when the error between the first arrival travel time of the variable offset VSP of the VTI longitudinal wave vertical velocity model and the actual measurement first arrival travel time of the variable offset VSP reaches a set value, stopping iteration, and determining an intermediate anisotropic parameter corresponding to the best fit of the current VTI longitudinal wave vertical velocity model group velocity in the group angular group velocities of each layer of the VTI longitudinal wave vertical velocity model as a final anisotropic parameter.
The embodiment of the invention also provides a specific example of the variable offset VSP first-arrival inversion VTI anisotropic parameter method, as shown in a schematic diagram of a VTI final anisotropic parameter epsilon obtained by 6 iterations of an example of the variable offset VSP first-arrival inversion VTI anisotropic parameter method in the embodiment of the invention in FIG. 13, in the example of the embodiment of the invention, 6 iterations are performed, and the VTI final anisotropic parameter epsilon obtained by 6 iterations is shown in FIG. 13 by using epsilon (unit: none) as an abscissa and depth (unit: m) as an ordinate. As shown in fig. 14, in the example of the embodiment of the present invention, 6 iterations are performed to obtain the final anisotropic parameter δ of the VTI obtained by 6 iterations, and in fig. 14, the final anisotropic parameter δ of the VTI obtained by 6 iterations is shown with the abscissa δ (unit: none) and the ordinate depth (unit: m) in fig. 14.
The embodiment of the invention also provides computer equipment, which comprises a memory, a processor and a computer program stored on the memory and capable of running on the processor, wherein the processor realizes the method for inverting the VTI anisotropic parameters by the variable offset VSP first arrival when executing the computer program.
The embodiment of the invention also provides a computer readable storage medium which stores a computer program for executing the method for realizing the variable offset VSP first arrival inversion VTI anisotropic parameter.
The embodiment of the invention also provides a device for inverting the VTI anisotropic parameter by the variable offset VSP first arrival, which is described in the following embodiment. Because the principle of the device for solving the problem is similar to that of a variable offset VSP first-arrival inversion VTI anisotropic parameter method, the implementation of the device can be referred to the implementation of a variable offset VSP first-arrival inversion VTI anisotropic parameter method, and the repetition is not repeated.
As shown in a schematic diagram of a variable offset VSP first-arrival inversion VTI anisotropic parameter device in the embodiment of the present invention in fig. 15, the embodiment of the present invention further provides a variable offset VSP first-arrival inversion VTI anisotropic parameter device, including:
the VTI longitudinal wave vertical velocity model building module 1501 is configured to build a VTI longitudinal wave vertical velocity model according to the zero offset VSP first arrival;
the VTI model first-arrival travel time and ray path determining module 1502 is configured to ray-track the forward VTI longitudinal wave vertical velocity model, and determine a variable offset VSP first-arrival travel time and ray path of the VTI longitudinal wave vertical velocity model;
the tomographic inversion module 1053 is configured to determine group velocities of group angles of each layer of angles of the vertical velocity model of the VTI longitudinal wave according to the measured first-arrival travel time of the variable offset VSP and the variable offset VSP first-arrival travel time and the ray path of the vertical velocity model of the VTI longitudinal wave;
The VTI longitudinal wave vertical velocity model group velocity determination module 1054 is configured to scan the VTI longitudinal wave vertical velocity model to obtain initial anisotropic parameters and determine VTI longitudinal wave vertical velocity model group velocities;
the middle anisotropic parameter determining module 1505 is configured to find a best fit of the group velocity of the VTI longitudinal wave vertical velocity model in the group velocities of the group angles of each layer of the VTI longitudinal wave vertical velocity model, and determine a middle anisotropic parameter;
The final anisotropic parameter determining module 1506 is configured to iterate ray tracing the forward VTI longitudinal wave vertical velocity model based on the intermediate anisotropic parameter until an error between a first arrival trip time of the variable offset VSP of the VTI longitudinal wave vertical velocity model and a first arrival trip time of the variable offset VSP is actually measured reaches a set value, and determine a final anisotropic parameter.
In one embodiment, the VTI longitudinal wave vertical velocity model building module is specifically configured to:
determining a vertical single pass according to the first arrival of the zero offset VSP;
And determining the vertical velocity of the VTI longitudinal wave according to the vertical single pass, and establishing a VTI longitudinal wave vertical velocity model.
In one embodiment, the VTI longitudinal wave vertical velocity modeling module is further configured to determine a vertical single pass as follows:
where H i is the ith detector depth, t i is the ith first arrival, offset is the distance from the wellhead for the zero Offset VSP shot, and t vi is the ith vertical single pass.
In one embodiment, the VTI longitudinal wave vertical velocity model building module is further configured to determine the VTI longitudinal wave vertical velocity as follows:
VP0,i＝(Hi-Hi-1)/(tvi-tvi-1)
Where H i-1 is the i-1 th detector depth, H i is the i-1 th detector depth, t vi-1 is the vertical single pass of the i-1 th detector, t vi is the vertical single pass of the i-th detector, and V P0,i is the VTI longitudinal wave vertical velocity of the i-th layer.
In one embodiment, the VTI model first-arrival travel time and ray path determination module is specifically configured to:
Setting an initial phase angle of a VTI longitudinal wave vertical velocity model;
determining an initial phase velocity, an initial group velocity and an initial group angle according to the initial phase angle;
propagating the rays along the initial group angle direction, and calculating the intersection point of the rays and the interface;
performing transmission processing by Snell law at the intersection point of the interface, and calculating a transmission phase angle;
Based on the projection phase angle, iterating the initial phase angle layer by layer until the rays reach the well track, and determining the ray paths and the iterative group velocity;
And determining the variable offset VSP first arrival travel time of the VTI longitudinal wave vertical velocity model according to the ray path and the iterative group velocity.
In one embodiment, the VTI model first-trip and ray path determination module is further configured to determine the initial phase velocity as follows:
VP(θ)＝VP0(1+δsin2θcos2θ+εsin4θ)
Where θ is the initial phase angle, ε, δ are the VTI media anisotropy parameters, V P0 is the VTI longitudinal wave vertical velocity, and V P (θ) is the initial phase velocity of the longitudinal wave corresponding to the initial phase angle θ.
In one embodiment, the VTI model first-arrival travel time and ray path determination module is further configured to determine the initial group velocity as follows:
where θ is the initial phase angle, φ is the initial group angle, V P (θ) is the initial phase velocity, and V g (φ) is the initial group velocity.
In one embodiment, the VTI model first-arrival travel time and ray path determination module is further configured to determine the initial group angle as follows:
where θ is the initial phase angle, φ is the initial group angle, V P (θ) is the initial phase velocity, and V g (φ) is the initial group velocity.
In one embodiment, the VTI model first-arrival trip and ray path determining module performs transmission processing by Snell's law at the intersection point of the interfaces, and the Snell's law involved in calculating the transmission phase angle is:
Where θ 1 is the incident phase angle, V P(θ1) is the incident phase velocity, θ 2 is the transmitted phase angle, V P(θ2) is the transmitted phase velocity.
In one embodiment, the VTI model first-arrival trip and ray path determination module is further configured to determine a variable offset VSP first-arrival trip of the VTI longitudinal wave vertical velocity model as follows:
Where n is the number of ray path segments, l i is the ith ray segment traced by the ray path, V gi is the group velocity corresponding to the ith ray segment, and T tra is the first arrival trip corresponding to the ray path.
In one embodiment, the tomographic inversion module is specifically configured to:
Grouping group angle angles of group velocities of the VTI longitudinal wave vertical velocity model, and determining group angle center angles of the group angle groupings;
Establishing a chromatographic equation according to the actual measurement of the variable offset VSP in the first-arrival travel and the ray path of the VTI longitudinal wave vertical velocity model;
Solving a chromatographic equation according to least square, and determining a group slowness variation corresponding to the central angle of each group angle;
And updating the group velocity of the group angle central angles of each layer of group angle grouping according to the group slowness variation corresponding to each group angle central angle.
In one embodiment, the tomographic inversion module is further configured to group the group angle angles as follows:
φci-Δφ＜φi≤φci+Δφ
Where φ i is the ith group angle, φ ci is the group angle center angle of the ith group, Δφ is the grouping range.
In one embodiment, the tomographic inversion module is further configured to establish a tomographic equation as follows:
ΔT＝Ttra-TVSP
LM×N·ΔSN×1＝ΔTM×1
Wherein L is the path of the ray path in each layer, delta S is the group slowness variation corresponding to the central angle of each group angle, M is the number of ray paths, N is the number of group angle groups, and T tra is the variable offset VSP of the VTI longitudinal wave vertical velocity model when traveling first; t VSP is the time of the actual measurement of the variable offset VSP first arrival travel; delta T is the error between when the variable offset VSP of the VTI longitudinal wave vertical velocity model first-arrival travel and when the variable offset VSP actually measures first-arrival travel.
In one embodiment, the tomographic inversion module is further configured to update the group velocity of the group angle center angle of each layer group angle group as follows:
Wherein phi ci is the group angle center angle of the i-th group, deltaS i is the group slowness variation corresponding to the group angle center angle of the i-th group, V g(φci) the group velocity of the group angle center angle of the i-th group, old is updated, new is updated.
In one embodiment, the VTI longitudinal wave vertical velocity model group velocity determination module is specifically configured to:
Setting a scanning range and a scanning step length, and scanning a VTI longitudinal wave vertical velocity model to obtain initial anisotropic parameters;
And determining the group velocity of the VTI longitudinal wave vertical velocity model according to the initial anisotropic parameter and the VTI longitudinal wave vertical velocity model.
In one embodiment, the VTI longitudinal wave vertical velocity model group velocity determination module is further configured to set the scan range and the scan step size as follows:
εk＝εmin+(k-1)Δε,ε∈[εmin,εmax],k∈[1,(εmax-εmin)/Δε+1]
δl＝δmin+(l-1)Δδ,δ∈[δmin,δmax],l∈[1,(δmax-δmin)/Δδ+1]
Here, epsilon min、εmax and delta epsilon are the scanning range and step length of epsilon, delta min、δmax and delta are the scanning range and step length of delta, and k and l are the number of cycles.
In one embodiment, the VTI longitudinal wave vertical velocity model group velocity determination module is further configured to determine the VTI longitudinal wave vertical velocity model group velocity as follows:
Wherein, θ ci is the phase angle corresponding to the group angle φ ci, V P,kl(θci) is the phase velocity with the anisotropy parameter ε k、δl and the phase angle θ ci, and V g,kl(φci) is the VTI longitudinal wave vertical velocity model group velocity with the anisotropy parameter ε k、δl and the group angle φ ci.
In one embodiment, the intermediate anisotropic parameter determination module is specifically configured to:
Calculating errors between the group velocities of the VTI longitudinal wave vertical velocity model and the group velocities of the angle groups of each layer of the VTI longitudinal wave vertical velocity model;
searching the minimum value of the error, and determining the minimum value as the best fitting group velocity of the VTI longitudinal wave vertical velocity model group velocity in the group angular grouping group velocity of each layer of the VTI longitudinal wave vertical velocity model;
And determining the anisotropic parameter corresponding to the best fit group velocity as an intermediate anisotropic parameter.
In one embodiment, the error comprises: standard deviation and mean;
The intermediate anisotropic parameter determining module is further configured to calculate a standard deviation between the group velocity of the VTI longitudinal wave vertical velocity model and the group velocity of each layer group angle packet of the VTI longitudinal wave vertical velocity model according to the following manner:
Wherein, Group velocity with a group angle phi ci of the vertical velocity model of the vertical velocity of the vertical wave of VTI, V g,kl(φci) is group velocity with an anisotropy parameter epsilon k、δl and group angles phi ci VTI, V std,kl is standard deviation of group velocity with an anisotropy parameter epsilon k、δl.
In summary, the method and the device for inverting the anisotropic parameters of the VTI by the variable offset VSP first arrival establish the VTI longitudinal wave vertical velocity model according to the zero offset VSP first arrival, determine the variable offset VSP first arrival travel time and the ray path of the TI longitudinal wave vertical velocity model through ray tracing forward modeling, further avoid the decoupling problem of the anisotropic parameters by adopting the mode of obtaining the anisotropic parameters by chromatographic inversion of group angle group velocity and scanning of each layer of group angle, directly obtain final anisotropic parameters, provide the VTI parameters for the follow-up processing and imaging of the variable offset VSP, and are beneficial to seismic data processing in geophysical exploration.
It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as a method, system, or computer program product. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.
The present invention is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flowchart illustrations and/or block diagrams, and combinations of flows and/or blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
The foregoing description of the embodiments has been provided for the purpose of illustrating the general principles of the invention, and is not meant to limit the scope of the invention, but to limit the invention to the particular embodiments, and any modifications, equivalents, improvements, etc. that fall within the spirit and principles of the invention are intended to be included within the scope of the invention.

Claims (20)

1. A method for inverting VTI anisotropic parameters at first arrival of a variable offset VSP, comprising:
Establishing a VTI longitudinal wave vertical velocity model according to the zero offset VSP first arrival;
The ray tracing forward VTI longitudinal wave vertical velocity model is used for determining the variable offset VSP first arrival travel time and the ray path of the VTI longitudinal wave vertical velocity model;
according to the actual measurement of the variable offset VSP, the first-arrival travel time and the ray path of the variable offset VSP of the VTI longitudinal wave vertical velocity model, the tomographic inversion determines the group velocities of group angles of all layers of the VTI longitudinal wave vertical velocity model;
Scanning a VTI longitudinal wave vertical velocity model to obtain initial anisotropic parameters, and determining the group velocity of the VTI longitudinal wave vertical velocity model;
Searching the best fit of the group velocity of the VTI longitudinal wave vertical velocity model in the group velocity of each layer of group angle group of the VTI longitudinal wave vertical velocity model, and determining an intermediate anisotropic parameter;
Based on the intermediate anisotropic parameter, iterating ray tracing forward VTI longitudinal wave vertical velocity model until the error between the variable offset VSP first arrival travel time and the variable offset VSP actual measurement first arrival travel time of the VTI longitudinal wave vertical velocity model reaches a set value, and determining a final anisotropic parameter;
According to the measured first-arrival travel time of the variable offset VSP and the variable offset VSP first-arrival travel time and ray paths of the VTI longitudinal wave vertical velocity model, the tomographic inversion determines group velocities of group angles of all layers of group angles of the VTI longitudinal wave vertical velocity model, and the method comprises the following steps:
Grouping group angle angles of group velocities of the VTI longitudinal wave vertical velocity model, and determining group angle center angles of the group angle groupings;
Establishing a chromatographic equation according to the actual measurement of the variable offset VSP in the first-arrival travel and the ray path of the VTI longitudinal wave vertical velocity model;
Solving a chromatographic equation according to least square, and determining a group slowness variation corresponding to the central angle of each group angle;
And updating the group velocity of the group angle central angles of each layer of group angle grouping according to the group slowness variation corresponding to each group angle central angle.
2. The method of claim 1, wherein building the VTI longitudinal wave vertical velocity model from the zero offset VSP first arrival comprises:
determining a vertical single pass according to the first arrival of the zero offset VSP;
And determining the vertical velocity of the VTI longitudinal wave according to the vertical single pass, and establishing a VTI longitudinal wave vertical velocity model.
3. The method of claim 2, wherein the determination of the vertical single pass is performed by:
Where H i is the ith detector depth, t i is the ith first arrival, offfset is the distance of zero offset VSP shot from the wellhead, and t vi is the ith vertical single pass.
4. The method of claim 2, wherein the VTI longitudinal wave vertical velocity is determined as follows:
VP0,i＝(Hi-Hi-1)/(tvi-tvi-1)
Where H i-1 is the i-1 th detector depth, H i is the i-1 th detector depth, t vi-1 is the vertical single pass of the i-1 th detector, t vi is the vertical single pass of the i-th detector, and V P0,i is the VTI longitudinal wave vertical velocity of the i-th layer.
5. The method of claim 1, wherein ray tracing a forward VTI longitudinal wave vertical velocity model, determining a variable offset VSP first arrival trip time and ray path of the VTI longitudinal wave vertical velocity model, comprising:
Setting an initial phase angle of a VTI longitudinal wave vertical velocity model;
determining an initial phase velocity, an initial group velocity and an initial group angle according to the initial phase angle;
propagating the rays along the initial group angle direction, and calculating the intersection point of the rays and the interface;
performing transmission processing by Snell law at the intersection point of the interface, and calculating a transmission phase angle;
Based on the projection phase angle, iterating the initial phase angle layer by layer until the rays reach the well track, and determining the ray paths and the iterative group velocity;
And determining the variable offset VSP first arrival travel time of the VTI longitudinal wave vertical velocity model according to the ray path and the iterative group velocity.
6. The method of claim 5, wherein the initial phase velocity is determined as follows:
VP(θ)＝VP0(1+δsin2θcos2θ+εsin4θ)
Where θ is the initial phase angle, ε, δ are the VTI media anisotropy parameters, V P0 is the VTI longitudinal wave vertical velocity, and V P (θ) is the initial phase velocity of the longitudinal wave corresponding to the initial phase angle θ.
7. The method of claim 6, wherein the initial group velocity is determined as follows:
where θ is the initial phase angle, φ is the initial group angle, V P (θ) is the initial phase velocity, and V g (φ) is the initial group velocity.
8. The method of claim 7, wherein the initial group angle is determined as follows:
where θ is the initial phase angle, φ is the initial group angle, V P (θ) is the initial phase velocity, and V g (φ) is the initial group velocity.
9. The method of claim 7 wherein the variable offset VSP of the VTI longitudinal wave vertical velocity model is determined as follows:
Where n is the number of ray path segments, l i is the ith ray segment traced by the ray path, V gi is the group velocity corresponding to the ith ray segment, and T tra is the first arrival trip corresponding to the ray path.
10. The method of claim 1, wherein grouping group angle angles is performed as follows:
φci-Δφ<φi≤φci+Δφ
Where φ i is the ith group angle, φ ci is the group angle center angle of the ith group, Δφ is the grouping range.
11. The method of claim 1, wherein the chromatographic equation is established as follows:
ΔT＝Ttra-TVSP
LM×N·ΔSN×1＝ΔTM×1
Wherein L is the path of the ray path in each layer, delta S is the group slowness variation corresponding to the central angle of each group angle, M is the number of ray paths, N is the number of group angle groups, and T tra is the variable offset VSP of the VTI longitudinal wave vertical velocity model when traveling first; t VSP is the time of the actual measurement of the variable offset VSP first arrival travel; delta T is the error between when the variable offset VSP of the VTI longitudinal wave vertical velocity model first-arrival travel and when the variable offset VSP actually measures first-arrival travel.
12. The method of claim 1, wherein the group velocity of the group angle center angle of each layer group angle group is updated as follows:
Wherein phi ci is the group angle center angle of the i-th group, deltaS i is the group slowness variation corresponding to the group angle center angle of the i-th group, Group velocity, which is the group angle center angle of the i-th group before update,/>Is the updated group velocity of the group angle center angle of the i-th group.
13. The method of claim 1 wherein scanning the VTI longitudinal wave vertical velocity model to obtain initial anisotropic parameters and determining the VTI longitudinal wave vertical velocity model group velocity comprises:
Setting a scanning range and a scanning step length, and scanning a VTI longitudinal wave vertical velocity model to obtain initial anisotropic parameters;
And determining the group velocity of the VTI longitudinal wave vertical velocity model according to the initial anisotropic parameter and the VTI longitudinal wave vertical velocity model.
14. The method of claim 13, wherein the scan range and scan step size are set as follows:
εk＝εmin+(k-1)Δε,ε∈[εmin,εmax],k∈[1,(εmax-εmin)/Δε+1]
δl＝δmin+(l-1)Δδ,δ∈[δmin,δmax],l∈[1,(δmax-δmin)/Δδ+1]
Wherein epsilon min、εmax and delta epsilon are respectively a scanning minimum value, a scanning maximum value and a scanning step length of epsilon, delta min、δmax and delta are respectively a scanning minimum value, a scanning maximum value and a scanning step length of delta, k and l are the number of cycles, and epsilon and delta are the anisotropic parameters of the VTI medium.
15. The method of claim 14 wherein the VTI longitudinal wave vertical velocity model group velocities are determined as follows:
Wherein, θ ci is the phase angle corresponding to the group angle φ ci, V P,kl(θci) is the phase velocity with the anisotropy parameter ε k、δl and the phase angle θ ci, and V g,kl(φci) is the VTI longitudinal wave vertical velocity model group velocity with the anisotropy parameter ε k、δl and the group angle φ ci.
16. The method of claim 1 wherein finding a best fit of the VTI longitudinal wave vertical velocity model group velocities in the VTI longitudinal wave vertical velocity model layer angular packet group velocities, determining the intermediate anisotropy parameter comprises:
Calculating errors between the group velocities of the VTI longitudinal wave vertical velocity model and the group velocities of the angle groups of each layer of the VTI longitudinal wave vertical velocity model;
searching the minimum value of the error, and determining the minimum value as the best fitting group velocity of the VTI longitudinal wave vertical velocity model group velocity in the group angular grouping group velocity of each layer of the VTI longitudinal wave vertical velocity model;
And determining the anisotropic parameter corresponding to the best fit group velocity as an intermediate anisotropic parameter.
17. The method of claim 16, wherein the error comprises: standard deviation;
The standard deviation between the group velocity of the VTI longitudinal wave vertical velocity model and the group velocity of each layer group angle group of the VTI longitudinal wave vertical velocity model is calculated as follows:
Wherein, Group velocity with a group angle phi ci of the VTI vertical velocity model, V g,kl(φci) is group velocity with an anisotropy parameter epsilon k、δl and a group angle phi ci, and V std,kl is standard deviation of group velocity with an anisotropy parameter epsilon k、δl.
18. A variable offset VSP first arrival inversion VTI anisotropic parameter apparatus, comprising:
the VTI longitudinal wave vertical velocity model building module is used for building a VTI longitudinal wave vertical velocity model according to the zero offset VSP first arrival;
The VTI model first-arrival travel time and ray path determining module is used for ray tracing the forward VTI longitudinal wave vertical velocity model and determining the variable offset VSP first-arrival travel time and ray path of the VTI longitudinal wave vertical velocity model;
The chromatographic inversion module is used for determining group velocities of group angles of all layers of angles of the VTI longitudinal wave vertical velocity model according to the actual measurement of the variable offset VSP when the VTI longitudinal wave vertical velocity model arrives first, the variable offset VSP when the VTI longitudinal wave vertical velocity model arrives first and the ray path;
the VTI longitudinal wave vertical velocity model group velocity determining module is used for scanning the VTI longitudinal wave vertical velocity model to obtain initial anisotropic parameters and determining the VTI longitudinal wave vertical velocity model group velocity;
The middle anisotropic parameter determining module is used for searching the best fit of the VTI longitudinal wave vertical velocity model group velocity in the group angular group velocity of each layer group angle of the VTI longitudinal wave vertical velocity model and determining the middle anisotropic parameter;
The final anisotropic parameter determining module is used for iteratively ray tracing the forward VTI longitudinal wave vertical velocity model based on the intermediate anisotropic parameter until the error between the variable offset VSP of the VTI longitudinal wave vertical velocity model and the actual measurement of the variable offset VSP reaches a set value during first arrival travel, and determining the final anisotropic parameter;
the chromatographic inversion module is specifically used for:
According to the measured first-arrival travel time of the variable offset VSP and the variable offset VSP first-arrival travel time and ray paths of the VTI longitudinal wave vertical velocity model, the tomographic inversion determines group velocities of group angles of all layers of group angles of the VTI longitudinal wave vertical velocity model, and the method comprises the following steps:
Grouping group angle angles of group velocities of the VTI longitudinal wave vertical velocity model, and determining group angle center angles of the group angle groupings;
Establishing a chromatographic equation according to the actual measurement of the variable offset VSP in the first-arrival travel and the ray path of the VTI longitudinal wave vertical velocity model;
Solving a chromatographic equation according to least square, and determining a group slowness variation corresponding to the central angle of each group angle;
And updating the group velocity of the group angle central angles of each layer of group angle grouping according to the group slowness variation corresponding to each group angle central angle.
19. A computer device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, the processor implementing the variable offset VSP first-arrival inversion VTI anisotropic parameter method of any of claims 1 to 17 when the computer program is executed.
20. A computer readable storage medium storing a computer program which when executed by a processor implements the variable offset VSP first arrival inversion VTI anisotropic parameter method of any of claims 1 to 17.
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Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102213769A (en) * 2010-04-07 2011-10-12 中国石油天然气集团公司 Method for determining anisotropic parameters by utilizing data of three-dimensional VSP (Vertical Seismic Profile)
CN102759746A (en) * 2011-04-28 2012-10-31 中国石油天然气集团公司 Method for inverting anisotropy parameters using variable offset vertical seismic profile data
CN103149588A (en) * 2013-02-20 2013-06-12 中国石油天然气股份有限公司 Method and system for calculating VTI anisotropic parameters by using well seismic calibration
CN105093292A (en) * 2014-05-14 2015-11-25 中国石油天然气股份有限公司 Data processing method and device for seismic imaging
CN107918144A (en) * 2016-10-09 2018-04-17 中国石油化工股份有限公司 Anisotropic medium preliminary wave ray-tracing procedure and system
CN109655889A (en) * 2017-10-11 2019-04-19 中国石油化工股份有限公司 A kind of anisotropic parameters joint inversion method and system
CN110208854A (en) * 2019-06-28 2019-09-06 中国地质调查局沈阳地质调查中心 The acquisition methods of equivalent anisotropic parameters in a kind of VTI medium

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20100135115A1 (en) * 2008-12-03 2010-06-03 Chevron U.S.A. Inc. Multiple anisotropic parameter inversion for a tti earth model
BR112015023845A2 (en) * 2013-04-02 2017-07-18 Halliburton Energy Services Inc anisotropy analysis using direct arrivals and reflected in seismic survey data

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102213769A (en) * 2010-04-07 2011-10-12 中国石油天然气集团公司 Method for determining anisotropic parameters by utilizing data of three-dimensional VSP (Vertical Seismic Profile)
CN102759746A (en) * 2011-04-28 2012-10-31 中国石油天然气集团公司 Method for inverting anisotropy parameters using variable offset vertical seismic profile data
CN103149588A (en) * 2013-02-20 2013-06-12 中国石油天然气股份有限公司 Method and system for calculating VTI anisotropic parameters by using well seismic calibration
CN105093292A (en) * 2014-05-14 2015-11-25 中国石油天然气股份有限公司 Data processing method and device for seismic imaging
CN107918144A (en) * 2016-10-09 2018-04-17 中国石油化工股份有限公司 Anisotropic medium preliminary wave ray-tracing procedure and system
CN109655889A (en) * 2017-10-11 2019-04-19 中国石油化工股份有限公司 A kind of anisotropic parameters joint inversion method and system
CN110208854A (en) * 2019-06-28 2019-09-06 中国地质调查局沈阳地质调查中心 The acquisition methods of equivalent anisotropic parameters in a kind of VTI medium

Non-Patent Citations (4)

* Cited by examiner, † Cited by third party
Title
Li Jian-Guo 等.Traveltime tomography and prestack depth migration for vertical seismic profiling of an angle-domain walkaway on a complex surface.APPLIED GEOPHYSICS.2019,第16卷(第03期),第358-366页. *
VTI介质试射射线追踪;李建国 等;石油地球物理勘探;第45卷(第04期);第491-496页 *
Walkaway VSP井旁各向异性速度模型反演方法;侯爱源 等;石油地球物理勘探;第51卷(第02期);第301-305页 *
多测线变偏移距VSP地震各向异性反演;田鑫 等;地震学报;第37卷(第02期);第266-277页 *

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