Vertical seismic profile reflection point position determination method and system, and medium

Abstract

The invention provides a vertical seismic section reflection point position determination method and system and a medium, and belongs to the field of in-well seismic exploration. The method comprises the following steps: respectively acquiring vertical incidence time and root-mean-square velocity from an excitation point to the depth of a reflection point and from a receiving point to the depth of the reflection point according to input parameters, and finally acquiring the position of the reflection point according to the vertical incidence time and the root-mean-square velocity. Aiming at the problems that ray tracing efficiency is low and errors are large when a homogeneous medium is adopted in the prior art when the positions of the reflection points are calculated in VSP collection design, the invention provides a layer-to-layer medium-based high-precision quick calculation method for the reflection points, and the method has quick calculation efficiency and calculation precision equivalent to that of ray tracing.

Description

Technical Field

[0001] The invention belongs to the field of borehole seismic exploration, and in particular relates to a method, system and medium for determining the position of a reflection point of a vertical seismic profile. Background Art

[0002] The in-well VSP has the characteristics of high signal-to-noise ratio, high resolution and well-ground bridge due to its in-well reception, and has important applications in the field of seismic exploration.

[0003] VSP acquisition design is the premise to ensure the exploration effect, and the calculation of the reflection point position is a key step in the acquisition design, which involves the calculation of parameters such as coverage times, imaging range and stretching rate. Existing technologies mainly calculate the reflection point position through ray tracing or uniform medium model calculation formula. Among them, ray tracing is a high-precision calculation method, which fully considers the velocity change of the medium. However, this method is to constantly adjust the ray path by adopting a certain strategy or rule, gradually approaching the real ray path, so the calculation efficiency is low (especially in large models or with more shot checkpoints); another method is to simplify the model into a uniform medium, and the underground medium velocity adopts the average velocity. In this case, the reflection point position can be quickly calculated by using geometric relationships. The calculation result is independent of the medium velocity, only the shot checkpoint position and the reflection point depth. Since the medium velocity is ignored, the calculation accuracy is quite different from the actual result. Summary of the invention

[0004] The purpose of the present invention is to solve the above-mentioned problems existing in the prior art and to provide a method, system and medium for determining the position of reflection points in a vertical seismic profile.

[0005] One of the purposes of the present invention is to provide a method for determining the position of reflection points in a vertical seismic profile.

[0006] A second object of the present invention is to provide a system for determining the position of reflection points in a vertical seismic profile.

[0007] A third object of the present invention is to provide a computer-readable storage medium.

[0008] The present invention is achieved through the following technical solutions:

[0009] The first aspect of the present invention provides a method for determining the position of a reflection point in a vertical seismic profile, which obtains the vertical incidence time and root mean square velocity from the excitation point to the depth of the reflection point and from the receiving point to the depth of the reflection point according to the input parameters, and finally obtains the reflection point position according to the vertical incidence time and the root mean square velocity.

[0010] A further improvement of the present invention is:

[0011] The method comprises the following steps:

[0012] S10, input parameters;

[0013] S20, obtaining the vertical incident time from the excitation point to the reflection point depth;

[0014] S30, obtaining the root mean square velocity at the depth from the excitation point to the reflection point;

[0015] S40, obtaining the vertical incidence time from the receiving point to the depth of the reflection point;

[0016] S50, obtaining the root mean square velocity at the depth from the receiving point to the reflection point;

[0017] S60: Obtain the reflection point position.

[0018] A further improvement of the present invention is:

[0019] The input parameters in step S10 specifically include:

[0020] Input model parameters (h i ,v i ), i = 1, 2...N, N is the number of model layers, h i Indicates layer depth, v i Indicates layer velocity;

[0021] Enter the excitation point position x s , receiving point position x g ;

[0022] Enter the depth of the target reflection point h r , the excitation point depth h s and the receiving point depth h g .

[0023] A further improvement of the present invention is:

[0024] The step S20 of obtaining the vertical incident time from the excitation point to the reflection point depth includes:

[0025] Depth from the excitation point h s The depth from the layer to the reflection point h r The layer where the ray is located, calculate the vertical propagation distance s of each layer si , where i = 1, 2...N, N is the number of layers the ray passes through;

[0026] Calculate the vertical travel time t of each layer layer by layer si =s si / v i , where i = 1, 2...N, N is the number of layers the ray passes through, v i Indicates the layer velocity of the i-th layer that the ray passes through;

[0027] Formula (1) is used to calculate the vertical incident time t from the excitation point to the depth of the reflection point 0sr :

[0028]

[0029] A further improvement of the present invention is:

[0030] The root mean square velocity at the depth from the excitation point to the reflection point is obtained in step S30, specifically:

[0031] Formula (2) is used to calculate the root mean square velocity v at the depth from the excitation point to the reflection point sr :

[0032]

[0033] A further improvement of the present invention is:

[0034] The step S40 calculates the vertical incidence time from the receiving point to the depth of the reflection point, and the specific operations include:

[0035] Depth from receiving point h g The depth from the layer to the reflection point h r The layer where the ray is located, calculate the vertical propagation distance s of each layer gi , where i = 1, 2...N, N is the number of layers the ray passes through;

[0036] Calculate the vertical travel time t of each layer layer by layer gi =s gi / v i , where i = 1, 2...N, N is the number of layers the ray passes through, v i Indicates the layer velocity of the i-th layer that the ray passes through;

[0037] Formula (3) is used to calculate the vertical incidence time t from the receiving point to the depth of the reflection point 0gr :

[0038]

[0039] A further improvement of the present invention is:

[0040] In step S50, the root mean square velocity at the depth from the receiving point to the reflection point is obtained, specifically:

[0041] Formula (4) is used to calculate the root mean square velocity v at the depth from the receiving point to the reflection point gr :

[0042]

[0043] A further improvement of the present invention is:

[0044] The reflection point position is obtained in S60, specifically:

[0045] The reflection point position is calculated using formula (5):

[0046]

[0047] A second aspect of the present invention provides a system for determining a reflection point position of a vertical seismic profile, comprising:

[0048] Input module, used to input parameters;

[0049] A first acquisition module is used to acquire the vertical incident time at the depth from the excitation point to the reflection point;

[0050] The second acquisition module is used to obtain the root mean square velocity at the depth from the excitation point to the reflection point;

[0051] The third acquisition module is used to obtain the vertical incidence time at the depth from the receiving point to the reflection point;

[0052] A fourth acquisition module is used to acquire the root mean square velocity at the depth from the receiving point to the reflection point;

[0053] The fifth acquisition module is used to acquire the position of the reflection point.

[0054] According to a third aspect of the present invention, a computer-readable medium is provided, wherein the computer-readable storage medium stores at least one computer-executable program, and when the at least one program is executed by the computer, the computer executes the steps in the method for determining the position of reflection points in a vertical seismic profile as described above.

[0055] Compared with the prior art, the present invention has the following beneficial effects:

[0056] In order to solve the problems of low efficiency of ray tracing and large error of uniform medium when calculating the reflection point position in VSP acquisition design, the present invention proposes a high-precision and fast calculation method of reflection points based on layer-transferred media, which has both fast calculation efficiency and calculation accuracy comparable to ray tracing. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 It is a flow chart of a method for determining the position of a reflection point of a vertical seismic profile according to the present invention;

[0058] Figure 2 It is a schematic diagram of the principle of the method of the present invention;

[0059] Figure 3 is a distribution diagram of reflection point positions calculated using a uniform medium method in an embodiment;

[0060] Figure 4 is a distribution diagram of reflection point positions calculated using the method of the present invention in an embodiment;

[0061] Figure 5 3 is a distribution diagram of reflection point positions calculated using the ray tracing method in the embodiment. DETAILED DESCRIPTION

[0062] The present invention is further described in detail below in conjunction with the accompanying drawings:

[0063] The present invention provides a method for determining the position of a reflection point in a vertical seismic profile. According to input parameters, the vertical incidence time and the root mean square velocity from an excitation point to the depth of a reflection point and from a receiving point to the depth of a reflection point are determined respectively. Finally, the position of the reflection point is determined according to the vertical incidence time and the root mean square velocity.

[0064] [Example 1]

[0065] like Figure 1 and Figure 2 As shown, an embodiment of the present invention provides a method for determining the position of a reflection point of a vertical seismic profile, and the specific steps include:

[0066] S10, input parameters;

[0067] Input model parameters (h i ,v i ), i = 1, 2...N, N is the number of model layers, h i Indicates layer depth, v i Indicates layer velocity;

[0068] Enter the excitation point position x s , receiving point position x g ;

[0069] Enter the depth of the target reflection point h r , the excitation point depth h s and the receiving point depth h g .

[0070] S20, obtaining the vertical incident time from the excitation point to the reflection point depth;

[0071] Specific operations include:

[0072] Depth from the excitation point h s The depth from the layer to the reflection point h r The layer where the ray is located, calculate the vertical propagation distance s of each layer si , where i = 1, 2...N, N is the number of layers the ray passes through;

[0073] Calculate the vertical travel time t of each layer layer by layer si =s si / vi , where i = 1, 2...N, N is the number of layers the ray passes through, v i Indicates the layer velocity of the i-th layer that the ray passes through;

[0074] Formula (1) is used to calculate the vertical incident time t from the excitation point to the depth of the reflection point 0sr :

[0075]

[0076] S30, obtaining the root mean square velocity at the depth from the excitation point to the reflection point;

[0077] Specific operations include:

[0078] Formula (2) is used to calculate the root mean square velocity v at the depth from the excitation point to the reflection point sr :

[0079]

[0080] S40, obtaining the vertical incidence time from the receiving point to the depth of the reflection point;

[0081] Specific operations include:

[0082] Depth from receiving point h g The depth from the layer to the reflection point h r The layer where the ray is located, calculate the vertical propagation distance s of each layer gi , where i = 1, 2...N, N is the number of layers the ray passes through;

[0083] Calculate the vertical travel time t of each layer layer by layer gi =s gi / v i , where i = 1, 2...N, N is the number of layers the ray passes through, v i Indicates the layer velocity of the i-th layer that the ray passes through;

[0084] Formula (3) is used to calculate the vertical incidence time t from the receiving point to the depth of the reflection point 0gr :

[0085]

[0086] S50, obtaining the root mean square velocity at the depth from the receiving point to the reflection point;

[0087] Specific operations include:

[0088] Formula (4) is used to calculate the root mean square velocity v at the depth from the receiving point to the reflection point g :

[0089]

[0090] S60, obtaining the reflection point position and outputting it.

[0091] Specific operations include:

[0092] Formula (5) is used to calculate the reflection point position, specifically:

[0093]

[0094] Table 1 Example model parameters, including layer depth and layer velocity.

[0095] Table 1

[0096] Serial number 1 2 3 4 5 6 7 8 9 10 11 Layer depth (m) 0 1982 3260 3845 4445 6225 7420 8110 9210 10127 10950 Layer velocity (m / s) 1953 1953 2819 3803 4203 4604 4806 5770 6453 6714 5789

[0097] Figures 3 to 5 In the embodiment model, the observation system parameters are selected as follows: fixed excitation point depth h s At 0 meters, the horizontal position x s From 0 to 4000 meters (1 meter interval); fixed receiving point horizontal position x g At 0 m, depth h g From 0 to 4000 meters (1 meter interval). Using the uniform medium method ( Figure 3 ), the method of the present invention ( Figure 4 ) and ray tracing methods ( Figure 5 ) calculation, the target layer depth is h r is the reflection point x at 4000 meters r Location distribution map, the horizontal axis is x s , the vertical axis is h g , the color scale in the figure indicates the corresponding reflection point position x r Size, from Figures 3 to 5 It can be seen that the reflection point x calculated by the method of the present invention and the ray tracing method r The position distribution is highly consistent, and the calculation results of the uniform medium method are significantly different from those of the two methods (the positions indicated by the arrows), indicating that the method of the present invention is comparable to the ray tracing method in terms of accuracy. In addition, in terms of computational efficiency, the ray tracing method is 5 to 8 times more time-consuming than the method of the present invention, indicating that the computational efficiency of the present method is also higher.

[0098] [Example 2]

[0099] An embodiment of the present invention provides a system for determining a reflection point position of a vertical seismic profile, comprising:

[0100] The input module is used to input parameters and performs the following operations:

[0101] Input model parameters (h i ,vi ), i = 1, 2...N, N is the number of model layers, h i Indicates layer depth, v i Indicates layer velocity;

[0102] Enter the excitation point position x s , receiving point position x g ;

[0103] Enter the depth of the target reflection point h r , the excitation point depth h s and the receiving point depth h g .

[0104] The first acquisition module is used to obtain the vertical incident time at the depth from the excitation point to the reflection point, and specifically performs the following operations:

[0105] Depth from the excitation point h s The depth from the layer to the reflection point h r The layer where the ray is located, calculate the vertical propagation distance s of each layer si , where i = 1, 2...N, N is the number of layers the ray passes through;

[0106] Calculate the vertical travel time t of each layer layer by layer si =s si / v i , where i = 1, 2...N, N is the number of layers the ray passes through, v i Indicates the layer velocity of the i-th layer that the ray passes through;

[0107] Formula (1) is used to calculate the vertical incident time t from the excitation point to the depth of the reflection point 0sr :

[0108]

[0109] The second acquisition module is used to obtain the root mean square velocity at the depth from the excitation point to the reflection point, and specifically performs the following operations:

[0110] Formula (2) is used to calculate the root mean square velocity v at the depth from the excitation point to the reflection point sr :

[0111]

[0112] The third acquisition module is used to obtain the vertical incidence time at the depth from the receiving point to the reflection point, and specifically performs the following operations:

[0113] Depth from receiving point h g The depth from the layer to the reflection point h r The layer where the ray is located, calculate the vertical propagation distance s of each layer gi, where i = 1, 2...N, N is the number of layers the ray passes through;

[0114] Calculate the vertical travel time t of each layer layer by layer gi =s gi / v i , where i = 1, 2...N, N is the number of layers the ray passes through, v i Indicates the layer velocity of the i-th layer that the ray passes through;

[0115] Formula (3) is used to calculate the vertical incidence time t from the receiving point to the depth of the reflection point 0gr :

[0116]

[0117] The fourth acquisition module is used to obtain the root mean square velocity at the depth from the receiving point to the reflection point, and specifically performs the following operations:

[0118] Formula (4) is used to calculate the root mean square velocity v at the depth from the receiving point to the reflection point g :

[0119]

[0120] The fifth acquisition module is used to obtain the position of the reflection point, and specifically performs the following operations:

[0121] Formula (5) is used to calculate the reflection point position, specifically:

[0122]

[0123] [Example 3]

[0124] An embodiment of the present invention provides a computer-readable medium, which stores at least one computer-executable program. When the at least one program is executed by the computer, the computer executes the steps in the method for determining the position of reflection points in a vertical seismic profile as described in Example 1.

[0125] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the program can be stored in a non-volatile computer-readable storage medium. When the program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. As an illustration and not limitation, RAM is available in many forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

[0126] The above technical solution is only one implementation mode of the present invention. For those skilled in the art, it is easy to make various types of improvements or modifications based on the principles disclosed in the present invention, and it is not limited to the technical solution described in the above specific embodiments of the present invention. Therefore, the above description is only preferred and does not have a restrictive meaning.

Claims

1. A method for determining the position of a reflection point in a vertical seismic profile, characterized in that: According to the input parameters, the vertical incidence time and root mean square velocity from the excitation point to the depth of the reflection point and from the receiving point to the depth of the reflection point are obtained respectively, and finally the reflection point position is obtained according to the vertical incidence time and the root mean square velocity.

2. The method for determining the position of a reflection point in a vertical seismic profile according to claim 1, characterized in that: The method comprises the following steps: S10, input parameters; S20, obtaining the vertical incident time from the excitation point to the reflection point depth; S30, obtaining the root mean square velocity at the depth from the excitation point to the reflection point; S40, obtaining the vertical incidence time from the receiving point to the depth of the reflection point; S50, obtaining the root mean square velocity at the depth from the receiving point to the reflection point; S60: Obtain the reflection point position.

3. The method for determining the position of a reflection point in a vertical seismic profile according to claim 2, characterized in that: The input parameters in step S10 specifically include: Input model parameters (h i ,v i ), i = 1, 2...N, N is the number of model layers, h i Indicates layer depth, v i Indicates layer velocity; Enter the excitation point position x s , receiving point position x g ; Enter the depth of the target reflection point h r , the excitation point depth h s and the receiving point depth h g .

4. The method for determining the position of a reflection point in a vertical seismic profile according to claim 3, characterized in that: The step S20 of obtaining the vertical incident time from the excitation point to the reflection point depth includes: Depth from the excitation point h s The depth from the layer to the reflection point is h r The layer where the ray is located, calculate the vertical propagation distance s of each layer si , where i = 1, 2...N, N is the number of layers the ray passes through; Calculate the vertical travel time t of each layer layer by layer si =s si / v i , where i = 1, 2...N, N is the number of layers the ray passes through, v i Indicates the layer velocity of the i-th layer that the ray passes through; Formula (1) is used to calculate the vertical incident time t from the excitation point to the depth of the reflection point 0sr :

5. The method for determining the position of a reflection point in a vertical seismic profile according to claim 4, characterized in that: The root mean square velocity at the depth from the excitation point to the reflection point is obtained in step S30, specifically: Formula (2) is used to calculate the root mean square velocity v at the depth from the excitation point to the reflection point sr :

6. The method for determining the position of a reflection point in a vertical seismic profile according to claim 5, characterized in that: The step S40 calculates the vertical incidence time from the receiving point to the depth of the reflection point, and the specific operations include: Depth from receiving point h g The depth from the layer to the reflection point is h r The layer where the ray is located, calculate the vertical propagation distance s of each layer gi , where i = 1, 2...N, N is the number of layers the ray passes through; Calculate the vertical travel time t of each layer layer by layer gi =s gi / v i , where i = 1, 2...N, N is the number of layers the ray passes through, v i Indicates the layer velocity of the i-th layer that the ray passes through; Formula (3) is used to calculate the vertical incidence time t from the receiving point to the depth of the reflection point 0gr :

7. The method for determining the position of a reflection point in a vertical seismic profile according to claim 6, characterized in that: The root mean square velocity at the depth from the receiving point to the reflection point is obtained in step S50, specifically: Formula (4) is used to calculate the root mean square velocity v at the depth from the receiving point to the reflection point gr :

8. The method for determining the position of a reflection point in a vertical seismic profile according to claim 7, characterized in that: The reflection point position is obtained in S60, specifically: The reflection point position is calculated using formula (5):

9. A vertical seismic profile reflection point location determination system, characterized in that: include: Input module, used to input parameters; A first acquisition module is used to acquire the vertical incident time at the depth from the excitation point to the reflection point; The second acquisition module is used to obtain the root mean square velocity at the depth from the excitation point to the reflection point; The third acquisition module is used to obtain the vertical incidence time at the depth from the receiving point to the reflection point; A fourth acquisition module is used to acquire the root mean square velocity at the depth from the receiving point to the reflection point; The fifth acquisition module is used to acquire the position of the reflection point.

10. A computer-readable medium, characterized in that The computer-readable storage medium stores at least one computer-executable program, and when the at least one program is executed by the computer, the computer executes the steps in the method for determining the position of a reflection point in a vertical seismic profile as described in any one of claims 1-8.

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