Micro-logging time-depth curve vertical continuation method and system based on refraction inversion

Abstract

The invention discloses a micro-logging time-depth curve vertical continuation method and a micro-logging time-depth curve vertical continuation system based on refraction inversion. The micro-logging time-depth curve vertical continuation method comprises the following steps of: solving surface layer delay time and refraction layer speed of a shot point or a detection point in all directions; on the basis of the surface layer delay time and the refracting layer speed of the shot point or the detection point, performing interpolation to obtain the surface layer delay time and the refracting layer speed of the micro-logging; and refraction inversion is carried out on the micro-logging point position, and micro-logging time-depth curve continuation is completed. According to the method, when the refraction layer intercept is solved in an omnibearing mode, only the offset, the first arrival time and the partition angle of the first arrival data of a large shot are taken as calculation parameters, the method is not affected by the anisotropy problem of seismic wave propagation, the first arrival gather of a single shot point or a detection point can be calculated, other data points do not need to be used in an associated mode under special conditions, and the calculation efficiency is greatly improved. The requirement on data quality is low, and practical application is facilitated; the continuation depth of the micro-logging time-depth curve is deduced and calculated based on a refracted wave time-distance curve formula, and the result is accurate and reliable.

Description

Technical Field

[0001] The invention belongs to the technical field of petroleum seismic exploration, and in particular relates to a method and system for vertical extension of a micro-well logging time-depth curve based on refraction inversion. Background Art

[0002] Micro-logging is the most reliable data basis for surface research, but in actual construction, micro-logging often fails to penetrate the high-speed top, making it difficult to play its due role in the establishment of surface structure models, and its help in surface structure research is limited. In addition, inaccurate surface structure models are of no practical help for subsequent static correction calculations, and ultimately affect seismic exploration data processing and imaging.

[0003] The relevant technologies to solve this problem at home and abroad mainly extend the micro-well logging through the classical interchange method (ABC method) or the omnidirectional interchange method (OABC). In the ABC method, A and B are the shot points, and C is the receiving point. The three points must be in a straight line, so the delay time T of point C is C equal:

[0004] T C =(T AC +T BC -T AB ) / 2

[0005] Among them, T AC is the propagation time of seismic waves between AC; T BC is the propagation time of seismic waves between BC; T AB is the propagation time of the seismic wave between AB.

[0006] Then, the extended calculation is completed based on the delay time of point C combined with the existing time-depth curve of micro-logging.

[0007] The OABC method is an upgraded method of ABC, which is to search for all pairs of gun points that meet the conditions of the ABC method in all directions around point C, calculate a delay time of point C for each gun point pair, and finally obtain the delay time of point C through statistics.

[0008] The existing ABC method requires that points A, B, and C must be on the same straight line. Only seismic data from two-dimensional straight line construction can meet the requirement. In order to cope with the increasing number of three-dimensional seismic construction data, the OABC method has been upgraded. Although points A, B, and C on the same straight line can be found in all directions, the shot points and detection points of three-dimensional construction have their own line distances and point distances. It is often difficult to find points A, B, and C that meet the requirements in all directions, and many micro-well points cannot complete the extension calculation. In addition, both the ABC method and the OABC method require a stable refraction layer and cannot have anisotropy problems, which makes these two methods impossible to use in areas with complex surface structures. Summary of the invention

[0009] In view of the above problems, the present invention discloses a method for vertical extension of micro-well logging time-depth curve based on refraction inversion, comprising:

[0010] Obtain the surface delay time and refraction layer velocity of the shot point or receiver point in all directions;

[0011] Based on the surface delay time and the refractive layer velocity of the shot point or the receiver point, interpolating to obtain the surface delay time and the refractive layer velocity of the micro-well logging;

[0012] Refraction inversion is performed on the micro-logging points to complete the extension of the micro-logging time-depth curve.

[0013] Furthermore, the surface delay of the shot point or the receiver point is determined by the following steps:

[0014] The first arrival data of the gun point or the receiver point are divided into several angle intervals in the plane coordinate system according to the point coordinates;

[0015] The first arrival data of the cannon in each angle interval is fitted by the least squares linear fitting formula to obtain the intercepts of all angle intervals;

[0016] Find the mean square error of the intercepts for all angle intervals;

[0017] Subtract the average value of all intercept times from the intercept time of each angle interval to obtain the corresponding intercept time difference. Compare the intercept time difference with the mean square error of the intercept time. If the intercept time difference is less than the mean square error of the intercept time, the corresponding intercept time is a qualified intercept time.

[0018] The average value of all qualified intercept times is calculated to obtain the final intercept time at the shot point or receiver point, that is, the surface delay time from the surface elevation to the high-speed top interface.

[0019] Furthermore, the refraction layer velocity of the shot point or the receiver point is determined by the following steps:

[0020] The first arrival data of the gun point or the receiver point are divided into several angle intervals in the plane coordinate system according to the point coordinates;

[0021] The first arrival data of the cannon in each angle interval are fitted by the least squares linear fitting formula to obtain the refraction layer velocity in all angle intervals;

[0022] Calculate the mean square error of the refraction layer velocity in all angle intervals;

[0023] After subtracting the average value of all refraction layer velocities from the refraction layer velocity in each angle interval, the corresponding refraction layer velocity difference is obtained, and the refraction layer velocity difference is compared with the mean square error of the refraction layer velocity. If the refraction layer velocity difference is less than the mean square error of the refraction layer velocity, the corresponding refraction layer velocity is a qualified refraction layer velocity;

[0024] The average value of all qualified refraction layer velocities is calculated to obtain the final refraction layer velocity at the shot point or receiver point.

[0025] Furthermore, the specific steps of interpolating the micro-well logging surface delay time and the refractive layer velocity based on the surface delay time and the refractive layer velocity of the shot point or the detection point are as follows:

[0026] With the micro-logging as the center of the circle, the radius distance is set, and the surface delay time or refraction layer velocity of the shot point and the receiver point within the micro-logging radius distance is used as the interpolation sample point;

[0027] The interpolation sample points are brought into the interpolation function of the inverse distance weighted interpolation to calculate the micro-logging surface delay time or the refraction layer velocity.

[0028] Furthermore, the radius distance ranges from 0 to 600 m.

[0029] Furthermore, the specific steps of performing refraction inversion on the micro-logging points and completing the extension of the micro-logging time-depth curve are as follows:

[0030] Assume that the interpretation results of the current depth of micro-well logging have n layers;

[0031] The thickness of each layer h of the micro-logging interpretation results i , speed V i , the speed V of the nth layer n and the refractive layer velocity V R Substituting into the extension layer thickness formula, h can be obtained n , that is, the thickness of the micro-logging extension layer.

[0032] Furthermore, the thickness formula of the extension layer is as follows:

[0033]

[0034] Among them, h n is the thickness of the nth layer; V n is the speed of the nth layer; θ nR is the incident angle of the ray entering the refractive layer R from the nth layer; t R When it is the two-way intercept; i is the thickness of the i-th layer, i=1,2,…,n; V i is the velocity of the i-th layer; θ iR is the incident angle of the ray entering the i-th layer from the i-1th layer.

[0035] The present invention also discloses a micro-well logging time-depth curve vertical extension system based on refraction inversion, comprising:

[0036] An obtaining unit is used to obtain the surface delay time and refraction layer velocity of a shot point or a receiver point in all directions;

[0037] An interpolation unit is used to interpolate the surface delay time and the refractive layer velocity of the micro-well logging based on the surface delay time and the refractive layer velocity of the shot point or the detection point;

[0038] The extension unit is used to perform refraction inversion on the micro-logging points to complete the extension of the micro-logging time-depth curve.

[0039] Furthermore, the interpolation unit is specifically used for:

[0040] With the micro-logging as the center of the circle, the radius distance is set, and the surface delay time or refraction layer velocity of the shot point and the receiver point within the micro-logging radius distance is used as the interpolation sample point;

[0041] The interpolation sample points are brought into the interpolation function of the inverse distance weighted interpolation to calculate the micro-logging surface delay time or the refraction layer velocity.

[0042] Furthermore, the extension unit is specifically used for:

[0043] Assume that the interpretation results of the current depth of micro-well logging have n layers;

[0044] The thickness of each layer h of the micro-logging interpretation results i , speed V i , the speed V of the nth layer n and the refractive layer velocity V R Substituting into the extension layer thickness formula, h can be obtained n , that is, the thickness of the micro-logging extension layer.

[0045] Compared with the prior art, the embodiments of the present invention have at least the following advantages: when the intercept of the refraction layer is obtained in all directions, the present invention only takes the offset distance, the first arrival time and the partition angle of the first arrival data of the cannon as calculation parameters, which is not affected by the anisotropy problem of seismic wave propagation, and the first arrival gather of a single shot point or detection point can be calculated, and no special conditions are required to associate and use other data points, and the requirements for data quality are low, which is convenient for practical application; the micro-logging time-depth curve is derived and calculated based on the formula of the refraction wave time-distance curve, which has a theoretical basis and the result is accurate and reliable; it has guiding significance for the establishment of surface structure model and surface structure research.

[0046] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0048] Figure 1 A schematic flow chart of a vertical extension method of a micro-well logging time-depth curve based on refraction inversion according to an embodiment of the present invention is shown;

[0049] Figure 2 A schematic diagram of multi-directional partitioning of a shot point or receiver point cannon first arrival gather according to an embodiment of the present invention is shown;

[0050] Figure 3 A schematic diagram of linear fitting of first arrival time-distance curves of cannons in different directions according to an embodiment of the present invention is shown;

[0051] Figure 4 A schematic diagram showing the micro-logging intercept obtained by interpolating the shot point or receiver point intercept according to an embodiment of the present invention is shown;

[0052] Figure 5 A schematic diagram of the extension result of the micro-well logging time-depth curve according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0053] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0054] Figure 1 FIG. 2 shows a flow chart of a vertical extension method of a micro-well logging time-depth curve based on refraction inversion according to an embodiment of the present invention. Figure 1 As shown, the present invention proposes a method for vertical extension of micro-well logging time-depth curve based on refraction inversion, comprising the following steps:

[0055] Step S101, obtaining the surface delay time and refraction layer velocity of the shot point or the receiver point in all directions.

[0056] In this step, the first arrival data of the shot point or the detection point are divided into a number of angle intervals in the plane coordinate system according to their point coordinates (the number of angle intervals can be set manually based on experience, and illustratively, it is divided into 22 angle intervals), such as Figure 2As shown, the first arrival data of the cannon in each angle interval are placed in the xt rectangular coordinate system where x is the offset and t is the time, as shown in Figure 3 As shown in the figure, the offset range of the first arrival of the cannon in the first refractive layer is obtained according to the observation. The first arrival data of the cannon in the range are substituted into the least squares linear fitting formula in the manner of x equals the offset distance and y equals the first arrival time t. If the number of fittings is 1, the linear formula can be finally obtained:

[0057] t=ax+b (1)

[0058] in:

[0059] x: offset;

[0060] t: time;

[0061] a: constant;

[0062] b: constant;

[0063] At this time, the reciprocal of a is the refraction layer velocity in the current angle interval. When the offset distance x is equal to 0, we can get:

[0064] t=b

[0065] At this time, b is the intercept obtained by the shot point or detection point in the current angle interval.

[0066] According to this method, the intercept time and refractive layer velocity of each angle interval are calculated in turn, and the calculated intercept time is substituted into the mean square error formula as the variable x:

[0067]

[0068] in:

[0069] σ: mean square error;

[0070] μ: mean value;

[0071] x: variable;

[0072] i: variable number;

[0073] n: number of variables;

[0074] x i : variable number i;

[0075] Obtain the mean square error of the intercept time, subtract the average of all intercept times from the intercept time of each angle interval, and obtain the intercept time difference d' of each angle interval, and compare it with the mean square error of the intercept time. When d' is less than the mean square error of the intercept time, the corresponding intercept time is regarded as the qualified intercept time, and the rest are unqualified intercept times. Take the average value of all qualified intercept times to obtain the final intercept time at the shot point or detection point, that is, the surface delay time from the surface elevation to the high-speed top interface (refractive layer interface). Similarly, substitute the refractive layer velocity of each angle interval into the mean square error formula, and finally obtain the refractive layer velocity at the shot point.

[0076] Although there are various anisotropy problems in complex surface structure areas, resulting in inconsistent refraction velocities of seismic waves from the same shot in different directions, their intercept time at time 0 should be consistent, and this time is the delay time from the surface to the high-speed top interface. The method for obtaining the intercept time of the refraction layer in all directions is based on this principle. First, the first arrival time-distance curve of the shot point or the detection point is linearly fitted in azimuth, and the intercept time at time 0 is calculated based on the time-distance curve. After the intercept time of each azimuth obtained is statistically averaged, the final intercept time of the shot point can be obtained, that is, the surface delay time from the surface elevation to the high-speed top interface (refractive layer interface), which provides the most important time parameter for the calculation of the micro-well logging extension depth.

[0077] Step S102, using the surface delay time and refractive layer velocity of the shot point or the receiver point, interpolating to obtain the micro-well logging surface delay time and refractive layer velocity.

[0078] In this step, the micro-logging is taken as the center of the circle, the radius distance is set, and the surface delay time of the shot points and the detection points around the micro-logging radius is searched as the interpolation sample points of the micro-logging surface delay time, such as Figure 4 As shown in the figure, S1 and S2 represent different shot points, U is micro-logging, T 0Z The micro-logging surface delay time is obtained by interpolating the surface delay time of the surrounding shot points or receiver points. The value of the radius distance can be given based on experience according to the characteristics of different regions. For example, the radius distance ranges from 0 to 600m. Preferably, the radius distance is 200m.

[0079] The interpolation method uses the inverse distance weighted interpolation method, and the formula is:

[0080] Suppose there are n points with plane coordinates (x i ,y i ), the value is z i , i=1,2,…,n, the interpolation function of inverse distance weighted interpolation is:

[0081]

[0082] in From (x,y) to (x i,y i ), i = 1, 2, …, n. p is a constant greater than 0, called the weighted power exponent.

[0083] in:

[0084] (x i ,y i ) is the plane coordinate of the i-th point;

[0085] i: the index of the i-th point, i = 1, 2, ..., n;

[0086] z i : The value of the i-th point;

[0087] d i :(x,y) point to (x i ,y i ) point horizontal distance;

[0088] p: a weighted power index greater than 0; p can be set according to actual conditions. For example, p can be set to 1.

[0089] When using this formula to interpolate the surface delay time of micro-logging, substitute the coordinates of the shot point and the receiver point into (x i ,y i ), the intercepts of the shot point and the receiver point are entered as z i , the coordinates of the micro-logging point are (x, y), then the surface delay time of the micro-logging can be calculated. Similarly, the refractive layer velocity of the shot point and the receiver point is substituted into the z in the formula i , the refractive layer velocity of micro-well logging can be calculated.

[0090] Step S103, using the refraction wave time-distance curve formula to perform refraction inversion of the micro-logging point, and complete the extension of the micro-logging time-depth curve.

[0091] In this step, assuming that the interpretation results of the current depth of the micro-well logging have n layers, the interpretation results of the micro-well logging are:

[0092] 1st layer speed, 1st layer thickness;

[0093] Layer 2 speed, layer 2 thickness;

[0094] …

[0095] The speed of the n-1th layer, the thickness of the n-1th layer;

[0096] The nth layer speed.

[0097] Among them, the n-1 layer has thickness, and the nth layer only has layer velocity, and it is not the refraction layer velocity. Therefore, the layer that needs to be extended is the nth layer. Since the velocity of the nth layer has been obtained through interpretation, it is only necessary to calculate the thickness of the nth layer and the velocity of the n+1th layer to complete the micro-well logging extension. The n+1th layer is the refraction layer, recorded as the R layer. The micro-well logging refraction layer velocity calculated above is the velocity of the R layer. Therefore, only the extended thickness is unknown, and its calculation formula can be derived from the refraction wave time-distance curve formula. The refraction wave time-distance curve formula is:

[0098]

[0099] in:

[0100] in:

[0101] t 双 : Two-way delay;

[0102] x: offset;

[0103] i: layer number;

[0104] n: number of layers (or the last layer number);

[0105] θ i : the incident angle of the i-th layer;

[0106] h i : the thickness of the i-th layer, i = 1, 2, …, n;

[0107] V i : The speed of the i-th layer;

[0108] V R : refractive layer velocity;

[0109] When the offset x=0:

[0110]

[0111] From this, it can be deduced that the thickness of the nth layer (the last layer) is:

[0112]

[0113] in,

[0114] t R : Two-way intercept time (i.e. two-way delay time when the offset is 0) 双 );

[0115] θ nR : The incident angle of the ray entering the refractive layer R from the nth layer;

[0116] hn : the thickness of the nth layer;

[0117] V n : The speed of the nth layer;

[0118] θ iR : The incident angle of the ray entering the i-1th layer from the i-1th layer.

[0119] The thickness of each layer h of the micro-logging interpretation results i , speed V i , the speed V of the nth layer n and the refractive layer velocity V R Substituting into the extension layer thickness formula, h can be obtained n , that is, the thickness of the micro-logging extension layer. The final micro-logging results have n+1 layers, and the complete interpretation results after extension are as follows:

[0120] 1st layer speed, 1st layer thickness;

[0121] Layer 2 speed, layer 2 thickness;

[0122] …

[0123] The speed of the n-1th layer, the thickness of the n-1th layer;

[0124] nth layer speed, nth layer thickness;

[0125] The speed of the n+1th layer.

[0126] By deriving the formula of the refraction wave time-distance curve, the formula of the micro-well logging extension layer thickness obtained has a theoretical basis, and the calculated micro-well logging time-depth curve extension result is accurate and reliable.

[0127] like Figure 5 As shown, the micro-logging time-depth curve is displayed in the rectangular coordinate system of depth time dt. In the figure, du is the micro-logging depth. According to the current well depth, only one layer of thickness h1 can be obtained through micro-logging interpretation.

[0128] h1=d1

[0129] After the time-depth curve is extended by the method of the present invention, the thickness h2 of the extended layer can be obtained.

[0130] h2=d2-d1

[0131] For areas where micro-logging cannot penetrate the high-speed top boundary, micro-logging through time-depth curve extension can explain reasonable surface results.

[0132] In the present invention, the intercept time of the refraction layer is first obtained by using a comprehensive method to obtain the intercept time of the shot point and the detection point and the refraction layer velocity, and then the intercept time and the refraction layer velocity of the micro-logging point are obtained by using the inverse distance weighted interpolation method. The intercept time is the surface delay time from the surface elevation to the high-speed top interface (refractive layer interface). By deriving the formula of the refraction wave time-distance curve, the formula of the micro-logging extension layer thickness can be obtained, and the micro-logging time-depth curve extension calculation can be completed. The extended micro-logging can establish a reasonable surface structure model, which plays a guiding and restraining role in the subsequent static correction calculation and other work.

[0133] Based on the above-mentioned vertical extension method of micro-well logging time-depth curve based on refraction inversion, this embodiment proposes a vertical extension system of micro-well logging time-depth curve based on refraction inversion, including:

[0134] An obtaining unit is used to obtain the surface delay time and refraction layer velocity of a shot point or a receiver point in all directions;

[0135] An interpolation unit is used to interpolate the surface delay time and the refractive layer velocity of the micro-well logging based on the surface delay time and the refractive layer velocity of the shot point or the detection point;

[0136] The extension unit is used to perform refraction inversion on the micro-logging points to complete the extension of the micro-logging time-depth curve.

[0137] The interpolation unit is specifically used for:

[0138] With the micro-logging as the center of the circle, the radius distance is set, and the surface delay time or refraction layer velocity of the shot point and the receiver point within the micro-logging radius distance is used as the interpolation sample point;

[0139] The interpolation sample points are brought into the interpolation function of the inverse distance weighted interpolation to calculate the micro-logging surface delay time or the refraction layer velocity.

[0140] The extension unit is specifically used for:

[0141] Assume that the interpretation results of the current depth of micro-well logging have n layers;

[0142] The thickness of each layer h of the micro-logging interpretation results i , speed V i , the speed V of the nth layer n and the refractive layer velocity V R Substituting into the extension layer thickness formula, h can be obtained n , that is, the thickness of the micro-logging extension layer.

[0143] The vertical extension method of the micro-logging time-depth curve based on refraction inversion provided in the embodiment of the present invention can be specific hardware on the device or software or firmware installed on the device. The system provided in the embodiment of the present invention has the same implementation principle and technical effects as the aforementioned method embodiment. For the sake of brief description, the parts not mentioned in the system embodiment can refer to the corresponding contents in the aforementioned method embodiment. Technical personnel in the relevant field can clearly understand that for the convenience and simplicity of description, the specific working processes of the systems, devices and units described above can all refer to the corresponding processes in the aforementioned method embodiment, and will not be repeated here.

[0144] In the embodiments provided by the present invention, it should be understood that the disclosed devices and methods can be implemented in other ways. The device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some communication interfaces, and the indirect coupling or communication connection of devices or units can be electrical, mechanical or other forms.

[0145] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0146] In addition, each functional unit in the embodiment provided by the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0147] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc., which can store program codes.

[0148] It should be noted that similar numbers and letters represent similar items in the following figures. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description and are not to be understood as indicating or implying relative importance.

[0149] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent substitutions for some of the technical features therein; and these modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A vertical extension method of micro-well logging time-depth curve based on refraction inversion, characterized in that: include: Obtain the surface delay time and refraction layer velocity of the shot point or receiver point in all directions; Based on the surface delay time and the refractive layer velocity of the shot point or the receiver point, interpolating to obtain the micro-well logging surface delay time and the refractive layer velocity; Refraction inversion is performed on the micro-logging points to complete the extension of the micro-logging time-depth curve.

2. The vertical extension method of micro-well logging time-depth curve based on refraction inversion according to claim 1 is characterized in that: The surface delay of the shot point or receiver point is determined by the following steps: Divide the first arrival data of the shot point or the receiver point into several angle intervals according to the point coordinates in the plane coordinate system; The first arrival data of the cannon in each angle interval is fitted by the least squares linear fitting formula to obtain the intercepts of all angle intervals; Find the mean square error of the intercepts for all angle intervals; Subtract the average value of all intercept times from the intercept time of each angle interval to obtain the corresponding intercept time difference. Compare the intercept time difference with the mean square error of the intercept time. If the intercept time difference is less than the mean square error of the intercept time, the corresponding intercept time is a qualified intercept time. The average value of all qualified intercept times is calculated to obtain the final intercept time at the shot point or receiver point, that is, the surface delay time from the surface elevation to the high-speed top interface.

3. The vertical extension method of micro-well logging time-depth curve based on refraction inversion according to claim 1 is characterized in that: The refraction layer velocity of the shot point or the receiver point is determined by the following steps: Divide the first arrival data of the shot point or the receiver point into several angle intervals according to the point coordinates in the plane coordinate system; The first arrival data of the cannon in each angle interval are fitted by the least squares linear fitting formula to obtain the refraction layer velocity in all angle intervals; Calculate the mean square error of the refraction layer velocity in all angle intervals; After subtracting the average value of all refraction layer velocities from the refraction layer velocity in each angle interval, the corresponding refraction layer velocity difference is obtained, and the refraction layer velocity difference is compared with the mean square error of the refraction layer velocity. If the refraction layer velocity difference is less than the mean square error of the refraction layer velocity, the corresponding refraction layer velocity is a qualified refraction layer velocity; The average value of all qualified refraction layer velocities is calculated to obtain the final refraction layer velocity at the shot point or receiver point.

4. The vertical extension method of micro-well logging time-depth curve based on refraction inversion according to claim 1 is characterized in that: The specific steps of interpolating the surface delay time and the refractive layer velocity of the micro-well logging based on the surface delay time and the refractive layer velocity of the shot point or the receiver point are as follows: With the micro-logging as the center, set the radius distance, and use the surface delay time or refraction layer velocity of the shot point and the receiver point within the micro-logging radius distance as the interpolation sample point; The interpolation sample points are brought into the interpolation function of the inverse distance weighted interpolation to calculate the micro-logging surface delay time or the refraction layer velocity.

5. The vertical extension method of micro-well logging time-depth curve based on refraction inversion according to claim 4 is characterized in that: The radius distance ranges from 0 to 600 m.

6. The vertical extension method of micro-well logging time-depth curve based on refraction inversion according to claim 1 is characterized in that: The specific steps of performing refraction inversion on the micro-logging points and completing the extension of the micro-logging time-depth curve are as follows: Assume that the interpretation results of the current depth of micro-well logging have n layers; The thickness of each layer h of the micro-logging interpretation results i , speed V i , the speed V of the nth layer n and the refractive layer velocity V R Substituting into the extension layer thickness formula, h can be obtained n , that is, the thickness of the micro-logging extension layer.

7. The vertical extension method of micro-well logging time-depth curve based on refraction inversion according to claim 6 is characterized in that: The thickness formula of the extension layer is as follows: Among them, h n is the thickness of the nth layer; V n is the speed of the nth layer; θ nR is the incident angle of the ray entering the refractive layer R from the nth layer; t R When it is the two-way intercept; i is the thickness of the i-th layer, i = 1, 2, ..., n; V i is the velocity of the i-th layer; θ iR is the incident angle of the ray entering the i-th layer from the i-1th layer.

8. A vertical extension system of micro-well logging time-depth curve based on refraction inversion, characterized in that: include: An obtaining unit is used to obtain the surface delay time and refraction layer velocity of a shot point or a receiver point in all directions; An interpolation unit is used to interpolate the surface delay time and the refractive layer velocity of the micro-well logging based on the surface delay time and the refractive layer velocity of the shot point or the detection point; The extension unit is used to perform refraction inversion on the micro-logging points to complete the extension of the micro-logging time-depth curve.

9. The vertical extension system of micro-well logging time-depth curve based on refraction inversion according to claim 8 is characterized in that: The interpolation unit is specifically used for: With the micro-logging as the center, set the radius distance, and use the surface delay time or refraction layer velocity of the shot point and the receiver point within the micro-logging radius distance as the interpolation sample point; The interpolation sample points are brought into the interpolation function of the inverse distance weighted interpolation to calculate the micro-logging surface delay time or the refraction layer velocity.

10. The vertical extension system of micro-well logging time-depth curve based on refraction inversion according to claim 8, characterized in that: The extension unit is specifically used for: Assume that the interpretation results of the current depth of micro-well logging have n layers; The thickness of each layer h of the micro-logging interpretation results i , speed V i , the speed V of the nth layer n and the refractive layer velocity V R Substituting into the extension layer thickness formula, h can be obtained n , that is, the thickness of the micro-logging extension layer.

Images