A buried hill interior fine velocity modeling method, system, computer storage medium and device based on a reservoir model

Abstract

The application discloses a buried hill inside fine velocity modeling method based on an oil reservoir model, and comprises the following steps: small-scale fractures are extracted by extrapolating well logging scale fractures; seismic scale fractures and cracks are extracted; based on the small-scale fractures, the seismic scale fractures and cracks are taken as constraints to simulate the spatial distribution trend of the fractures, so that a fracture model of a work area is obtained; a fracture equivalent porosity model is established; a porosity and seismic velocity crossplot is established; the porosity and seismic velocity crossplot is corrected to obtain a fracture porosity and seismic velocity crossplot, and a fitting relationship between the fracture porosity and the seismic velocity is established; and the fracture equivalent porosity model is mapped into a velocity model of a buried hill fracture medium according to the fitting relationship between the fracture porosity and the seismic velocity. The application can effectively improve the precision and efficiency of velocity modeling of a buried hill inside fracture reservoir, and reduce the influence of subjective factors of a person when performing fracture velocity modeling by manual fracture delineation.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of seismic data acquisition, and in particular, is especially about a buried hill inside fine velocity modeling method, system, computer storage medium and equipment based on a reservoir model. BACKGROUND

[0002] In recent years, offshore buried hill exploration has made breakthroughs. The discovery of the Bohai 19-6 buried hill, the Huizhou 26-6 buried hill, and the Bohai 26-6 buried hill, which have a total of hundreds of millions of cubic meters of oil and gas reserves, has triggered a wave of offshore buried hill oil and gas exploration. The buried hills represented by Bohai 19-6 and Bohai 26-6 have their oil and gas mainly occurring in the fractured reservoirs in the buried hill interior.

[0003] Buried hill exploration usually requires seismic data acquisition in the buried hill work area. In order to better demonstrate the economy and effectiveness of the seismic acquisition observation system, a velocity model needs to be established for the work area, and the observation system needs to be analyzed and evaluated based on the established velocity model.

[0004] For fractured buried hills, the velocity model corresponding to the fractured media in the interior is usually described by manual methods and filled in by hand, which is low in efficiency, highly subjective, and prone to loss of detailed information, making it difficult to well represent the characteristics of the fractures in the buried hill interior. The above-mentioned manual method can still be used when establishing a two-dimensional velocity model, but when establishing a three-dimensional velocity model, the efficiency is very low and the difficulty is very great. SUMMARY

[0005] The present application aims to at least solve one of the technical problems existing in the prior art. To this end, the present application provides a buried hill interior fine velocity modeling method based on a reservoir model, which aims to map the fine velocity model of the buried hill interior by means of the fitting relationship between the porosity and the velocity on the well, through the buried hill interior fracture type reservoir model, thereby avoiding the problems of poor accuracy and low efficiency of manual buried hill interior velocity modeling.

[0006] To achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0007] In a first aspect, the present application provides a buried hill interior fine velocity modeling method based on a reservoir model, comprising the following steps:

[0008] Small-scale fractures formed by extrapolating wellbore logging scale fractures from logging imaging data;

[0009] Fractures and cracks of seismic scale extracted from post-stack seismic data;

[0010] Based on the small-scale fractures formed by extrapolating wellbore logging scale fractures from logging imaging data, the fractures and cracks of seismic scale are used as constraints to simulate the spatial distribution trend of the fractures, and a work area fracture model is obtained.

[0011] establishing a fracture equivalent porosity model based on the fracture porosity logging curve obtained from the fracture model and the logging interpretation;

[0012] establishing a porosity-seismic velocity crossplot based on the porosity and seismic velocity in the logging interpretation result data;

[0013] correcting the porosity-seismic velocity crossplot to obtain a fracture porosity-seismic velocity crossplot, and establishing a fitting relationship between the fracture porosity and the seismic velocity based on the fracture porosity-seismic velocity crossplot;

[0014] mapping the fracture equivalent porosity model to a velocity model of the buried-hill fractured medium according to the fitting relationship between the fracture porosity and the seismic velocity.

[0015] As preferred: the seismic-scale fractures and cracks are ant bodies formed by using Petrel software to perform ant tracking on post-stack seismic data.

[0016] As preferred: the "small-scale fractures formed by extrapolating the well-adjacent logging-scale fractures, taking the seismic-scale fractures and cracks as constraints, and performing fracture spatial distribution trend simulation to obtain a fracture model of the work area" specifically refers to:

[0017] introducing the small-scale fractures formed by extrapolating the well-adjacent logging-scale fractures into the Petrel software, taking the seismic-scale fractures and cracks as constraints, and performing fracture spatial distribution trend simulation by using the discrete fracture network modeling in the Petrel software to obtain a fracture model of the work area.

[0018] As preferred: the "establishing a fracture equivalent porosity model based on the fracture porosity logging curve obtained from the fracture model and the logging interpretation" specifically refers to:

[0019] introducing the fracture porosity logging curve and the fracture model of the work area into the Petrel software to establish a fracture equivalent porosity model.

[0020] As preferred: the "establishing a porosity-seismic velocity crossplot based on the porosity and seismic velocity in the logging interpretation result data" specifically refers to:

[0021] performing point projection on the porosity and seismic velocity in the logging interpretation result data to form a porosity-seismic velocity crossplot.

[0022] As preferred: the "correcting the porosity-seismic velocity crossplot to obtain a fracture porosity-seismic velocity crossplot, and establishing a fitting relationship between the fracture porosity and the seismic velocity based on the fracture porosity-seismic velocity crossplot" specifically refers to:

[0023] The minimum value of the fracture porosity is taken as the minimum value of the abscissa of the porosity-seismic velocity crossplot, the maximum value of the fracture porosity is taken as the maximum value of the abscissa of the porosity-seismic velocity crossplot, the intermediate abscissa values are linearly distributed, a fracture porosity-seismic velocity crossplot is formed, and then polynomial curve fitting of the scatter points is performed based on the fracture porosity-seismic velocity crossplot to obtain a fitting relationship between the fracture porosity and the seismic velocity.

[0024] In a second aspect, the present application provides a buried hill inner part fine velocity modeling system based on a reservoir model, comprising:

[0025] A first processing unit is configured to extract small-scale fractures formed by wellbore logging scale fracture extrapolation from well logging imaging data;

[0026] A second processing unit is configured to extract seismic scale fractures and faults from post-stack seismic data;

[0027] A third processing unit is configured to perform fracture spatial distribution trend simulation based on the small-scale fractures formed by wellbore logging scale fracture extrapolation and taking the seismic scale fractures and faults as constraints to obtain a work area fracture model;

[0028] A fourth processing unit is configured to establish a fracture equivalent porosity model based on the work area fracture model and a fracture porosity logging curve obtained through well logging interpretation;

[0029] A fifth processing unit is configured to establish a porosity-seismic velocity crossplot based on the porosity and the seismic velocity in the well logging interpretation result data;

[0030] A sixth processing unit is configured to correct the porosity-seismic velocity crossplot to obtain a fracture porosity-seismic velocity crossplot and establish a fitting relationship between the fracture porosity and the seismic velocity based on the fracture porosity-seismic velocity crossplot;

[0031] A seventh processing unit is configured to map the fracture equivalent porosity model to a velocity model of the buried hill fracture medium according to the fitting relationship between the fracture porosity and the seismic velocity.

[0032] In a third aspect, the present application provides a computer storage medium having a computer program stored thereon, wherein the computer program is executed by a processor to implement the steps of the buried hill inner part fine velocity modeling method of the first aspect of the present application.

[0033] In a fourth aspect, the present application provides a computer device comprising a memory, a processor and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the buried hill inner part fine velocity modeling method of the first aspect of the present application when executing the computer program.

[0034] The present application has the following advantages due to the above technical solutions:

[0035] 1. The present application does not need manual delineation of the cracks in the buried hill interior, and all is automatically generated by the computer, which eliminates the influence of human subjective factors and significantly improves the efficiency of buried hill interior crack reservoir velocity modeling.

[0036] 2. The velocity model established by the present application is mapped from the buried hill interior crack porosity model, which can well reflect the crack distribution characteristics of the buried hill interior, and both seismic scale fractures and cracks and well logging scale cracks are included, which is difficult to achieve by manual buried hill interior velocity modeling.

[0037] The present application has great help and broad application prospects for the increasingly widespread buried hill exploration and buried hill seismic data acquisition at present. BRIEF DESCRIPTION OF DRAWINGS

[0038] Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The accompanying drawings are included to provide a description of the preferred embodiments and are not intended to limit the scope of the present application. Throughout the drawings, like reference numerals will be used to designate like components. In the drawings:

[0039] Figure 1 is a flow chart of the buried hill interior fine velocity modeling method based on the reservoir model provided by an embodiment of the present application;

[0040] Figure 2(a) is a well logging scale crack distribution map extracted from well logging imaging data;

[0041] Figure 2(b) is an ant body extracted from post-stack seismic data;

[0042] Figure 3 is a crack equivalent porosity model;

[0043] Figure 4 is a cross plot of well porosity and seismic velocity and a fitting relationship;

[0044] Figure 5 is a velocity model of the buried hill crack medium;

[0045] Figure 6(a) is a towed cable data migration imaging result obtained by forward modeling based on the buried hill interior crack medium velocity model;

[0046] Figure 6(b) is an 8-line 12-shot seabed cable data migration imaging result obtained by forward modeling based on the buried hill interior crack medium velocity model. DETAILED DESCRIPTION

[0047] In order to make the objects, technical solutions and advantages of the present application clearer, the technical solutions of the present application will be clearly and completely described below with reference to the drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0048] The buried hill internal fine velocity modeling method based on a reservoir model provided by the present application comprises the following steps: extracting small-scale fractures formed by extrapolation of well logging scale fractures; extracting seismic scale fractures and faults; based on the small-scale fractures, taking the seismic scale fractures and faults as constraints to perform fracture spatial distribution trend simulation to obtain a fracture model of a work area; establishing a fracture equivalent porosity model; establishing a porosity-seismic velocity crossplot; correcting the porosity-seismic velocity crossplot to obtain a fracture porosity-seismic velocity crossplot and establish a fitting relationship between the fracture porosity and the seismic velocity; and mapping the fracture equivalent porosity model to a velocity model of a buried hill fracture medium according to the fitting relationship between the fracture porosity and the seismic velocity. The present application can effectively improve the accuracy and efficiency of velocity modeling of a buried hill internal fractured reservoir and reduce the influence of subjective factors of a person when performing fracture velocity modeling by manual fracture delineation.

[0049] The buried hill internal fine velocity modeling method and system based on a reservoir model provided by the embodiments of the present application will be described in detail below with reference to the drawings.

[0050] Embodiment 1

[0051] Please refer to Figure 1 The buried hill internal fine velocity modeling method based on a reservoir model provided by the embodiments of the present application comprises the following steps:

[0052] S100. Extracting small-scale fractures formed by extrapolation of well logging scale fractures from logging imaging data, and FIG. 2(a) shows small-scale fractures formed by extrapolation of well logging scale fractures extracted from logging imaging data. The fractures cannot well reflect the overall fracture and fault development characteristics of the internal part of a buried hill.

[0053] S200. Extracting seismic scale (large-scale) fractures and faults from post-stack seismic data, and FIG. 2(b) shows an ant body formed by ant tracking of post-stack seismic data using Petrel software, which represents seismic scale fractures and faults.

[0054] S300. Based on the small-scale fractures extracted in step S100, taking the seismic scale fractures and faults extracted in step S200 as constraints to perform fracture spatial distribution trend simulation to obtain a fracture model of a work area.

[0055] S400. Based on the fracture porosity logging curve obtained by well logging interpretation and the fracture model of the working area obtained in step S300, a fracture equivalent porosity model is established (as shown in Figure 3 , which can better reflect the development characteristics of fractures and cracks in the buried hill interior);

[0056] S500. Based on the porosity and seismic velocity in the well logging interpretation result data, a crossplot of porosity and seismic velocity is established;

[0057] S600. The crossplot of porosity and seismic velocity obtained in step S500 is corrected to obtain a crossplot of fracture porosity and seismic velocity, and a fitting relationship between fracture porosity and seismic velocity is established based on the crossplot of fracture porosity and seismic velocity;

[0058] S700. According to the fitting relationship between fracture porosity and seismic velocity obtained in step S600, the fracture equivalent porosity model in step S400 is mapped into a velocity model of the buried hill fracture medium.

[0059] In the above embodiment, preferably, in step S300, based on the small-scale fractures extrapolated from the well logging scale fractures extracted in step S100, the seismic scale fractures and cracks extracted in step S200 are introduced as constraints into the Petrel software, and the DFN (Discrete Fracture Network modeling) in the Petrel software is used to simulate the spatial distribution trend of the fractures to obtain the fracture model of the working area.

[0060] In the above embodiment, preferably, in step S400, the fracture porosity logging curve and the fracture model of the working area are introduced into the Petrel software to establish the fracture equivalent porosity model.

[0061] In the above embodiment, preferably, in step S500, by the porosity and seismic velocity in the well logging interpretation result data, the well porosity data and seismic velocity values of different wells in the working area can be plotted to form Figure 4 the crossplot of porosity and seismic velocity (in the figure, the horizontal coordinate is porosity, and the vertical coordinate is seismic velocity) as shown in the figure.

[0062] In the above embodiment, preferably, considering that the abscissa of the crossplot of porosity and seismic velocity in step S500 is the total porosity of the medium, the value of which is mainly determined by the matrix porosity, the total matrix of the buried hill interior is not very different, and thus the matrix porosity has strong uniformity, and the matrix porosity is difficult to represent the fracture characteristics, and thus the distribution characteristics of the velocity are mainly represented by the distribution characteristics of the fractures. Based on this, in step S600, the crossplot of the fracture porosity and the seismic velocity is formed by modifying the abscissa of the crossplot of the porosity and the seismic velocity in step S500, i.e., taking the minimum value of the fracture porosity as the minimum value of the abscissa of the crossplot of the porosity and the seismic velocity, taking the maximum value of the fracture porosity as the maximum value of the abscissa of the crossplot of the porosity and the seismic velocity, and linearly distributing the intermediate abscissa values, and then the polynomial curve fitting of the scattered points is performed based on the crossplot of the fracture porosity and the seismic velocity, to obtain the fitting relationship between the fracture porosity and the seismic velocity.

[0063] Figure 5 The velocity model of the buried hill fracture medium is formed by mapping the fracture equivalent porosity model according to the fitting relationship between the fracture porosity and the seismic velocity, and the velocity model can better represent the fracture and fracture development characteristics of the buried hill interior.

[0064] FIG. 6(a) is the migration imaging result of the streamer data obtained by forward modeling of the velocity model of the buried hill interior fracture medium established based on the method of the present application, and it can be seen that the imaging of the fractures in the buried hill interior is not very clear due to the low configuration of the streamer observation system; FIG. 6(b) is the migration imaging result of the 8-line 12-cannon bottom cable data obtained by forward modeling of the velocity model of the buried hill interior fracture medium established based on the method of the present application, and it can be seen that the imaging of the fractures in the buried hill interior is improved due to the higher configuration of the bottom cable observation system, proving the effectiveness of the acquisition observation system.

[0065] Thus, the method for fine velocity modeling of the buried hill interior based on the reservoir model is realized, the fine velocity model of the buried hill interior is mapped by means of the fitting relationship between the porosity and the velocity on the well, through the fractured reservoir model of the buried hill interior, so as to avoid the problems of low accuracy and low efficiency in manual velocity modeling of the buried hill interior.

[0066] Embodiment 2:

[0067] The embodiment 1 above provides a buried hill inside fine velocity modeling method based on a reservoir model. Correspondingly, the present embodiment provides a buried hill inside fine velocity modeling system based on a reservoir model. The buried hill inside fine velocity modeling system provided by the present embodiment can implement the buried hill inside fine velocity modeling method of the embodiment 1. The system can be implemented by software, hardware or a combination of software and hardware. For example, the system can include integrated or separated functional modules or functional units to perform the corresponding steps in the methods of the embodiment 1. Since the system of the present embodiment is basically similar to the method embodiment, the description process of the present embodiment is relatively simple, and the related parts can be referred to the part of the description of the embodiment 1. The buried hill inside fine velocity modeling system based on a reservoir model provided by the present embodiment is merely illustrative.

[0068] The buried hill inside fine velocity modeling system based on a reservoir model provided by the present embodiment includes:

[0069] The first processing unit is configured to extract small-scale fractures formed by wellbore logging scale fracture extrapolation from the well logging imaging data;

[0070] The second processing unit is configured to extract seismic scale fractures and faults from the post-stack seismic data;

[0071] The third processing unit is configured to perform fracture spatial distribution trend simulation by taking the fractures and faults of the seismic scale as a constraint based on the small-scale fractures formed by the wellbore logging scale fracture extrapolation, to obtain a work area fracture model;

[0072] The fourth processing unit is configured to establish a fracture equivalent porosity model based on the work area fracture model and the fracture porosity logging curve obtained by well logging interpretation;

[0073] The fifth processing unit is configured to establish a crossplot of porosity and seismic velocity based on the porosity and seismic velocity in the well logging interpretation result data;

[0074] The sixth processing unit is configured to correct the crossplot of porosity and seismic velocity, to obtain a crossplot of fracture porosity and seismic velocity, and to establish a fitting relationship between the fracture porosity and the seismic velocity based on the crossplot of fracture porosity and seismic velocity;

[0075] The seventh processing unit is configured to map the fracture equivalent porosity model to a velocity model of the buried hill fracture medium according to the fitting relationship between the fracture porosity and the seismic velocity.

[0076] Embodiment 3:

[0077] The embodiment provides a processing device for implementing the method for modeling fine speed of buried hill inner part based on a reservoir model provided in the embodiment 1. The processing device can be a processing device for a client, such as a mobile phone, a notebook computer, a tablet computer, a desktop computer, etc., to execute the method of the embodiment 1.

[0078] The processing device comprises a processor, a memory, a communication interface and a bus. The processor, the memory and the communication interface are connected through the bus to complete communication with each other. The memory stores a computer program capable of running on the processor. When the processor runs the computer program, the method for modeling fine speed of buried hill inner part based on a reservoir model provided in the embodiment 1 is executed.

[0079] Preferably, the memory can be a high-speed random access memory (RAM) and can also comprise a non-volatile memory, such as at least one disk memory.

[0080] Preferably, the processor can be a central processing unit (CPU), a digital signal processor (DSP) or various types of general-purpose processors, which are not limited here.

[0081] Embodiment 4:

[0082] The method for modeling fine speed of buried hill inner part based on a reservoir model in the embodiment 1 can be specifically implemented as a computer program product. The computer program product can comprise a computer readable storage medium, which is loaded with computer readable program instructions for executing the method described in the embodiment 1.

[0083] The computer readable storage medium can be a tangible device that maintains and stores instructions for use by an instruction execution device. The computer readable storage medium can be, for example but not limited to, an electronic storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any combination of the above.

[0084] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than limit them. Although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that the technical solutions recorded in the foregoing embodiments can be modified, or some or all of the technical features can be replaced equivalently. Such modifications or replacements do not change the essence of the corresponding technical solutions, which should be covered in the scope of the present application. In particular, the technical features mentioned in each embodiment can be combined in any manner as long as there is no structural conflict. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A buried hill inner part fine velocity modeling method based on a reservoir model, characterized in that, The method comprises the following steps: extracting small-scale fractures formed by extrapolation of wellbore logging scale fractures from well imaging data; extracting seismic scale fractures and faults from post-stack seismic data; based on the small-scale fractures formed by extrapolation of wellbore logging scale fractures, taking the seismic scale fractures and faults as constraints, simulating the spatial distribution trend of the fractures to obtain a fracture model of the work area; based on the fracture model of the work area and the fracture porosity logging curve obtained through well logging interpretation, establishing a fracture equivalent porosity model; based on the porosity and seismic velocity in the well logging interpretation result data, establishing a crossplot of porosity and seismic velocity; correcting the crossplot of porosity and seismic velocity to obtain a crossplot of fracture porosity and seismic velocity, and establishing a fitting relationship between fracture porosity and seismic velocity based on the crossplot of fracture porosity and seismic velocity; mapping the fracture equivalent porosity model to a velocity model of buried hill fractured media according to the fitting relationship between fracture porosity and seismic velocity.

2. The buried hill inner part fine velocity modeling method according to claim 1, characterized in that, The seismic scale fractures and faults are ant bodies formed by ant tracking of the post-stack seismic data using Petrel software.

3. The buried hill inner part fine velocity modeling method according to claim 1, characterized in that, The "based on the small-scale fractures formed by extrapolation of wellbore logging scale fractures, taking the seismic scale fractures and faults as constraints, simulating the spatial distribution trend of the fractures to obtain a fracture model of the work area" specifically refers to: based on the small-scale fractures formed by extrapolation of wellbore logging scale fractures, taking the seismic scale fractures and faults as constraints, importing them into Petrel software, and using the discrete fracture network modeling in Petrel software to simulate the spatial distribution trend of the fractures to obtain a fracture model of the work area.

4. The buried hill inner part fine velocity modeling method according to claim 3, characterized in that, The "based on the fracture model of the work area and the fracture porosity logging curve obtained through well logging interpretation, establishing a fracture equivalent porosity model" specifically refers to: importing the fracture porosity logging curve and the fracture model of the work area into Petrel software to establish a fracture equivalent porosity model.

5. The buried hill inner part fine velocity modeling method according to claim 4, characterized in that, The "based on the porosity and seismic velocity in the well logging interpretation result data, establishing a crossplot of porosity and seismic velocity" specifically refers to: based on the porosity and seismic velocity in the well logging interpretation result data, plotting the porosity data and seismic velocity values of different wells in the work area to form a crossplot of porosity and seismic velocity.

6. The buried hill inner part fine velocity modeling method according to claim 5, characterized in that, The "correcting the crossplot of porosity and seismic velocity to obtain a crossplot of fracture porosity and seismic velocity, and establishing a fitting relationship between fracture porosity and seismic velocity based on the crossplot of fracture porosity and seismic velocity" specifically refers to: taking the minimum value of fracture porosity as the minimum value of the abscissa of the crossplot of porosity and seismic velocity, taking the maximum value of fracture porosity as the maximum value of the abscissa of the crossplot of porosity and seismic velocity, linearly distributing the intermediate abscissa values to form a crossplot of fracture porosity and seismic velocity, and then performing polynomial curve fitting on the scattered points based on the crossplot of fracture porosity and seismic velocity to obtain a fitting relationship between fracture porosity and seismic velocity.

7. A buried hill inner part fine velocity modeling system based on a reservoir model, characterized by, The method comprises: a first processing unit configured to extract small-scale fractures formed by extrapolation of wellbore logging scale fractures from well imaging data; a second processing unit configured to extract seismic scale fractures and faults from post-stack seismic data; The third processing unit is configured to simulate a spatial distribution trend of fractures based on small-scale fractures formed by extrapolation of well-logging scale fractures, and take seismic scale fractures and cracks as constraints to obtain a fracture model of the work area; The fourth processing unit is configured to establish a fracture equivalent porosity model based on the fracture model of the work area and a fracture porosity logging curve obtained by well-logging interpretation; The fifth processing unit is configured to establish a crossplot of porosity and seismic velocity based on porosity and seismic velocity in the well-logging interpretation result data; The sixth processing unit is configured to correct the crossplot of porosity and seismic velocity to obtain a crossplot of fracture porosity and seismic velocity, and establish a fitting relationship between fracture porosity and seismic velocity based on the crossplot of fracture porosity and seismic velocity; The seventh processing unit is configured to map the fracture equivalent porosity model to a velocity model of buried-hill fracture media according to the fitting relationship between fracture porosity and seismic velocity.

8. A computer storage medium having stored thereon a computer program, characterized in that The computer program, when executed by a processor, implements the steps of the buried-hill internal fine velocity modeling method of any one of claims 1-6.

9. A computer device comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, The processor, when executing the computer program, implements the steps of the buried-hill internal fine velocity modeling method of any one of claims 1-6.

Images