A method and device for constructing a seismic velocity body

Abstract

The present invention discloses a method and device for constructing a seismic velocity body. The method comprises: selecting the time-depth relationship of the drilled wells in the target area that meets the requirements based on the synthetic seismic records and actual seismic records of the drilled wells in the target area; determining the velocity data of the drilled wells according to the time-depth relationship of the drilled wells; extracting the preferred seismic attributes related to the target layer based on the velocity data, the seismic interpretation layer of the target layer and the seismic data body; fitting the layer velocity body of the target layer based on the time-depth relationship of the drilled wells, the seismic interpretation layer and the seismic attributes related to the target layer and the pre-established time structure model of the target layer; establishing the average velocity body from the surface to the target layer based on the layer velocity body of the target layer to obtain the seismic velocity body of the target area. It can effectively guide the preferred exploration target of the target area, improve the success rate of the deployment of exploration wells, optimize the drilling footage, save drilling costs, and improve the exploration efficiency of the early exploration blocks.

Description

Technical Field

[0001] The present invention relates to the technical field of oil and gas field exploration, and in particular to a method and device for constructing a seismic velocity body. Background Art

[0002] As the exploration of oil and gas basins continues to improve, underground conditions are becoming increasingly complex, resource grades are deteriorating, and the depth of target layers is increasing. By constructing seismic velocity bodies in exploration and evaluation blocks, rapid and efficient exploration work can be carried out in the exploration area to ensure the implementation of large-scale high-quality reserves, achieve energy succession, stabilize oil and gas development, and ensure energy security.

[0003] The accuracy of seismic velocity body construction in exploration and evaluation blocks not only affects the accuracy of structural map compilation and the accuracy of oil and gas resource scale description, but also directly affects the success rate of exploration well deployment and implementation. Therefore, how to use existing well completion and seismic data to construct a fine and accurate velocity body is of great significance to the rapid and efficient exploration of exploration blocks at home and abroad.

[0004] At present, the velocity body construction method mainly uses geological stratification, single well time-depth relationship and velocity spectrum data to construct the velocity body. Summary of the invention

[0005] The inventors of the present invention have found that the existing technologies for constructing velocity bodies have at least the following problems:

[0006] The existing velocity body construction method only uses the velocity spectrum data picked up from seismic to constrain the velocity body in areas where no wells have been drilled. Since the lateral resolution of the velocity spectrum data is not high, it is not closely related to the underground lithology information, and there is no velocity spectrum data in some areas, so there is a multiple solution problem, and the velocity body constructed in this way will also be inaccurate. In addition, factors such as limited drilling data in the early stage of exploration and uneven quality of seismic data will also cause the constructed velocity body to be inaccurate.

[0007] In view of the above problems, the present invention is proposed to provide a seismic velocity body method and apparatus that overcome the above problems or at least partially solve the above problems.

[0008] In a first aspect, an embodiment of the present invention provides a method for constructing a seismic velocity body, comprising:

[0009] Based on synthetic seismic records and actual seismic records of wells drilled in the target area, the time-depth relationship of wells drilled in the target area that meet the requirements is selected;

[0010] Determine the velocity data of the drilled wells according to the time-depth relationship of the drilled wells, and extract the preferred seismic attributes related to the target layer based on the velocity data, the seismic interpretation horizon of the target layer and the seismic data volume. The seismic attributes include the attributes that reflect the structure and lithology;

[0011] According to the time-depth relationship of the drilled wells, the seismic interpretation level and the seismic attributes related to the target layer, the interlayer velocity body of the target layer is fitted based on the pre-established time-structure model of the target layer;

[0012] Based on the layer velocity body of the target layer, the average velocity body from the surface to the target layer is established to obtain the seismic velocity body of the target area.

[0013] In some optional embodiments, based on synthetic seismic records and actual seismic records of wells drilled in the target area, selecting the time-depth relationship of wells drilled in the target area that meet the requirements includes:

[0014] Based on the logging data and Ricker wavelet of the wells already drilled in the target area, the synthetic seismic records of the wells already drilled in the target area are obtained by forward simulation;

[0015] The synthetic seismic records of the drilled wells are compared with the actual seismic records, and the time-depth relationship of the drilled wells that meet the requirements in the target area is selected.

[0016] In some optional embodiments, based on the well logging data and Ricker wavelet of the wells already drilled in the target area, forward simulation is performed to obtain synthetic seismic records of the wells already drilled in the target area, including:

[0017] Collect well logging data and Ricker wavelet of the wells drilled in the target area;

[0018] The logging data of the drilled wells including the acoustic time difference and density curve are obtained to determine the reflection coefficient reflecting the formation reflection information, and the synthetic seismic record of each drilled well is simulated according to the formation reflection coefficient and the Ricker wavelet of the preset frequency.

[0019] In some optional embodiments, synthetic seismic records of drilled wells are compared with actual seismic records to select time-depth relationships of drilled wells that meet the requirements in the target area, including:

[0020] The seismic waveform characteristics of the synthetic seismic records and the actual seismic records are compared to determine the correlation coefficient of the seismic waveform characteristics of the synthetic seismic records and the actual seismic records, and the synthetic seismic records whose correlation coefficients reach the preset first correlation coefficient threshold are selected to obtain the time-depth relationship of the drilled well that meets the requirements; the time-depth relationship refers to the correspondence between the time for the seismic wave to run to the actual depth and the actual depth.

[0021] In some optional embodiments, velocity data of the drilled well is determined according to the time-depth relationship of the drilled well, and based on the velocity data, the seismic interpretation horizon of the target layer and the seismic data volume, the preferred seismic attributes related to the target layer are extracted, including:

[0022] Obtain seismic attributes reflecting structure and lithology based on seismic data volumes;

[0023] Extracting seismic attribute data at the seismic interpretation layer of the target layer according to the seismic attribute and the seismic interpretation layer of the target layer;

[0024] Fitting seismic attribute correlation curves based on the velocity data of the drilled well and the seismic attribute data at the target layer seismic interpretation layer;

[0025] Seismic attributes whose seismic attribute correlation coefficients in the correlation curve exceed a preset second correlation coefficient threshold are extracted as preferred target layer-related seismic attributes.

[0026] In some optional embodiments, according to the time-depth relationship of the drilled well, the seismic interpretation level and the seismic attributes related to the target layer, based on the pre-established time structure model of the target layer, the layer velocity body of the target layer is fitted, including:

[0027] Setting control weights of preferred seismic attributes based on seismic attribute correlation coefficients;

[0028] Taking the time-depth relationship of the drilled wells as the reference control point and the seismic interpretation level as the constraint, for each seismic interpretation level, according to the velocity of the drilled wells in the pre-established time-structure model of the target layer and the seismic attribute control weight, the velocity between wells is fitted to obtain the velocity distribution data of each seismic interpretation level;

[0029] Generate the target layer's interlayer velocity volume based on the velocity distribution data of each seismic interpretation layer;

[0030] The weight of the structural attribute included in the seismic attributes is greater than the preset weight, and the weight of the lithological attribute is less than the preset weight.

[0031] In some optional embodiments, establishing a target layer time structure model includes:

[0032] Pick up the time layer of the target area, which includes the top and bottom of the target layer and multiple intermediate control time layers;

[0033] A time structure model of the target layer is established based on the time plane picked up by the reflection axis of the seismic profile. The time structure model takes the boundary of the target area as the horizontal boundary and the top and bottom surfaces of the seismic interpretation plane of the target area as the vertical boundaries.

[0034] In some optional embodiments, based on the interval velocity body of the target layer, an average velocity body from the surface to the target layer is established to obtain a seismic velocity body of the target area, including:

[0035] Based on the layer velocity body of the target layer, the layer average velocity body of each layer in the target layer is obtained;

[0036] Taking the surface as the top layer, the layer average velocity volume from the surface to the top surface of the target layer and each layer in the target layer is superimposed to obtain the average velocity volume from the surface to the target layer.

[0037] In a second aspect, an embodiment of the present invention provides a seismic velocity body construction device, comprising:

[0038] A time-depth relationship determination module is used to select the time-depth relationship of the drilled wells that meet the requirements in the target area based on the synthetic seismic records and actual seismic records of the drilled wells in the target area;

[0039] A seismic attribute extraction module is used to determine the velocity data of the drilled well according to the time-depth relationship of the drilled well, and extract the preferred seismic attributes related to the target layer based on the velocity data, the seismic interpretation horizon of the target layer and the seismic data volume. The seismic attributes include attributes that reflect the structure and lithology;

[0040] The velocity body construction module is used to fit the layer velocity body of the target layer based on the pre-established time-depth relationship of the drilled well, the seismic interpretation level and the relevant seismic attributes of the target layer, and to establish the average velocity body from the surface to the target layer based on the layer velocity body of the target layer to obtain the seismic velocity body of the target area.

[0041] An embodiment of the present invention further provides a computer storage medium storing computer executable instructions, and when the computer executable instructions are executed by a processor, the above-mentioned seismic velocity body construction method is implemented.

[0042] An embodiment of the present invention further provides a computer device, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the above-mentioned seismic velocity body method is implemented when the processor executes the program.

[0043] The beneficial effects of the above technical solution provided by the embodiment of the present invention include at least:

[0044] Based on the synthetic seismic records and actual seismic records of the drilled wells in the target area, the time-depth relationship of the drilled wells that meet the requirements in the target area is selected; the velocity data of the drilled wells is determined according to the time-depth relationship of the drilled wells, and based on the velocity data, the seismic interpretation layer of the target layer and the seismic data body, the preferred target layer related seismic attributes are extracted, and the seismic attributes include the attributes of the reaction structure and lithology; in the traditional velocity body construction method, the velocity spectrum data has a low lateral resolution and is not closely related to the underground lithology information, so the constructed velocity body is not accurate enough. This method extracts the attributes closely related to the underground lithology according to the correlation coefficient, and participates in the construction of the velocity body, which can improve the accuracy of the velocity body.

[0045] According to the time-depth relationship of the drilled wells, the seismic interpretation level and the relevant seismic attributes of the target layer, the layer velocity body of the target layer is fitted based on the pre-established time-tectonic model of the target layer; according to the seismic interpretation level and the seismic related attributes, the size of the correlation coefficient is used as the constraint weight for velocity body construction, forming a velocity body construction method controlled by seismic attributes with different weights under the constraints of the seismic interpretation level, which greatly improves the accuracy of velocity body construction.

[0046] Based on the layer velocity body of the target layer, the average velocity body from the surface to the target layer is established to obtain the seismic velocity body of the target area. Since only the drilled areas have velocity in the layer velocity body, but there is no velocity data in the undrilled areas, the average velocity of the layer is used as a constraint to perform plane interpolation, and finally the average velocity body of the layer is obtained. The average velocity body of each layer is superimposed to obtain the final seismic velocity body. This method solves the problem of inaccurate velocity body establishment caused by limited early exploration drilling data and uneven seismic data quality in traditional methods, effectively guides the optimization of exploration targets in the target area, improves the success rate of deployment of exploration wells, optimizes drilling footage, saves drilling costs, and improves the exploration efficiency of early exploration blocks.

[0047] 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 particularly pointed out in the written description, claims, and drawings.

[0048] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0050] Figure 1 A flowchart of a method for constructing a seismic velocity volume in an embodiment of the present invention;

[0051] Figure 2 It is a time-depth relationship curve diagram in an embodiment of the present invention;

[0052] Figure 3 A three-dimensional spatial schematic diagram of a seismic interpretation layer in an embodiment of the present invention;

[0053] Figure 4 A schematic diagram of an earthquake profile in an embodiment of the present invention;

[0054] Figure 5 This is an example diagram of a time structure model diagram in an embodiment of the present invention;

[0055] Figure 6 A schematic diagram of a depth structure diagram in an embodiment of the present invention;

[0056] Figure 7 It is a seismic velocity body construction device in an embodiment of the present invention. DETAILED DESCRIPTION

[0057] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0058] In order to solve the problem of inaccurate velocity body establishment caused by factors such as limited early exploration drilling data and uneven quality of seismic data in the prior art, an embodiment of the present invention provides a seismic velocity construction method based on seismic interpretation level and seismic attribute body constraints, thereby improving the success rate of deploying exploratory wells, optimizing drilling footage, saving drilling costs, and improving the exploration efficiency of early exploration blocks.

[0059] Example

[0060] The embodiment of the present invention provides a method for constructing a seismic velocity body, the process of which is as follows: Figure 1 As shown, the following steps are included:

[0061] Step S101: based on synthetic seismic records and actual seismic records of wells drilled in the target area, selecting time-depth relationships of wells drilled in the target area that meet the requirements;

[0062] Step S102: Determine the velocity data of the drilled well according to the time-depth relationship of the drilled well, and extract the preferred seismic attributes related to the target layer based on the velocity data, the seismic interpretation horizon of the target layer and the seismic data volume, wherein the seismic attributes include attributes that reflect the structure and lithology;

[0063] Step S103: fitting the target layer's interlayer velocity volume based on the pre-established target layer temporal structural model according to the time-depth relationship of the wells that have been drilled, the seismic interpretation level and the seismic attributes related to the target layer;

[0064] Step S104: Based on the layer velocity body of the target layer, an average velocity body from the surface to the target layer is established to obtain the seismic velocity body of the target area.

[0065] Preferably, in the above step S101, based on the synthetic seismic records and actual seismic records of the wells drilled in the target area, selecting the time-depth relationship of the wells drilled in the target area that meet the requirements includes:

[0066] Based on the logging data and Ricker wavelet of the wells already drilled in the target area, the synthetic seismic records of the wells already drilled in the target area are obtained by forward simulation;

[0067] The synthetic seismic records of the drilled wells are compared with the actual seismic records, and the time-depth relationship of the drilled wells that meet the requirements in the target area is selected.

[0068] During the implementation process, technicians conducted forward modeling on each drilled well to obtain synthetic seismic records, which are fitted seismic waves.

[0069] Preferably, the synthetic seismic records of the wells drilled in the target area are obtained by forward simulation based on the well logging data and Ricker wavelet of the wells drilled in the target area, including:

[0070] Collect well logging data and Ricker wavelet of the wells drilled in the target area;

[0071] The logging data of the drilled wells including the acoustic time difference and density curve are obtained to determine the reflection coefficient reflecting the formation reflection information, and the synthetic seismic record of each drilled well is simulated according to the formation reflection coefficient and the Ricker wavelet of the preset frequency.

[0072] Preferably, the synthetic seismic records of the drilled wells are compared with the actual seismic records, and the time-depth relationship of the drilled wells in the target area that meets the requirements is selected, including:

[0073] The seismic waveform characteristics of the synthetic seismic records and the actual seismic records are compared to determine the correlation coefficient of the seismic waveform characteristics of the synthetic seismic records and the actual seismic records, and the synthetic seismic records whose correlation coefficients reach a preset first correlation coefficient threshold are selected to obtain a time-depth relationship of the drilled well that meets the requirements; the time-depth relationship refers to the correspondence between the time for the seismic wave to run to the actual depth and the actual depth.

[0074] In this embodiment, the synthetic seismic record is moved up and down by the time-depth calibration software to compare the seismic waveform characteristics of the synthetic seismic record with the actual seismic record. If the two waveforms are more similar, the correlation coefficient will be higher. If the first correlation coefficient threshold of the two reaches more than 85%, the time-depth relationship of each well can be obtained. The first correlation coefficient threshold can be adjusted according to the quality of the seismic record. The time-depth relationship of most of the drilled wells basically overlaps with the curve you get. Eliminate individual non-overlapping time-depth relationships, and eventually you can get a detailed time-depth relationship in the vertical direction of most of the drilled wells. For the time-depth relationship curve, see Figure 2 As shown, Figure 2 The horizontal axis is depth and the vertical axis is time. It can be seen from the figure that several fitted time-depth relationship curves basically coincide with each other.

[0075] Preferably, in the above step S102, velocity data of the drilled well is determined according to the time-depth relationship of the drilled well, and based on the velocity data, the seismic interpretation horizon of the target layer and the seismic data volume, the preferred seismic attributes related to the target layer are extracted, including:

[0076] Obtain seismic attributes reflecting structure and lithology based on seismic data volumes;

[0077] Extracting seismic attribute data at the seismic interpretation layer of the target layer according to the seismic attribute and the seismic interpretation layer of the target layer;

[0078] Fitting seismic attribute correlation curves based on the velocity data of the drilled well and the seismic attribute data at the target layer seismic interpretation layer;

[0079] Seismic attributes whose seismic attribute correlation coefficients in the correlation curve exceed a preset second correlation coefficient threshold are extracted as preferred target layer-related seismic attributes.

[0080] Seismic attributes are the properties of structure and rock type obtained through seismic data bodies, such as structural dip, root mean square amplitude, amplitude energy, etc. The structure and rock type are the direct causes of changes in the velocity body. The velocity data of each well can be determined by the time-depth relationship of the completed well. One of the well logging data is the acoustic time difference curve. The inverse of the time difference is the velocity. Therefore, if the well is logged after drilling, there will be velocity data. The velocity data of each well and the seismic attribute data extracted from the position of the seismic interpretation layer of each well are used to establish a fitting correlation curve. The seismic attributes with a second correlation coefficient threshold exceeding 60% are selected and applied to the establishment of the velocity body. The second correlation coefficient threshold can be adjusted according to the seismic data of different target areas.

[0081] Preferably, in the above step S103, according to the time-depth relationship of the drilled well, the seismic interpretation level and the seismic attributes related to the target layer, based on the pre-established time structure model of the target layer, the interval velocity body of the target layer is fitted, including:

[0082] Setting control weights of preferred seismic attributes based on seismic attribute correlation coefficients;

[0083] Taking the time-depth relationship of the drilled wells as the reference control point and the seismic interpretation level as the constraint, for each seismic interpretation level, according to the velocity of the drilled wells in the pre-established time-structure model of the target layer and the seismic attribute control weight, the velocity between wells is fitted to obtain the velocity distribution data of each seismic interpretation level;

[0084] The seismic interpretation level is the time level of the reflection axis picked up by the seismic interpretation software. Figure 3 As shown, Figure 3There are 6 layers of seismic interpretation, and there are time-depth relationship lines of several points on the layers. According to the time-depth relationship, the velocity data of the point can be obtained. Both the seismic interpretation layer and the seismic related attributes play a very important role in controlling the velocity body in the unfinished drilling area, and neither of them can be missing.

[0085] Generate the target layer's interlayer velocity volume based on the velocity distribution data of each seismic interpretation layer;

[0086] The weight of the structural attribute included in the seismic attribute is greater than the preset weight, and the lithology attribute is less than the preset weight. The structural attributes include: structural coherence body, curvature body, structural dip body, etc., and 1-2 attributes can be selected for constraint. Because the structural attribute is closely related to the velocity, the weight is greater than 50%. Other attributes include: amplitude attribute body, frequency attribute body, seismic sweet spot attribute body, etc. These are related to lithology and indirectly related to velocity. 1-2 attributes can be selected for constraint, but the weight should be less than 50%.

[0087] First, we have a time structure model and velocity data for each well, but only a few points have velocity data. Therefore, the velocity between wells depends on the seismic interpretation level and seismic attribute control, and plane interpolation is performed to obtain a complete plane velocity distribution map. The velocity body is obtained by adding all the surfaces together vertically.

[0088] Preferably, establishing a target layer time structure model includes:

[0089] Pick up the time layer of the target area, which includes the top and bottom of the target layer and multiple intermediate control time layers;

[0090] A time structure model of the target layer is established based on the time plane picked up by the reflection axis of the seismic profile. The time structure model takes the boundary of the target area as the horizontal boundary and the top and bottom surfaces of the seismic interpretation plane of the target area as the vertical upper boundary.

[0091] See the seismic section for Figure 4 As shown. The structural model is a time structural model established by applying all time levels. In practice, the establishment of the time structural model is based on the boundary of the target area in the plane, and the size of the plane grid is appropriately adjusted according to the area of ​​the target area, but it must be smaller than the distance of the completed drilling; the top and bottom surfaces of the seismic interpretation layer of the target layer are used as boundaries in the vertical direction, and the size of the vertical grid is appropriately adjusted according to the thickness of the target layer, but it must be smaller than the thickness of the two adjacent seismic interpretation layers. For the time structural model diagram of the target area, see Figure 5 As shown, several levels of seismic interpretation are included.

[0092] Preferably, based on the layer velocity body of the target layer, an average velocity body from the surface to the target layer is established to obtain the seismic velocity body of the target area, including:

[0093] Based on the layer velocity body of the target layer, the layer average velocity body of each layer in the target layer is obtained;

[0094] Taking the surface as the top layer, the layer average velocity volume from the surface to the top surface of the target layer and each layer in the target layer is superimposed to obtain the average velocity volume from the surface to the target layer.

[0095] Based on the constraints of seismic interpretation levels and seismic attributes in the layer velocity body of the target layer, the average velocity of each well is obtained. The layer velocity body of each layer is spatially interpolated using the average velocity of each layer, and the layer velocity body of each layer can be converted into a layer average velocity body. Finally, the layer average velocity body of each layer is superimposed to obtain the entire average velocity body from the surface to the target layer, and the final seismic velocity body is obtained. Each well will obtain a depth value of the geological boundary through logging. The depth value of each layer of all wells is involved in the establishment of the velocity body. After the time is converted into depth, the depth of each layer corresponding to each well is corrected correctly, and the time seismic layer can be converted into a depth layer, and finally the accurate seismic velocity body of the target area is obtained. Seismic data collects underground time values, that is, the time taken for seismic waves to be emitted from the ground to the underground and then reflected back to the ground. Only a time structure map can be obtained. By establishing a velocity body and converting the time structure map into a depth structure map, the depth value corresponding to each point can be known, so that exploration work can be carried out more effectively. Figure 6 This is a depth structure map. The well locations of ET-1, ET-2, ..., and ET-28 are selected in the map. The structural depth error table corresponding to the depth structure map obtained by the established seismic velocity body is shown in Table 1. The actual depth from the surface to the target layer is about 2600m, and the actual altitude error is controlled within 20m. It is predicted that if the actual depth from the surface to the target layer is about 5000m, the actual altitude error will be within 50m, while the error of the prior art is 100m, which proves that the velocity body constructed by this method can predict the depth more accurately.

[0096] Table 1

[0097]

[0098] Based on the same inventive concept, an embodiment of the present invention further provides a seismic velocity body construction device, which can be arranged in a device capable of processing computer instructions. The structure of the device is as follows: Figure 7 As shown, including:

[0099] The time-depth relationship determination module 11 is used to select the time-depth relationship of the drilled wells in the target area that meets the requirements based on the synthetic seismic records and actual seismic records of the drilled wells in the target area;

[0100] A seismic attribute extraction module 12 is used to determine the velocity data of the drilled well according to the time-depth relationship of the drilled well, and extract the preferred seismic attributes related to the target layer based on the velocity data, the seismic interpretation horizon of the target layer and the seismic data volume, wherein the seismic attributes include attributes that reflect the structure and lithology;

[0101] The velocity body construction module 13 is used to fit the layer velocity body of the target layer based on the pre-established time-depth relationship of the drilled well, the seismic interpretation level and the relevant seismic attributes of the target layer, and to establish an average velocity body from the surface to the target layer based on the layer velocity body of the target layer to obtain the seismic velocity body of the target area.

[0102] Regarding the seismic velocity body construction device in the above embodiment, the specific manner in which each module performs operations has been described in detail in the embodiment of the method, and will not be elaborated here.

[0103] The above-mentioned method and device of the embodiment of the present invention select the time-depth relationship of the drilled wells in the target area that meets the requirements based on the synthetic seismic records and actual seismic records of the drilled wells in the target area; determine the velocity data of the drilled wells according to the time-depth relationship of the drilled wells, and extract the preferred target layer related seismic attributes based on the velocity data, the seismic interpretation layer of the target layer and the seismic data body, and the seismic attributes include the attributes of the reaction structure and lithology; this method extracts the attributes closely related to the underground lithology according to the correlation coefficient, participates in the construction of the velocity body, and can improve the accuracy of the velocity body.

[0104] According to the time-depth relationship of the drilled wells, the seismic interpretation level and the relevant seismic attributes of the target layer, the layer velocity body of the target layer is fitted based on the pre-established time-tectonic model of the target layer; according to the seismic interpretation level and the seismic related attributes, the size of the correlation coefficient is used as the constraint weight for velocity body construction, forming a velocity body construction method controlled by seismic attributes with different weights under the constraints of the seismic interpretation level, which greatly improves the accuracy of velocity body construction.

[0105] Based on the layer velocity body of the target layer, the average velocity body from the surface to the target layer is established to obtain the seismic velocity body of the target area. Since only the drilled areas have velocity in the layer velocity body, but there is no velocity data in the undrilled areas, the average velocity of the layer is used as a constraint to perform plane interpolation, and finally the average velocity body of the layer is obtained. The average velocity body of each layer is superimposed to obtain the final seismic velocity body. This method solves the problem of inaccurate velocity body establishment caused by limited early exploration drilling data and uneven seismic data quality in traditional methods, effectively guides the optimization of exploration targets in the target area, improves the success rate of deployment of exploration wells, optimizes drilling footage, saves drilling costs, and improves the exploration efficiency of early exploration blocks.

[0106] Unless otherwise specifically stated, terms such as processing, computing, calculating, determining, displaying, etc. may refer to the actions and / or processes of one or more processing or computing systems, or similar devices, which operate and convert data represented as physical (e.g., electronic) quantities within registers or memories of a processing system into other data similarly represented as physical quantities within memories, registers, or other such information storage, transmission, or display devices of the processing system. Information and signals may be represented using any of a variety of different techniques and methods. For example, data, instructions, commands, information, signals, bits, symbols, and chips mentioned throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, light fields or particles, or any combination thereof.

[0107] It should be understood that the specific order or hierarchy of steps in the disclosed process is an example of an exemplary method. Based on design preferences, it should be understood that the specific order or hierarchy of steps in the process can be rearranged without departing from the scope of protection of the present disclosure. The attached method claims present the elements of the various steps in an exemplary order and are not intended to be limited to the specific order or hierarchy described.

[0108] In the above detailed description, various features are grouped together in a single embodiment to simplify the disclosure. This method of disclosure should not be interpreted as reflecting an intention that the embodiments of the claimed subject matter require more features than are clearly stated in each claim. On the contrary, as reflected in the appended claims, the invention is in a state of having less than all the features of the disclosed individual embodiments. Therefore, the appended claims are hereby expressly incorporated into the detailed description, with each claim standing on its own as a separate preferred embodiment of the invention.

[0109] Those skilled in the art will also appreciate that the various illustrative logic blocks, modules, circuits, and algorithmic steps described in conjunction with the embodiments herein can all be implemented as electronic hardware, computer software, or a combination thereof. In order to clearly illustrate the interchangeability between hardware and software, various illustrative components, blocks, modules, circuits, and steps are generally described above around their functions. Whether such functions are implemented as hardware or software depends on specific applications and the design constraints imposed on the entire system. A skilled person can implement the described functions in an alternative manner for each specific application, but such implementation decisions should not be interpreted as departing from the scope of protection of the present disclosure.

[0110] The steps of the method or algorithm described in conjunction with the embodiments herein may be directly embodied as hardware, a software module executed by a processor, or a combination thereof. The software module may be located in a RAM memory, a flash memory, a ROM memory, an EPROM memory, an EEPROM memory, a register, a hard disk, a mobile disk, a CD-ROM, or any other form of storage medium well known in the art. An exemplary storage medium is connected to the processor so that the processor can read information from the storage medium and can write information to the storage medium. Of course, the storage medium may also be an integral part of the processor. The processor and the storage medium may be located in an ASIC. The ASIC may be located in a user terminal. Of course, the processor and the storage medium may also be present in a user terminal as discrete components.

[0111] For software implementation, the techniques described in this application can be implemented with modules (e.g., procedures, functions, etc.) that perform the functions described in this application. These software codes can be stored in a memory unit and executed by a processor. The memory unit can be implemented within the processor or outside the processor. In the latter case, it is coupled to the processor in a communication manner via various means, which are well known in the art.

[0112] The above description includes examples of one or more embodiments. Of course, it is impossible to describe all possible combinations of components or methods for the purpose of describing the above embodiments, but it should be recognized by those skilled in the art that the various embodiments may be further combined and arranged. Therefore, the embodiments described herein are intended to cover all such changes, modifications and variations that fall within the scope of protection of the appended claims. In addition, with respect to the term "comprising" used in the specification or claims, the word is covered in a manner similar to the term "including", just as "including," is explained as a transitional word in the claims. In addition, any term "or" used in the specification of the claims is intended to mean "non-exclusive or".

Claims

1. A method for constructing a seismic velocity volume, characterized in that: include: Based on synthetic seismic records and actual seismic records of wells drilled in the target area, the time-depth relationship of wells drilled in the target area that meet the requirements is selected; Determine the velocity data of the drilled well according to the time-depth relationship of the drilled well, fit the seismic attribute correlation curve based on the velocity data of the drilled well and the pre-extracted seismic attribute data at the seismic interpretation layer of the target layer, and extract the seismic attributes whose seismic attribute correlation coefficient in the correlation curve exceeds a preset second correlation coefficient threshold as the preferred target layer related seismic attributes, wherein the seismic attributes include attributes reflecting structure and lithology; Taking the time-depth relationship of the drilled well as the reference control point and the seismic interpretation level as the constraint, for each seismic interpretation level, the velocity between wells is fitted according to the control weights of the velocity of the drilled well and the seismic attributes related to the target layer in the pre-established time structure model of the target layer, and the velocity distribution data of each seismic interpretation level is obtained, wherein the control weight is set based on the seismic attribute correlation coefficient; According to the velocity distribution data of each seismic interpretation layer, the layer velocity body of the target layer is obtained; Based on the layer velocity body of the target layer, an average velocity body from the surface to the target layer is established to obtain the seismic velocity body of the target area.

2. The method according to claim 1, characterized in that Based on the synthetic seismic records and actual seismic records of the wells drilled in the target area, the time-depth relationship of the wells drilled in the target area that meet the requirements is selected, including: Based on the logging data and Ricker wavelet of the wells already drilled in the target area, the synthetic seismic records of the wells already drilled in the target area are obtained by forward simulation; The synthetic seismic records of the drilled wells are compared with the actual seismic records, and the time-depth relationship of the drilled wells that meet the requirements in the target area is selected.

3. The method according to claim 2, characterized in that The synthetic seismic records of the wells drilled in the target area are obtained by forward simulation based on the well logging data and Ricker wavelet of the wells drilled in the target area, including: Collect well logging data and Ricker wavelet of the wells drilled in the target area; The logging data of the drilled wells including the acoustic time difference and density curve are obtained to determine the reflection coefficient reflecting the formation reflection information, and the synthetic seismic record of each drilled well is simulated according to the formation reflection coefficient and the Ricker wavelet of the preset frequency.

4. The method according to claim 2, characterized in that The synthetic seismic records of the drilled wells are compared with the actual seismic records to select the time-depth relationship of the drilled wells in the target area that meets the requirements, including: The seismic waveform characteristics of the synthetic seismic records and the actual seismic records are compared to determine the correlation coefficient of the seismic waveform characteristics of the synthetic seismic records and the actual seismic records, and the synthetic seismic records whose correlation coefficients reach a preset first correlation coefficient threshold are selected to obtain a time-depth relationship of the drilled well that meets the requirements; the time-depth relationship refers to the correspondence between the time for the seismic wave to run to the actual depth and the actual depth.

5. The method according to claim 1, characterized in that The extracted seismic attribute data at the target layer seismic interpretation layer includes: Obtain seismic attributes reflecting structure and lithology based on seismic data volumes; Seismic attribute data at the seismic interpretation layer of the target layer is extracted according to the seismic attribute and the seismic interpretation layer of the target layer.

6. The method according to claim 1, characterized in that The seismic attributes include a structural attribute whose control weight is greater than a preset weight, and a lithological attribute whose control weight is less than a preset weight.

7. The method according to claim 1, characterized in that Establish the time structure model of the target layer, including: Picking up the time plane of the target area, wherein the time plane includes the top and bottom of the target layer and a plurality of intermediate control time planes; A time structure model of the target layer is established based on the time plane picked up by the reflection axis of the seismic profile. The time structure model takes the boundary of the target area as the horizontal boundary and the top and bottom surfaces of the seismic interpretation plane of the target area as the vertical boundaries.

8. The method according to claim 1, characterized in that The step of establishing an average velocity body from the surface to the target layer based on the layer velocity body of the target layer to obtain a seismic velocity body of the target area includes: Based on the layer velocity body of the target layer, obtaining a layer average velocity body of each layer in the target layer; Taking the surface as the top layer, the layer average velocity volume from the surface to the top surface of the target layer and each layer in the target layer is superimposed to obtain the average velocity volume from the surface to the target layer.

9. A seismic velocity body construction device, characterized in that: include: A time-depth relationship determination module is used to select the time-depth relationship of the drilled wells that meet the requirements in the target area based on the synthetic seismic records and actual seismic records of the drilled wells in the target area; A seismic attribute extraction module is used to determine the velocity data of the drilled well according to the time-depth relationship of the drilled well, fit the seismic attribute correlation curve based on the velocity data of the drilled well and the pre-extracted seismic attribute data at the seismic interpretation layer of the target layer, and extract the seismic attributes whose seismic attribute correlation coefficient in the correlation curve exceeds a preset second correlation coefficient threshold as the preferred target layer related seismic attributes, wherein the seismic attributes include attributes reflecting structure and lithology; The velocity body construction module is used to use the time-depth relationship of the drilled well as the reference control point and the seismic interpretation level as the constraint. For each seismic interpretation level, the velocity between wells is fitted according to the control weights of the drilled well velocity and the seismic attributes related to the target layer in the pre-established time structure model of the target layer, and the velocity distribution data of each seismic interpretation level is obtained; the control weight is set based on the seismic attribute correlation coefficient; According to the velocity distribution data of each seismic interpretation layer, the layer velocity body of the target layer is obtained; And it is used to establish an average velocity body from the surface to the target layer based on the layer velocity body of the target layer, so as to obtain the seismic velocity body of the target area.

10. A computer storage medium, characterized in that: The computer storage medium stores computer executable instructions, and when the computer executable instructions are executed by a processor, the method for constructing a seismic velocity body according to any one of claims 1 to 8 is implemented.

11. A computer device, characterized in that: include: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the seismic velocity body construction method described in any one of claims 1 to 8 when executing the program.

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