A data acquisition and processing method and system for double-ship towing unequal-length cables

Abstract

The application discloses a data acquisition processing method and system for double-ship towed unequal-length cables, and the method comprises the following steps: the main ship is used for towing a first number of first cables and a second number of second cables to move, wherein the head end of each cable is fixed at equal intervals by an inter-cable expansion rope, adjacent first cables form a first cable array, adjacent second cables form a second cable array, the first cable array is arranged on the same side of the turning direction of the main ship, and the second cable array is arranged on the opposite side of the turning direction of the main ship; the length of the first cable is greater than that of the second cable; in the moving process, the seismic source waves emitted alternately by the seismic sources towed by the main ship and the auxiliary ship are used for collecting the seismic reflection waves reflected by different underwater media based on the geophones arranged on the cables to obtain seismic data; and the seismic data is subjected to quality control processing. The scheme can make full use of the length conditions of different cables in the unequal-length cables, and can obtain conventional data and long offset distance data.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of marine oil exploration, and particularly relates to a data acquisition and processing method and system for double-ship towed unequal-length cables. BACKGROUND

[0002] Towed cable seismic acquisition is a widely used technology in marine oil exploration, which specifically collects seismic data through cables towed under the sea surface. These data help determine the location and size of oil and gas reservoirs. Traditional towed cable acquisition uses equal-length cable acquisition methods, but this acquisition method is not easy to implement long offset acquisition. At the same time, conventional towed cable long offset acquisition is often limited by the lack of cable equipment, ship towing capacity, and acquisition cost. Existing technologies cannot obtain both conventional data required for imaging and long offset data required for full waveform inversion under limited equipment conditions. SUMMARY

[0003] The present application provides a data acquisition and processing method and system for double-ship towed unequal-length cables, which can make full use of the length of different cables in unequal-length cables under limited equipment conditions, and obtain both conventional data required for imaging and long offset data required for full waveform inversion.

[0004] In a first aspect, the present application provides a data acquisition and processing method for double-ship towed unequal-length cables, which comprises:

[0005] The first number of first cables and the second number of second cables are towed by the main ship to travel, wherein the head end of each first cable and each second cable is fixed at equal intervals by an inter-cable expansion rope, adjacent first cables are arranged to form a first cable array, and adjacent second cables are arranged to form a second cable array. The first cable array is arranged on the same side of the main ship turning direction, and the second cable array is arranged on the opposite side of the main ship turning direction. The length of the first cable is greater than the length of the second cable.

[0006] During the traveling process, the seismic source waves emitted alternately by the seismic sources towed by the main ship and the auxiliary ship are used to collect the seismic reflection waves reflected by different media under the sea based on the geophones arranged on the cables towed by the main ship, to obtain seismic data.

[0007] The seismic data is subjected to quality control processing, which is used to determine whether the positioning and coverage of the collected seismic data meet the preset conditions.

[0008] In a second aspect, the present application further provides a data acquisition and processing system for double-ship towed unequal-length cables, which comprises a main ship, an auxiliary ship, cables towed by the main ship, and a data processing module, wherein:

[0009] a main ship for towing a cable for traveling; the main ship also towing a seismic source;

[0010] an auxiliary ship for towing a seismic source for providing auxiliary seismic source;

[0011] the seismic sources towed by the main ship and the auxiliary ship are alternately emitted to the sea bottom;

[0012] the cable towed by the main ship includes a first number of long cables and a second number of short cables; wherein the head end of each of the first cables and each of the second cables is fixed by an equal interval of an inter-cable expansion rope, adjacent first cables are arranged to form a first cable array, and adjacent second cables are arranged to form a second cable array; the first cable array is arranged on the same side of the turning direction of the main ship, and the second cable array is arranged on the opposite side of the turning direction of the main ship; the length of the first cable is greater than the length of the second cable;

[0013] a geophone is arranged on the cable, and the geophone is used to collect seismic reflection waves reflected by different media under the sea to obtain seismic data;

[0014] a data processing module is used to perform quality control processing on the seismic data, and the quality control processing is used to determine whether the positioning and coverage of the collected seismic data meet a preset condition; the data processing module is arranged on the main ship.

[0015] The technical scheme provided by the application is that a main ship drags a first number of first cables and a second number of second cables to travel, wherein the head end of each first cable and each second cable is fixed at equal intervals by an inter-cable expansion rope, adjacent first cables are arranged to form a first cable array, adjacent second cables are arranged to form a second cable array, the first cable array is arranged on the same side of the turning direction of the main ship, and the second cable array is arranged on the opposite side of the turning direction of the main ship; the length of the first cable is greater than the length of the second cable; in the process of traveling, the seismic source waves emitted alternately by the seismic sources dragged by the main ship and the auxiliary ship are used to collect the seismic reflection waves reflected by different media under the sea based on the detectors arranged on the cables to obtain seismic data; and the seismic data is subjected to quality control processing to determine whether the positioning and coverage of the collected seismic data meet preset conditions. By using the scheme of the application, the longer cable can collect long offset distance data required for full waveform inversion, and the other cables can collect conventional data required for imaging, so that the length of different cables in the unequal length cables can be fully utilized under the condition of limited equipment, and the conventional data required for imaging and the long offset distance data required for full waveform inversion can be obtained. Meanwhile, the auxiliary ship on one side of the cable dragged by the main ship can provide a seismic source, so that the collected conventional seismic data can be near trace data or near mid-trace data as much as possible, thereby improving the resolution and imaging quality of the data.

[0016] The above summary of the application is only a summary of the technical scheme of the application, in order to more clearly understand the technical means of the application, the content of the specification can be implemented, and in order to make the above and other purposes, characteristics and advantages of the application more obvious and easy to understand, the following specific embodiments of the application are described. BRIEF DESCRIPTION OF DRAWINGS

[0017] The above and other features, advantages, and aspects of embodiments of the application will become more apparent by referring to the following detailed description in conjunction with the accompanying drawings. Throughout the drawings, like or similar reference numerals are used to refer to like or similar elements throughout the various figures. It should be understood that the drawings are diagrammatic and schematic representation of preferred embodiments of the application, and element and features are not necessarily to scale as shown in the figures.

[0018] Figure 1 A flowchart of a data acquisition and processing method of a double-ship unequal-length cable dragging method provided by an embodiment of the application;

[0019] Figure 2 A schematic diagram of a double-ship unequal-length cable dragging method provided by an embodiment of the application;

[0020] Figure 3 A structural schematic diagram of a data acquisition and processing system of a double-ship unequal-length cable dragging method provided by an embodiment of the application. Detailed Implementation

[0021] Embodiments of the present invention will now be described in more detail with reference to the accompanying drawings. While some embodiments of the invention are shown in the drawings, it should be understood that the invention can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the invention. It should be understood that the accompanying drawings and embodiments are for illustrative purposes only and are not intended to limit the scope of protection of the invention.

[0022] It should be understood that the various steps described in the method embodiments of the present invention may be performed in different orders and / or in parallel. Furthermore, the method embodiments may include additional steps and / or omit the steps shown. The scope of the present invention is not limited in this respect.

[0023] The term "comprising" and its variations as used herein are open-ended inclusions, meaning "including but not limited to". The term "based on" means "at least partially based on". The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments". Definitions of other terms will be given in the description below.

[0024] It should be noted that the concepts of "first" and "second" mentioned in this invention are only used to distinguish different devices, modules or units, and are not used to limit the order of functions performed by these devices, modules or units or their interdependencies.

[0025] It should be noted that the terms "a" and "a plurality of" used in this invention are illustrative rather than restrictive. Those skilled in the art should understand that, unless otherwise expressly indicated in the context, they should be understood as "one or more".

[0026] The names of the messages or information exchanged between the multiple devices in the embodiments of the present invention are for illustrative purposes only and are not intended to limit the scope of these messages or information.

[0027] Figure 1 This is a flowchart illustrating a data acquisition and processing method for dual-ship towed cables of unequal lengths provided in an embodiment of the present invention. This embodiment is applicable to the acquisition of seismic wave data using towed cables, and the method can be executed by a data acquisition and processing system for dual-ship towed cables of unequal lengths. Figure 1 As shown, the data acquisition and processing method for dual-ship towed cables of unequal length according to an embodiment of the present invention may include the following process:

[0028] S110, the first number of first cables and the second number of second cables are towed by the main ship to travel, wherein the head end of each first cable and each second cable is fixed at equal intervals by an inter-cable expansion rope, adjacent first cables are arranged to form a first cable array, adjacent second cables are arranged to form a second cable array, the first cable array is arranged on the same side of the turning direction of the main ship, and the second cable array is arranged on the opposite side of the turning direction of the main ship; the length of the first cable is greater than the length of the second cable.

[0029] Exemplary, Figure 2 A schematic diagram of a double-ship towed unequal-length cable provided by an embodiment of the present application is shown in FIG. 1. Figure 2 As shown in FIG. 1, the main ship is towing first cables and second cables behind the main ship. Figure 2 In FIG. 1, the cables numbered 9-10 are first cables, and the cables numbered 1-8 are second cables. The head end of each first cable and each second cable is fixed at equal intervals by an inter-cable expansion rope. For example, the inter-cable distance during fixing can be set to 50 m, 75 m, 100 m, 150 m, 200 m, etc.

[0030] In FIG. 1, adjacent first cables are arranged to form a first cable array, and adjacent second cables are arranged to form a second cable array. Each cable in the cable array is arranged in parallel.

[0031] The first cable array is arranged on the same side of the turning direction of the main ship, and the second cable array is arranged on the opposite side of the turning direction of the main ship. The turning direction of the main ship includes turning left or turning right. The turning direction of the main ship is determined in advance before the towed cable collection operation, and the setting positions of the first cable array and the second cable array are determined accordingly. The purpose is to ensure that the first cable array is arranged on the same side of the turning direction of the main ship, and the second cable array is arranged on the opposite side of the turning direction of the main ship. That is, if the turning direction of the main ship is to the left, the first cable array is arranged on the left side in the cable area towed by the main ship; if the turning direction of the main ship is to the right, the first cable array is arranged on the right side in the cable area towed by the main ship. Figure 2 As shown in FIG. 1, the first cable array is arranged on the left side in the cable area towed by the main ship.

[0032] It should be noted that, in the embodiment of the present application, the first cable array is arranged on the same side of the turning direction of the main ship, and the second cable array is arranged on the opposite side of the turning direction of the main ship. This can effectively ensure that, during the turning process of the main ship towing the cables, the two adjacent cables in the first cable array and the second cable array will not be entangled due to inconsistent swinging rates, and the safety of the towed cable collection operation is ensured as much as possible. That is, the entanglement between the cables numbered 8 and 9 in FIG. 1 can be avoided. Figure 2 In actual operation, when the main ship needs to turn, it is preferable to turn with a large radius as much as possible.

[0033] Specifically, the first quantity and the second quantity can be set based on the complexity of the actual target area to be explored, but are also limited by the total number of cables that the main ship can tow.

[0034] As an optional but non-limiting implementation, the first cables are at least two, and the first quantity of the first cables does not exceed forty percent of the total number of cables that the main ship can tow. For example, the main ship can tow 2 first cables and 8 second cables; for another example, the main ship can tow 4 first cables and 6 second cables, etc.

[0035] The length of the first cable is greater than the length of the second cable, and the lengths of the two types of cables are not equal. The lengths of the first cables are equal, and the lengths of the second cables are equal. Specifically, the cable length is related to the depth of the target layer, which is the main target formation or reservoir of the exploration operation. The length of the first cable is preferably set to be 3 times the depth of the main target layer, and the length of the second cable is preferably set to be more than 1 times the depth of the deepest target layer.

[0036] As an optional but non-limiting implementation, the auxiliary ship is arranged on the outside of the second cable array and away from one side of the first cable array; the first mapping position point of the position of the auxiliary ship on the reference line is less than a preset difference value from the second mapping position point of the midpoint of the second cable on the reference line; the reference line is a straight line in the extension direction of the cables; the vertical distance between the auxiliary ship and the main ship central axis is an integer multiple of half the width of the cables towed by the main ship, and the width of the cables towed by the main ship is the total number of cables towed by the main ship multiplied by the cable spacing; the main ship central axis is the central axis of the main ship in the extension direction of the cables.

[0037] Specifically, the auxiliary ship is arranged on the outside of the second cable array and away from one side of the first cable array. Figure 2 As shown in the figure, when the first cable array is arranged on the left side of the cable area towed by the main ship, the auxiliary ship is arranged on the right side of the second cable array. Correspondingly, if the first cable array is arranged on the right side of the cable area towed by the main ship, the auxiliary ship is arranged on the left side of the second cable array.

[0038] The first mapping position point of the position of the auxiliary ship on the reference line is less than a preset difference value from the second mapping position point of the midpoint of the second cable on the reference line; wherein the preset difference value can be determined according to actual needs, and the distance between the first mapping position point and the second mapping position point is less than the preset difference value, which means that the two points are coincident or close, which is equivalent to making the position of the auxiliary ship correspond to the midpoint position of the second cable as much as possible. The reference line is a straight line in the extension direction of the cables, and when determining the distance between the first mapping position point and the second mapping position point, it should be determined for the mapping on the same reference line.

[0039] The vertical distance between the auxiliary vessel and the centerline of the main vessel is an integer multiple of half the width of the main vessel's towing cable, where the towing cable width is the total number of towing cables multiplied by the cable spacing. For example, the integer multiple can be set to 1, 2, or 3 times, etc. Preferably, it can be set to 2 times, that is, the vertical distance between the auxiliary vessel and the centerline of the main vessel is equal to the width of the main vessel's towing cable. This ensures that the auxiliary vessel is neither too close nor too far from the cable, maintaining a moderate distance.

[0040] It should be noted that the width of the main ship's towing cable is not merely the sum of the cable spacing between all the cables; there is also an additional half-spacing section beyond the outermost two cables. For example, with... Figure 2 In the case shown, for example, the width of the tow cable includes not only the nine cable spacings formed between the ten cables, but also... Figure 2 The upper side of cable No. 1 and the lower side of cable No. 10 each have a cable spacing of half. The width of the towed cable is composed of these two parts. Therefore, the width of the towed cable is the total number of towed cables of the main ship multiplied by the cable spacing.

[0041] For example, such as Figure 2 As shown, the cable spacing is D. Figure 2 In the longitudinal direction, the distance X between the auxiliary vessel and the centerline of the main vessel is twice half the width of the main vessel's towing cable; that is, distance X is equal to the width of the main vessel's towing cable. Figure 2 In the transverse direction, the position of the auxiliary vessel is basically aligned with the midpoint of the second cable; the centerline of the main vessel is the centerline of the main vessel in the direction of cable extension.

[0042] It should be noted that the position and distance settings for the auxiliary ship in this embodiment of the invention can ensure that the seismic data on the source wave of the auxiliary ship collected by the detectors on each cable are as close-range or near-middle-range data as possible, thereby improving the resolution and imaging quality of the data.

[0043] As an optional but non-limiting implementation, each of the first cables is provided with a lateral bird, which is located within a reference area of ​​the first cable. The reference area is the region formed between a reference dividing point in the first cable and the tail end of the first cable. The reference dividing point is a point in the first cable that is aligned with the tail end of the second cable. At least one lateral bird is provided within the reference area of ​​the first cable, and another bird is provided before the reference area. The distance between any two adjacent lateral birds satisfies a preset spacing.

[0044] Specifically, such as Figure 2As shown, the point A in the first cable which is aligned with the tail end of the second cable is the reference demarcation point, and the area between the reference demarcation point A and the tail end of the first cable is the reference area. The transverse birds are arranged on each first cable, and at least one transverse bird is arranged in the reference area of the first cable, and one transverse bird is arranged before the reference area. Moreover, the distance between each adjacent two transverse birds satisfies a preset interval, which can be 300 meters. For example, taking the 10th cable in Figure 2 as an example, if the preset interval is 300 meters, the arrangement of the transverse birds can be: the first transverse bird is arranged at 150 meters before the point A, the second transverse bird is arranged at 150 meters after the point A, the third transverse bird is arranged at 450 meters after the point A, and the fourth transverse bird is arranged at 750 meters after the point A, and so on, until the transverse bird is arranged to the tail end of the first cable.

[0045] S120, in the process of traveling, the seismic source waves emitted alternately by the seismic sources towed by the main ship and the auxiliary ship are used to collect the seismic reflection waves reflected by different media under the sea based on the geophones arranged on the main ship towed cable to obtain seismic data.

[0046] Wherein, the main ship and the auxiliary ship each tow a seismic source, the seismic source towed by the main ship is located in the area between the main ship and the spreader, as shown in Figure 2 , the red dot in Figure 3 is the towed seismic source. In the process of traveling, the seismic source waves emitted alternately by the seismic sources towed by the main ship and the auxiliary ship are used to collect the seismic reflection waves reflected by different media under the sea based on the geophones arranged on the main ship towed cable to obtain seismic data.

[0047] In the process of traveling, only seismic data acquisition is performed in the straight driving part, and no seismic data acquisition is performed in the turning driving part.

[0048] S130, quality control processing is performed on the seismic data, and the quality control processing is used to judge whether the positioning and coverage of the collected seismic data satisfy a preset condition.

[0049] After the seismic data is collected, quality control processing is performed on the seismic data, and the quality control processing is used to judge whether the positioning and coverage of the collected seismic data satisfy a preset condition. The preset condition includes whether the seismic data has an abnormal condition.

[0050] As an optional but not limited implementation manner, the quality control processing on the seismic data can include the following steps A1-A3:

[0051] Step A1: collecting position data based on the positioning navigation devices arranged on each positioning node of the main ship towed cable to obtain navigation data.

[0052] The positioning and navigation device includes a compass bird, an acoustic bird, and a satellite positioning system device. The positioning and navigation device is arranged at each positioning node on each cable towed by the main ship, and can collect relevant position data. The navigation data can be obtained by calculating the position data via the integrated navigation system. The navigation data is a collection of position information of various devices, and includes position information of the seismic source, position information of each geophone, position information of the main ship, position information of the auxiliary ship, and the like.

[0053] Step A2: Real-time navigation bin positioning quality control of the navigation data based on the five-section method and seismic data processing software. The navigation bin corresponds to the navigation data.

[0054] The five-section method is set for the unequal-length cable towed by the main ship in the embodiment of the present application. The seismic data processing software can be used to process the navigation data to generate data processing bins corresponding to the navigation bins. The navigation bin corresponds to the navigation data. Five interval sections can be obtained by means of the five-section method, and a set of data processing bins consistent with the navigation system offset distance range can be drawn according to the five interval sections. The coverage of the navigation bins and the data processing bins can be verified with each other to determine the coverage of each position point of the navigation data, so as to realize real-time navigation bin positioning quality control of the navigation data.

[0055] Step A3: Obtain the data processing bins corresponding to the navigation bins obtained in the navigation bin positioning quality control process, and perform seismic data depth quality control on the seismic data based on the navigation bins and the data processing bins.

[0056] After the navigation bin positioning quality control process is completed, the data processing bins corresponding to the navigation bins obtained in the navigation bin positioning quality control process can be obtained, that is, the navigation bins and the data processing bins can be obtained. Then, the two types of bins can be used to perform seismic data depth quality control on the seismic data to determine the abnormality of the seismic data.

[0057] It should be noted that in the embodiment of the present application, two links of quality control processing are performed on the obtained navigation data and seismic data, respectively, which can ensure the accuracy of the collected data and facilitate the subsequent use and processing of the data.

[0058] As an optional but non-limiting implementation manner, real-time navigation bin positioning quality control of the navigation data based on the five-section method and seismic data processing software, and obtaining the data processing bins corresponding to the navigation bins, can include the following steps B1-B4:

[0059] Step B1: divide the same length part of the first cable corresponding to the second cable into four segments, divide the part of the first cable exceeding the length of the second cable into a fifth segment, and divide the second cable into four segments to divide the navigation data into five target segments.

[0060] Since the length of the first cable is greater than the length of the second cable, the lengths of the two types of cables are not equal, and when the navigation data is divided, the same length part of the first cable corresponding to the second cable can be divided into four segments, and the part of the first cable exceeding the length of the second cable can be divided into a fifth segment. At the same time, the second cable is also divided into four segments, so that the navigation data is divided into five target segments.

[0061] For example, the length of the first cable is L1, and the length of the second cable is L2 (L1 is greater than L2). The same length part of the first cable corresponding to the second cable is divided into four segments, that is, 0-25% of L1 corresponding to L2, 26%-50% of L2, 51%-75% of L2, and 76%-100% of L2 are obtained. The part of L1-L2 in L1 is divided into a fifth segment. At the same time, the second cable is also directly divided into four segments, so that the first four segments of the first cable and the four segments after division are also corresponding to each other. Thus, the following five target segments are obtained: 0-25% of L2, 26%-50% of L2, 51%-75% of L2, 76%-100% of L2, and L1-L2. The five target segments represent the division of the offset range, which corresponds to the five segments of the double-ship towed unequal-length cable mode set in the embodiment of the present application.

[0062] Step B2: based on the seismic data processing software, draw and process the navigation data corresponding to the five target segments to obtain data processing bins corresponding to the navigation bins.

[0063] After obtaining the five target segments, the seismic data processing software can be used to draw and process the navigation data according to the interval segments corresponding to the five target segments to draw bins consistent with the navigation system offset range, that is, to obtain data processing bins corresponding to the navigation bins.

[0064] Step B3: cross and compare the navigation bins and the data processing bins to determine the cross and comparison result between the bins.

[0065] After the data processing bins are drawn, the navigation bins and the data processing bins can be cross-compared to determine the cross-comparison result between the bins. The coverage of the navigation bins and the data processing bins is verified to determine the coverage of the navigation data at each position point, so as to realize real-time navigation bin positioning quality control of the navigation data.

[0066] Step B4: If the cross comparison result is less than the preset threshold, the navigation data is normal.

[0067] The preset threshold can be set based on actual requirements. If the cross comparison result is less than the preset threshold, it indicates that the coverage between the navigation surface element and the data processing surface element is good, and the navigation data at each position point has been basically covered, and the obtained navigation data is normal.

[0068] As an optional but non-limiting implementation, the cross comparison between the navigation surface element and the data processing surface element includes: comparing the shape information, color label information and range information between each navigation surface element and the corresponding data processing surface element.

[0069] Specifically, when cross comparison is performed, the shape information, color label information and range information between each navigation surface element and the corresponding data processing surface element are compared. For example, whether the shape information in the two surface elements is consistent, whether the color label information is consistent, etc. The color label information is used to reflect the attribute information of the data, and different color labels represent different numerical values. In the process of comparing the color label information, whether the numerical values corresponding to the color labels are consistent can be compared.

[0070] As an optional but non-limiting implementation, the seismic data depth quality control based on the navigation surface element and the data processing surface element can include the following steps C1-C5:

[0071] Step C1: Determine the first navigation data related to the seismic data in the navigation data.

[0072] Specifically, for the obtained navigation data, only the navigation data related to the seismic data is selected as the first navigation data.

[0073] Step C2: Fuse and match the collected seismic data and the first navigation data to obtain first seismic data.

[0074] By fusing and matching the collected seismic data and the first navigation data, the corresponding position information can be assigned to the seismic data, and the obtained first seismic data can reflect the detailed seismic data at each position.

[0075] Step C3: Based on the corresponding interval segments of the five target segments, the first seismic data is segmented and selected, and the selected first seismic data is processed for three-dimensional data processing, to obtain the seismic data volume corresponding to the five target segments.

[0076] After obtaining the first seismic data, the corresponding first seismic data can be selected according to the five target segments corresponding to the respective interval segments, that is, the first seismic data corresponding to the five segments of 0-25% of L2, 26%-50% of L2, 51%-75% of L2, 76%-100% of L2 and L1-L2 are selected. Then, the selected first seismic data of each segment is processed respectively to obtain the seismic data volume corresponding to the five target segments. The seismic data volume reflects a three-dimensional seismic data set.

[0077] Step C4: Data volume time slices corresponding to the five target segments are made to obtain time slices corresponding to the five target segments.

[0078] The data volume time slice is a horizontal section extracted from the seismic data volume. After obtaining the seismic data volume corresponding to the five target segments, data volume time slices can be made for these seismic data volumes to obtain time slices corresponding to the five target segments.

[0079] Step C5: The time slices corresponding to each target segment are compared with the navigation face elements and data processing face elements corresponding to each target segment, respectively, to determine the abnormal situation of the seismic data.

[0080] Specifically, for the time slices corresponding to each target segment, the time slices can be compared with the navigation face elements and data processing face elements corresponding to each target segment, respectively, to determine whether there is corresponding seismic data on each navigation face element and data processing face element, and then determine the abnormal situation of the seismic data. The abnormal situation includes the coverage, missing and misplacement of the seismic data.

[0081] As an optional but non-limiting implementation, after the quality control processing of the seismic data, the data acquisition and processing method of the double-ship towed unequal-length cable of the embodiment of the application can further include the following steps D1-D3:

[0082] Step D1: Ray integral migration is performed on the collected seismic data to obtain the migration profile of the collection work area.

[0083] Ray integral migration is performed on the collected seismic data to obtain the migration profile of the collection work area. Specifically, in the case of a velocity model, the Ray integral migration can be expressed as the following integral formula:

[0084]

[0085] where i(η) represents the migration profile, η is the profile sample coordinate; ξ is a shot-receiver pair (s, r) coordinate, s is the shot point, and r is the receiver point; d(ξ, t) is the acquired seismic record, t is the time; ds represents the integral surface element; τ represents the sum of the travel times of the ray from the shot point to the imaging point and from the imaging point to the receiver point, which can be obtained by the geometric relationship of the propagation path. m (ξ,η) is the weight factor of Kirchhoff integral migration.

[0086] Specifically, the weight factor of Kirchhoff integral migration can be calculated by the following formula:

[0087]

[0088] where v(η) is the velocity at the imaging point; θ is the incidence angle; R(η, r) is the path length from the profile sample to the receiver point.

[0089] Step D2: converting the migration profile into a seismic record based on the reverse migration technology.

[0090] Specifically, the reverse migration can be used to convert the migration profile of the acquisition work area into a seismic record. Specifically, the following integral formula of Rayleigh reverse migration can be used for conversion:

[0091]

[0092] where w d (η,ξ) is the weight factor of Rayleigh integral; L0 is the propagation distance of the incident ray, L is the propagation distance of the diffracted ray; θ0 is the angle between the incident ray and the stratum, θ is the angle between the incident ray and the stratum; v(η) is the velocity at the imaging point, ξ is a shot-receiver pair (s, r) coordinate; i(η) is the depth migration profile; η represents the coordinate of the sample in the imaging profile; ds is the integral surface element. D(ξ, t) represents the seismic record of the entire work area established by reverse migration.

[0093] Step D3: data interpolation is performed on the area after the tail of the second cable to complete the seismic record of the area after the tail of the second cable.

[0094] After the seismic record of the entire work area is converted, data interpolation can be performed on the area after the tail of the second cable to complete the seismic record of the area after the tail of the second cable, that is, to complete the area after the tail of the second cable which is not aligned with the tail of the first cable.

[0095] The technical scheme provided by the embodiment of the present application can make the longer cable collect long offset distance data required by full waveform inversion, and the other cables can collect conventional data required by imaging, so that the length of different cables in the unequal length cables can be fully utilized under the condition of limited equipment, and the conventional data required by imaging and the long offset distance data required by full waveform inversion can be obtained. Meanwhile, the auxiliary ship capable of providing a seismic source is arranged on one side of the cable towed by the main ship, so that the collected conventional seismic data can be near trace data or near mid trace data as much as possible, thereby improving the resolution and imaging quality of the data.

[0096] Figure 3 The structure diagram of the data acquisition and processing system of the double-ship towed unequal length cable provided by the embodiment of the present application is applicable to the case of towed cable acquisition of seismic wave data, and the data acquisition and processing system of the double-ship towed unequal length cable can execute the data acquisition and processing method of the double-ship towed unequal length cable. As shown in the figure, ​ The data acquisition and processing system of the double-ship towed unequal length cable of the embodiment of the present application includes a main ship 310, an auxiliary ship 320, a cable 330 towed by the main ship, and a data processing module 340. Among them:

[0097] The main ship 310 is used for towing the cable to travel; the main ship also tows a seismic source;

[0098] The auxiliary ship 320 tows a seismic source and is used for providing an auxiliary seismic source;

[0099] The seismic waves emitted alternately by the seismic sources towed by the main ship and the auxiliary ship;

[0100] The cable 330 towed by the main ship includes a first number of long cables and a second number of short cables; wherein the head end of each first cable and each second cable is fixed at equal intervals by an inter-cable expansion rope, adjacent first cables are arranged to form a first cable array, adjacent second cables are arranged to form a second cable array, the first cable array is arranged on the same side of the turning direction of the main ship, and the second cable array is arranged on the opposite side of the turning direction of the main ship; the length of the first cable is greater than the length of the second cable;

[0101] The cable is configured with a geophone, and the geophone is used for collecting seismic reflection waves reflected by different media under the sea to obtain seismic data;

[0102] The data processing module 340 is used for quality control processing of the seismic data, and the quality control processing is used for judging whether the positioning and coverage of the collected seismic data meet the preset conditions; the data processing module is arranged on the main ship.

[0103] As an optional but non-limiting implementation, the auxiliary ship 320 is arranged outside the second cable array and away from one side of the first cable array; a first mapping position point of the position point of the auxiliary ship is mapped on a reference line, and a distance between the first mapping position point and a second mapping position point of a midpoint of the second cable mapped on the reference line is less than a preset difference value; the reference line is a straight line in the cable extension direction; a vertical distance between the auxiliary ship and a central axis of the main ship is an integer multiple of one half of a main ship towed cable width, and the towed cable width is a total number of the main ship towed cables multiplied by a cable spacing; the central axis of the main ship is a central axis of the main ship in the cable extension direction.

[0104] As an optional but non-limiting implementation, the first cable is at least two, and a first number of the first cable is not more than forty percent of a total number of main ship towed cables.

[0105] As an optional but non-limiting implementation, a transverse bird is arranged on each of the first cables, and the transverse bird is arranged in a reference region of the first cable, the reference region being a region formed between a reference demarcation point in the first cable and a tail end of the first cable, and the reference demarcation point being a point in the first cable at a position aligned with the tail end of the second cable.

[0106] The transverse bird is arranged at least once in the reference region of the first cable, and is further arranged once before the reference region; a distance between each two adjacent transverse birds satisfies a preset spacing.

[0107] As an optional but non-limiting implementation, the quality control processing of the seismic data includes:

[0108] Position data is acquired based on a positioning navigation device configured on each positioning node of the main ship towed cable, and navigation data is obtained;

[0109] Real-time navigation bin positioning quality control is performed on the navigation data based on a five-segment method and seismic data processing software; the navigation bin is a bin corresponding to the navigation data;

[0110] Data processing bins corresponding to the navigation bins obtained in the navigation bin positioning quality control process are acquired, and seismic data depth quality control is performed on the seismic data based on the navigation bins and the data processing bins.

[0111] As an optional but non-limiting implementation, the real-time navigation bin positioning quality control performed on the navigation data based on the five-segment method and the seismic data processing software includes:

[0112] The part of the first cable corresponding to the same length of the second cable is divided into four parts, the part of the first cable exceeding the length of the second cable is divided into a fifth part, and the second cable is divided into four parts, so as to divide the navigation data into five target segments;

[0113] The navigation data corresponding to the five target segments is processed based on a seismic data processing software to obtain data processing bins corresponding to navigation bins;

[0114] The navigation bins and the data processing bins are cross-compared to determine the cross-comparison result between the bins;

[0115] If the cross-comparison result is less than a preset threshold, the navigation data is normal.

[0116] As an optional but non-limiting implementation, the seismic data depth quality control of the seismic data based on the navigation bins and the data processing bins comprises:

[0117] The first navigation data related to the seismic data in the navigation data is determined;

[0118] The collected seismic data and the first navigation data are fused and matched to obtain first seismic data;

[0119] The first seismic data is selected and segmented based on each interval segment corresponding to the five target segments, and each segmented first seismic data is processed to obtain a seismic data volume corresponding to the five target segments;

[0120] The seismic data volume corresponding to the five target segments is processed to obtain a time slice corresponding to the five target segments;

[0121] The time slice corresponding to each target segment is compared with the navigation bins and the data processing bins corresponding to each target segment to determine the abnormal condition of the seismic data.

[0122] As an optional but non-limiting implementation, the cross-comparison of the navigation bins and the data processing bins comprises:

[0123] The shape information, color label information and range information between each navigation bin and the corresponding data processing bin are compared.

[0124] As an optional but non-limiting implementation, after the quality control processing of the seismic data, the data acquisition and processing system of the double-ship towed unequal-length cable further comprises:

[0125] The offset profile determination module is configured to perform Rayleigh integral migration on the collected seismic data to obtain an offset profile of the working area;

[0126] The seismic record determination module is configured to convert the offset profile into a seismic record based on the de-migration technology.

[0127] The seismic record completion module is configured to perform data interpolation on the area after the second cable tail to complete the seismic record of the area after the second cable tail.

[0128] The technical scheme provided by the embodiment of the present application can make the longer cable collect long-offset data required by full waveform inversion, and the other cables can collect conventional data required for imaging, so that the length of different cables in the unequal-length cables can be fully utilized in the case of limited equipment, and the conventional data required for imaging and the long-offset data required for full waveform inversion can be obtained. At the same time, by arranging an auxiliary ship capable of providing a seismic source on one side of the main ship towing the cable, the collected conventional seismic data can be made as near trace data or near mid-trace data as possible, so as to improve the resolution and imaging quality of the data.

[0129] The technical scheme provided by the present application can be used to execute the data acquisition and processing method of the double-ship towing unequal-length cable, and has the corresponding function modules and beneficial effects of executing the data acquisition and processing method of the double-ship towing unequal-length cable.

[0130] The above description is only the preferred embodiment of the present application and the explanation of the applied technical principles. Those skilled in the art should understand that the disclosed range in the present application is not limited to the technical scheme formed by the specific combination of the above technical features, and also covers other technical schemes formed by any combination of the above technical features or equivalent features without departing from the disclosed concept. For example, the technical scheme formed by replacing the above features with the technical features disclosed in the present application (but not limited to) having similar functions.

[0131] In addition, although each operation is described in a particular order, this should not be understood as requiring the operations to be performed in the specific order shown or in a sequential order. In certain circumstances, multi-tasking and parallel processing can be advantageous. Similarly, although the above discussion contains many specific implementation details, these should not be construed as limiting the scope of the application. Certain features described in the context of separate embodiments can also be combined in a single embodiment. Conversely, various features described in the context of a single embodiment can also be implemented separately or in any suitable sub-combination.

[0132] Although the subject matter has been described in language specific to structural features and / or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims

1. A data acquisition and processing method for dual-ship towed cables of unequal length, characterized in that, The method includes: The main vessel travels by towing a first number of first cables and a second number of second cables. The head ends of each first cable and each second cable are fixed at equal intervals by cable extension ropes. Adjacent first cables are arranged to form a first cable array, and adjacent second cables are arranged to form a second cable array. The first cable array is located on the same side of the main vessel's turning direction, and the second cable array is located on the opposite side of the main vessel's turning direction. The length of the first cable is greater than the length of the second cable. During the journey, the seismic waves emitted alternately by the seismic sources towed by the main ship and the auxiliary ship are collected by the geophones configured on the tow cable of the main ship to collect the seismic reflected waves reflected by different media underwater, and the seismic data is obtained. The seismic data is subjected to quality control processing, which is used to determine whether the location and coverage of the acquired seismic data meet preset conditions. The auxiliary vessel is located outside the second cable array and on the side away from the first cable array; The distance between the position point of the auxiliary vessel mapped to the first mapped position point on the reference line and the midpoint of the second cable mapped to the second mapped position point on the reference line is less than a preset difference; the reference line is a straight line in the direction of cable extension; The vertical distance between the auxiliary vessel and the centerline of the main vessel is an integer multiple of half the width of the main vessel's towing cable, and the width of the towing cable is the total number of towing cables of the main vessel multiplied by the cable spacing; the centerline of the main vessel is the centerline of the main vessel in the direction of cable extension. Each of the first cables is provided with a transverse bird, which is located within a reference area of ​​the first cable. The reference area is the area formed between a reference dividing point in the first cable and the tail end of the first cable. The reference dividing point is a point in the first cable that is aligned with the tail end of the second cable. At least one lateral bird is provided in the reference area of ​​the first cable, and another is provided before the reference area; the distance between any two adjacent lateral birds satisfies a preset spacing. The quality control processing of the seismic data includes: Position data is obtained by collecting position data from positioning and navigation devices configured at each positioning node on the main ship's towing cable; The navigation data is subjected to real-time navigation surface positioning quality control based on the five-segment division method and seismic data processing software; the navigation surface is the surface corresponding to the navigation data. Obtain the data processing surface corresponding to the navigation surface obtained during the navigation surface positioning quality control process, and perform seismic data depth quality control on the seismic data based on the navigation surface and the data processing surface.

2. The method according to claim 1, characterized in that, The first cable shall be at least two, and the first number of the first cables shall not exceed 40% of the total number of cables towed by the main vessel.

3. The method according to claim 1, characterized in that, The real-time navigation surface positioning quality control of the navigation data based on the five-segment division method and seismic data processing software includes: The portion of the first cable that corresponds to the same length as the second cable is divided into four equal segments, the portion of the first cable that exceeds the length of the second cable is divided into a fifth segment, and the second cable is also divided into four equal segments, so that the navigation data is divided into five target segments. Based on the earthquake data processing software, the navigation data corresponding to the five target segments are plotted and processed to obtain the data processing elements corresponding to the navigation elements. The navigation surface element and the data processing surface element are cross-compared to determine the cross-comparison result between the two surface elements. If the cross-comparison result is less than a preset threshold, then the navigation data is normal.

4. The method according to claim 3, characterized in that, The process of performing seismic data depth quality control on the seismic data based on the navigation surface element and the data processing surface element includes: Identify the first navigation data in the navigation data that is related to the seismic data; The collected seismic data is fused and matched with the first navigation data to obtain the first seismic data; Based on the intervals corresponding to the five target segments, the first seismic data is segmented accordingly, and the selected segments of the first seismic data are processed in three dimensions to obtain the seismic data volume corresponding to the five target segments. Time slices of seismic data volumes corresponding to the five target segments are generated to obtain time slices corresponding to the five target segments. The time slices corresponding to each target segment are compared with the corresponding navigation elements and data processing elements of each target segment to determine the anomalies in the seismic data.

5. The method according to claim 3, characterized in that, The step of cross-comparing the navigation surface element and the data processing surface element includes: Compare the shape information, color mark information, and range information between each navigation surface element and its corresponding data processing surface element.

6. The method according to claim 1, characterized in that, After performing quality control processing on the seismic data, the method further includes: Rayleigh integral migration was performed on the acquired seismic data to obtain the migration profile of the acquisition area; The migration profile is converted into a seismic record based on the inverse migration technique; Data interpolation was performed on the area following the tail of the second cable to complete the seismic record for that area.

7. A data acquisition and processing system for dual-ship towed cables of unequal length, characterized in that, The system includes a main vessel, an auxiliary vessel, cables towed by the main vessel, and a data processing module, wherein: The main vessel is used to tow cables for movement; the main vessel also tows a seismic source. Auxiliary vessel, towed with a seismic source, is used to provide an auxiliary seismic source; The seismic waves towed by the main ship and the auxiliary ship are alternately emitted into the sea. The cables towed by the main vessel include a first number of first cables and a second number of second cables; wherein the head ends of each first cable and each second cable are fixed at equal intervals by cable extension ropes, adjacent first cables are arranged to form a first cable array, and adjacent second cables are arranged to form a second cable array, the first cable array is located on the same side of the main vessel's turning direction, and the second cable array is located on the opposite side of the main vessel's turning direction; the length of the first cable is greater than the length of the second cable. The cable is equipped with a detector, which is used to collect seismic reflected waves reflected by different media underwater to obtain seismic data. The data processing module is used to perform quality control processing on the seismic data. The quality control processing is used to determine whether the location and coverage of the acquired seismic data meet preset conditions. The data processing module is installed on the main ship. The auxiliary vessel is positioned outside the second cable array and away from the first cable array; the position point of the auxiliary vessel is mapped to a first mapped position point on a reference line, and the distance between the auxiliary vessel and the midpoint of the second cable mapped to a second mapped position point on the reference line is less than a preset difference; the reference line is a straight line in the cable extension direction; the vertical distance between the auxiliary vessel and the centerline of the main vessel is an integer multiple of half the width of the towed cable of the main vessel, and the width of the towed cable is the total number of towed cables of the main vessel multiplied by the cable spacing; the centerline of the main vessel is the centerline of the main vessel in the cable extension direction. Each of the first cables is provided with a transverse bird, which is located within a reference area of ​​the first cable. The reference area is the area formed between a reference dividing point in the first cable and the tail end of the first cable. The reference dividing point is a point in the first cable that is aligned with the tail end of the second cable. At least one lateral bird is provided in the reference area of ​​the first cable, and another is provided before the reference area; the distance between any two adjacent lateral birds satisfies a preset spacing. The quality control processing of the seismic data includes: Position data is obtained by collecting position data from positioning and navigation devices configured at each positioning node on the main ship's towing cable; The navigation data is subjected to real-time navigation surface positioning quality control based on the five-segment division method and seismic data processing software; the navigation surface is the surface corresponding to the navigation data. Obtain the data processing surface corresponding to the navigation surface obtained during the navigation surface positioning quality control process, and perform seismic data depth quality control on the seismic data based on the navigation surface and the data processing surface.

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