Data acquisition and processing method and system for towing unequal-length cables by double boats

Abstract

The invention discloses a data acquisition and processing method and system for towing unequal-length cables by double boats, and the method comprises the steps: towing a first number of first cables and a second number of second cables to advance through a main boat, and enabling the head end of each cable to be fixed at equal intervals through an inter-cable extension rope, the adjacent first cables form a first cable array, the adjacent second cables form a second cable array, the first cable array is arranged on the same side of the U-turn direction of the main ship, and the second cable array is arranged on the opposite side of the U-turn direction of the main ship; the first cable is longer than the second cable; in the advancing process, seismic source waves are alternately emitted through seismic sources towed by the main ship and the auxiliary ship, seismic reflection waves reflected by different media under the sea are collected based on a detector configured on a cable, and seismic data are obtained; and performing quality control processing on the seismic data. According to the scheme, the length conditions of different cables in the unequal-length cables can be fully utilized, and conventional data and long-offset data are obtained at the same time.

Description

Technical Field

[0001] The invention relates to the technical field of offshore oil exploration, and in particular to a data acquisition and processing method and system for double-ship towing cables of unequal lengths. Background Art

[0002] Towed cable seismic acquisition is a technology widely used in offshore oil exploration. It collects seismic data by towing cables under the sea surface. These data help determine the location and size of oil and gas reservoirs. Traditional towed cable acquisition uses equal-length cables, but this acquisition method is not easy to achieve long-offset acquisition. At the same time, conventional towed cable large-offset acquisition methods are often limited by insufficient cable equipment, ship towing capacity, acquisition costs, and other issues. Existing technologies cannot take into account both conventional data for imaging requirements and long-offset data required for full waveform inversion with limited equipment. Summary of the invention

[0003] The present invention provides a data acquisition and processing method and system for dual-ship towing unequal-length cables, which can make full use of the lengths of different cables in the unequal-length cables under the condition of limited equipment, and take into account both the conventional data required for imaging and the long-offset data required for full waveform inversion.

[0004] In a first aspect, the present invention provides a data collection and processing method for two ships towing cables of unequal lengths, the method comprising:

[0005] The main ship tows a first number of first cables and a second number of second cables for travel, wherein the head ends of each of the first cables and each of the second cables 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 arranged on the same side of the main ship's turning direction, and the second cable array is arranged on the opposite side of the main ship's turning direction; the length of the first cable is greater than the length of the second cable;

[0006] During the journey, the seismic source waves towed by the main ship and the auxiliary ship are alternately emitted to the seabed. The seismic reflection waves reflected by different underwater media are collected by the detectors configured on the towing cable of the main ship to obtain seismic data.

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

[0008] In a second aspect, the present invention further provides a data acquisition and processing system for two ships towing cables of unequal lengths, the system comprising a main ship, an auxiliary ship, a cable towed by the main ship, and a data processing module, wherein:

[0009] A main ship, used for towing the cable for traveling; the main ship also tows a seismic source;

[0010] Auxiliary ship, with a towed seismic source, used to provide auxiliary seismic source;

[0011] Seismic source waves alternately emitted underwater by seismic sources towed by the main ship and the auxiliary ship;

[0012] The cables towed by the main ship include a first number of long cables and a second number of short cables; wherein the head ends of each of the first cables and each of the second cables 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 arranged on the same side of the main ship's turning direction, and the second cable array is arranged on the opposite side of the main ship's turning direction; the length of the first cable is greater than the length of the second cable;

[0013] The cable is provided with a geophone, which is used to collect seismic reflection waves reflected by different underwater media 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 preset conditions; the data processing module is arranged on the main ship.

[0015] The technical solution provided by the present invention is that a main ship tows a first number of first cables and a second number of second cables for travel, wherein the head ends of each first cable and each second cable are 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's turning direction, and the second cable array is arranged on the opposite side of the main ship's turning direction; the length of the first cable is greater than the length of the second cable; during the travel process, source waves alternately emitted to the sea by the seismic sources towed by the main ship and the auxiliary ship respectively, based on the detectors configured on the cables, seismic reflection waves reflected by different underwater media are collected to obtain seismic data; quality control processing is performed on the seismic data, and the quality control processing is used to determine whether the positioning and coverage of the collected seismic data meet preset conditions. By adopting the scheme of the present invention, the main ship tows cables of unequal lengths for data acquisition, so that the longer cables can acquire the long offset data required for full waveform inversion, and the other cables can acquire the conventional data required for imaging. This can make full use of the lengths of different cables in the unequal length cables under limited equipment conditions, and take into account both conventional data required for imaging and long offset data required for full waveform inversion. At the same time, by arranging an auxiliary ship capable of providing a source on one side of the main ship towing the cable, the conventional seismic data acquired can be as close-channel data or near-mid-channel data as possible, thereby improving the resolution and imaging quality of the data.

[0016] The above invention content is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented according to the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The above and other features, advantages and aspects of the embodiments of the present invention will become more apparent with reference to the following detailed description in conjunction with the accompanying drawings. Throughout the accompanying drawings, the same or similar reference numerals represent the same or similar elements. It should be understood that the drawings are schematic and the originals and elements are not necessarily drawn to scale.

[0018] Figure 1 A flow chart of a data collection and processing method for two ships towing cables of unequal lengths provided by an embodiment of the present invention;

[0019] Figure 2 A schematic diagram of two ships towing cables of unequal lengths provided in an embodiment of the present invention;

[0020] Figure 3 A structural schematic diagram of a data acquisition and processing system for two ships towing cables of unequal lengths provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0021] Embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although certain embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be construed as being limited to the embodiments described herein, which are instead provided for a more thorough and complete understanding of the present invention. It should be understood that the drawings and embodiments of the present invention are only for exemplary purposes and are not intended to limit the scope of protection of the present 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. In addition, 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 "including" and its variations used herein are open inclusions, i.e., "including but not limited to". The term "based on" means "based at least in part 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". The relevant definitions of other terms will be given in the following description.

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

[0025] It should be noted that the modifications of "one" and "plurality" mentioned in the present invention are illustrative rather than restrictive, and those skilled in the art should understand that, unless otherwise clearly indicated in the context, it should be understood as "one or more".

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

[0027] Figure 1 The present invention provides a flow chart of a data acquisition and processing method for a double-ship towing cable of unequal length. The present invention is applicable to the case of towing cable to collect seismic wave data. The method can be executed by a data acquisition and processing system for a double-ship towing cable of unequal length. Figure 1 As shown, the data collection and processing method for two ships towing cables of unequal lengths according to an embodiment of the present invention may include the following process:

[0028] S110. The main ship tows a first number of first cables and a second number of second cables for travel, 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 arranged on the same side of the main ship's turning direction, and the second cable array is arranged on the opposite side of the main ship's turning direction; the length of the first cable is greater than the length of the second cable.

[0029] For example, Figure 2 A schematic diagram of a double-ship towing cables of unequal lengths provided in an embodiment of the present invention, such as Figure 2 As shown, the main ship tows the first cable and the second cable behind it. Figure 2 The cables No. 9-10 are the first cables, and the cables No. 1-8 are the second cables. The head ends of the first cables and the second cables are fixed at equal intervals by cable extension ropes. For example, the cable spacing during fixing can be set to 50m, 75m, 100m, 150m, 200m, etc.

[0030] Wherein, adjacent first cables are arranged to form a first cable array, and adjacent second cables are arranged to form a second cable array, and the cables in the cable array are 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 has been predetermined before the towing cable collection operation, and the setting positions of the first cable array and the second cable array can be determined accordingly, in order 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 of the cable 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 of the cable towed by the main ship; Figure 2 What is shown in FIG. 1 is a situation where the first cable array is arranged on the left side in the cable area towed by the host ship.

[0032] It should be noted that the embodiment of the present invention sets the first cable array on the same side of the turning direction of the main ship, and sets the second cable array on the opposite side of the turning direction of the main ship, which can effectively ensure that when the main ship turns with the towed cable, the two adjacent cables in the first cable array and the second cable array will not be entangled due to inconsistent swinging speeds, thereby ensuring the safety of the towed cable collection operation as much as possible. Figure 2 The No. 8 and No. 9 cables in the cable are entangled. In the actual operation, when the main ship needs to turn around, it is best to choose a larger bend.

[0033] Specifically, the first number and the second number can be set based on the complexity of the target in the actual survey area, but are also limited by the total number of cables that can be towed by the host ship.

[0034] As an optional but non-limiting implementation, there are at least two first cables, and the first number of the first cables does not exceed 40% of the total number of cables towed by the main ship. 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 that of the second cable, and the two types of cables are not equal in length. 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 3 times the depth of the main target layer, and the length of the second cable is preferably set to more than 1 times the depth of the deepest target layer.

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

[0037] Specifically, the auxiliary ship is arranged outside the second cable array and on a side away from the first cable array. Figure 2 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 will be arranged on the right outside of the second cable array. Correspondingly, when the first cable array is arranged on the right side of the cable area towed by the main ship, the auxiliary ship will be arranged on the left outside of the second cable array.

[0038] The distance between the first mapping position point mapped on the reference line by the auxiliary ship and the second mapping position point mapped on the reference line by the midpoint of the second cable is less than a preset difference; wherein the preset difference 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, indicating 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 cable. When determining the distance between the first mapping position point and the second mapping position point, it should be determined for mapping on the same reference line.

[0039] The vertical distance between the auxiliary ship and the central axis of the main ship is an integer multiple of one half of the width of the towing cable of the main ship, wherein the width of the towing cable is the total number of towing cables of the main ship 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 ship and the central axis of the main ship is equal to the width of the towing cable of the main ship, so that the auxiliary ship is neither too close nor too far from the cable, but at a moderate distance.

[0040] It should be noted that the width of the towing cable of the main ship is not only composed of the sum of the cable spacings formed between the cables, but also includes a half cable spacing between the two outermost cables. Figure 2 For example, the width of the trailing cable includes not only the 9 cable spacings formed between the 10 cables, but also Figure 2 The upper side of cable No. 1 and the lower side of cable No. 10 are each provided with a cable spacing of one-half. The towing cable width is composed of these two parts. Therefore, the towing cable width is the total number of towing cables of the main ship multiplied by the cable spacing.

[0041] For example, Figure 2 As shown, the cable spacing is D. Figure 2 In the longitudinal direction, the distance X between the auxiliary ship and the central axis of the main ship is twice the half of the width of the towing cable of the main ship, that is, the distance X is equal to the width of the towing cable of the main ship; Figure 2 In the transverse direction, the position point of the auxiliary ship is basically aligned with the midpoint of the second cable; the central axis of the main ship is the central axis of the main ship in the direction in which the cable extends.

[0042] It should be noted that such position setting and distance setting for the auxiliary ship in the embodiment of the present invention can ensure that the seismic data about the auxiliary ship source waves collected by the detectors on each cable are near-channel data or near-mid-channel data as much as possible, thereby improving the data resolution and imaging quality.

[0043] As an optional but non-limiting implementation method, each first cable is provided with a transverse bird, which is arranged in a reference area of ​​the first cable, the reference area is an area formed between a reference demarcation point in the first cable and the tail end of the first cable, the reference demarcation point is a point in the first cable that is aligned with the tail end of the second cable; at least one transverse bird is arranged in the reference area of ​​the first cable, and another one is arranged before the reference area; the distance between each two adjacent transverse birds meets the preset spacing.

[0044] Specifically, Figure 2As shown, point A in the first cable that is aligned with the tail end of the second cable is the reference demarcation point, and the area formed between the reference demarcation point A and the tail end of the first cable is the reference area. A transverse bird is provided on each first cable, and at least one transverse bird is provided not only in the reference area of ​​the first cable, but also before the reference area. In addition, the distance between each two adjacent transverse birds meets the preset spacing, which can be 300 meters. For example, in Figure 2 Taking the setting of horizontal birds on cable No. 10 in as an example, if the preset spacing is 300 meters, the setting of the horizontal birds can be: the first horizontal bird is set 150 meters before point A, the second horizontal bird is set 150 meters after point A, the third horizontal bird is set 450 meters after point A, and the fourth horizontal bird is set 750 meters after point A, and so on, until the horizontal bird is set to the tail end of the first cable.

[0045] S120. During the travel, the seismic source waves alternately emitted to the seabed by the seismic sources towed by the main ship and the auxiliary ship are used to collect seismic reflection waves reflected by different underwater media based on the detectors configured on the towing cables of the main ship to obtain seismic data.

[0046] Among them, the main ship and the auxiliary ship each have a towed source, and the source of the towed source of the main ship is located in the area between the rear of the main ship and the extension rope between the tow ropes, such as Figure 2 As shown, Figure 2 The red dot in the middle is the seismic source of the towing. During the journey, the seismic sources towed by the main ship and the auxiliary ship respectively emit seismic source waves alternately to the seabed, and the geophones configured on the towing cable of the main ship will collect seismic reflection waves reflected by different media under the sea to obtain seismic data.

[0047] During the driving process, seismic data collection is only performed in the straight driving part, and no seismic data collection is performed in the U-turn driving part.

[0048] S130, performing quality control processing on the seismic data, the quality control processing is used to determine whether the positioning and coverage of the collected seismic data meet preset conditions.

[0049] After the seismic data is collected, it will be subjected to quality control processing, which is used to determine whether the positioning and coverage of the collected seismic data meet preset conditions. The preset conditions include: whether there are any abnormalities in the seismic data.

[0050] As an optional but non-limiting implementation, quality control processing of seismic data may include the following steps A1-A3:

[0051] Step A1: The positioning navigation equipment configured on each positioning node on the towing cable of the main ship collects position data to obtain navigation data.

[0052] Among them, the positioning and navigation equipment includes compass birds, acoustic birds and satellite positioning system equipment. Each positioning node on each cable towed by the main ship is equipped with a corresponding positioning and navigation equipment. The positioning and navigation equipment can collect relevant position data, and the obtained position data can be calculated by the integrated navigation system to obtain navigation data. Navigation data is a collection of azimuth information of various devices, including the location information of the source, the location information of each detector, the location information of the main ship, the location information of the auxiliary ship, etc.

[0053] Step A2: Based on the five-segment method and seismic data processing software, real-time navigation bin positioning quality control is performed on the navigation data; the navigation bin is the bin corresponding to the navigation data.

[0054] Among them, the five-segment division method is set for the method of towing cables of unequal lengths by the main ship set in the embodiment of the present invention. Seismic data processing software can be used to process navigation data and generate data processing facets corresponding to navigation facets. Navigation facets are facets corresponding to navigation data. With the help of the five-segment division method, five interval segments can be obtained, and a set of data processing facets consistent with the offset range of the navigation system can be drawn according to the five interval segments obtained. The coverage of navigation facets and data processing facets can be mutually verified, and the coverage of each position point of the navigation data can be determined to realize real-time navigation facet positioning quality control of the navigation data.

[0055] Step A3: Acquire 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 completing the navigation facet positioning quality control process, the data processing facets corresponding to the navigation facets obtained in the navigation facet positioning quality control process can be obtained, that is, the navigation facets and data processing facets can be obtained. These two types of facets can then be used to perform deep quality control on the seismic data to determine abnormal conditions in the seismic data.

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

[0058] As an optional but non-limiting implementation, based on the five-segment method and seismic data processing software, real-time navigation bin positioning quality control is performed on the navigation data, and data processing bins corresponding to the navigation bins are obtained, which may include the following steps B1-B4:

[0059] Step B1: Divide the portion of the first cable corresponding to the same length as the second cable into four equal sections, divide the portion of the first cable that exceeds the length of the second cable into the fifth section, and divide the second cable into four equal sections to divide the navigation data into five target sections.

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

[0061] For example, taking the length of the first cable as L1 and the length of the second cable as L2 (L1 is greater than L2), the portion of the first cable corresponding to the same length as the second cable is divided into four equal sections, that is, four sections corresponding to 0-25% of L2, 26%-50% of L2, 51%-75% of L2, and 76%-100% of L2 in L1 can be obtained; the portion of the first cable that exceeds the length of the second cable is divided into the fifth section, that is, the L1-L2 portion of L1 is divided into the fifth section. At the same time, the second cable is also directly divided into four equal sections, so that the four equal sections correspond to the first four sections of the first cable. In this way, the following five target sections can be obtained: 0-25% of L2, 26%-50% of L2, 51%-75% of L2, 76%-100% of L2, and L1-L2. These five target sections reflect the division of the offset range, which is divided into five sections corresponding to the double-ship towing unequal length cable mode set in the embodiment of the present invention.

[0062] Step B2: Based on the seismic data processing software, the navigation data corresponding to the five target segments are plotted and processed 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 segmentally draw the navigation data according to the interval segments corresponding to the five target segments to draw out the surface elements consistent with the offset range of the navigation system, and the data processing surface elements corresponding to each segment of the navigation surface elements can be obtained.

[0064] Step B3: Cross-compare the navigation facet and the data processing facet to determine the cross-compare result between the two facets.

[0065] After the data processing bins are drawn, the navigation bins and data processing bins can be cross-compared to determine the cross-comparison results between the two bins. This can verify the coverage of the navigation bins and data processing bins, determine the coverage of each location point of the navigation data, and achieve 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] Among them, the preset threshold can be set based on actual needs. If the cross-comparison result is less than the preset threshold, it means that the coverage between the navigation surface element and the data processing surface element is good, each position point of the navigation data has been basically covered, and the obtained navigation data is normal.

[0068] As an optional but non-limiting implementation, cross-comparison is performed between the navigation facets and the data processing facets, including: comparing shape information, color code information, and range information between each navigation facet and the corresponding data processing facet.

[0069] Specifically, when cross-comparison is performed, the shape information, color code information, and range information between each navigation facet and the corresponding data processing facet are compared. For example, it is determined whether the shape information in the two facets is consistent, whether the color code information is consistent, etc. Among them, the color code information is used to reflect the attribute information of the data, and the different colors of the color code represent different values. In the process of comparing the color code information, it is possible to compare whether the values ​​corresponding to the color code colors are consistent.

[0070] As an optional but non-limiting implementation, performing deep quality control of seismic data based on navigation bins and data processing bins may include the following steps C1-C5:

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

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

[0073] Step C2: fusing and matching the collected seismic data with the first navigation data to obtain first seismic data.

[0074] By fusing and matching the collected seismic data with the first navigation data, it is possible to assign corresponding position information to the seismic data, and the obtained first seismic data can reflect detailed seismic data at each location.

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

[0076] After obtaining the first seismic data, the corresponding first seismic data can be selected based on the intervals corresponding to the five target segments determined above, 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, three-dimensional data processing is performed on each selected segment of the first seismic data to obtain seismic data bodies corresponding to the five target segments. Among them, the seismic data body reflects a three-dimensional seismic data set.

[0077] Step C4: Create data volume time slices for the seismic data volumes corresponding to the five target segments 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 volumes corresponding to the five target segments, data volume time slices can be made for the seismic data volumes to obtain the time slices corresponding to the five target segments.

[0079] Step C5: Compare the time slices corresponding to each target segment with the navigation bins and data processing bins corresponding to each target segment to determine the abnormality of the seismic data.

[0080] Specifically, for the time slices corresponding to each target segment, the time slices can be compared with the navigation bins and data processing bins corresponding to each target segment to determine whether there is corresponding seismic data on each navigation bin and data processing bin, and then determine the abnormality of the seismic data. The abnormality includes the coverage, missing and misalignment of the seismic data.

[0081] As an optional but non-limiting implementation, after quality control processing of the seismic data, the data acquisition and processing method for two ships towing cables of unequal lengths according to an embodiment of the present invention may further include the following steps D1-D3:

[0082] Step D1: Perform Rayleigh integral migration on the acquired seismic data to obtain the migration profile of the acquisition area.

[0083] By performing Rayleigh integral migration on the collected seismic data, the migration profile of the acquisition area can be obtained. Specifically, in the case of a velocity model, Rayleigh integral migration can be expressed as an integral formula in the following form:

[0084]

[0085] Among them, i(η) represents the offset profile, η is the coordinate of the profile sample point; ξ is the (s,r) coordinate of a shot-to-detection pair, s is the shot point, r is the detection point; d(ξ,t) is the collected seismic record, t is the time; ds represents the integral bin; τ represents the sum of the travel time of the ray from the shot point to the imaging point and from the imaging point to the detection point, and τ can be obtained through the geometric relationship of the propagation path. m (ξ,η) is the weight factor of Kirchhoff integral shift.

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

[0087]

[0088] Where v(η) is the velocity at the imaging point; θ is the incident angle; and R(η, r) is the path length from the profile sample point to the detection point.

[0089] Step D2: Convert the migration profile into seismic records based on the DM technology.

[0090] Specifically, the migration profile of the acquisition area can be converted into a seismic record by using the back migration. Specifically, the following integral formula of Rayleigh back migration can be used for conversion:

[0091]

[0092] Among them, 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 formation, θ is the angle between the incident ray and the formation; v(η) is the velocity at the imaging point, ξ is the coordinate of a shot-to-shot pair (s,r); i(η) is the depth migration profile; η represents the coordinate of the sample point in the imaging profile; ds is the bin of integration. D(ξ,t) represents the seismic record of the entire work area established by the reverse migration.

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

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

[0095] The technical solution provided by the embodiment of the present invention is to collect data by towing cables of unequal lengths by the main ship, so that the longer cables can collect the long offset data required for full waveform inversion, and the other cables can collect the conventional data required for imaging. It can make full use of the lengths of different cables in the unequal length cables under limited equipment, and take into account both the conventional data required for imaging and the long offset data required for full waveform inversion. At the same time, by arranging an auxiliary ship capable of providing a seismic source on one side of the cable towed by the main ship, the conventional seismic data collected can be as close-channel data or near-mid-channel data as possible, thereby improving the resolution and imaging quality of the data.

[0096] Figure 3 The present invention provides a schematic diagram of a data acquisition and processing system for towing cables of unequal lengths with two ships. The present invention is applicable to the case of towing cables to collect seismic wave data. The data acquisition and processing system for towing cables of unequal lengths with two ships can execute a data acquisition and processing method for towing cables of unequal lengths with two ships. Figure 3 As shown, the data acquisition and processing system for two ships towing cables of unequal lengths according to an embodiment of the present invention 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] A main ship 310 is used to tow the cable for traveling; the main ship also tows a seismic source;

[0098] The auxiliary vessel 320 is towed with a seismic source and is used to provide an auxiliary seismic source;

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

[0100] The cables 330 towed by the main ship include a first number of long cables and a second number of short cables; wherein the head ends of each of the first cables and each of the second cables 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 arranged on the same side of the main ship's turning direction, and the second cable array is arranged on the opposite side of the main ship's turning direction; the length of the first cable is greater than the length of the second cable;

[0101] The cable is provided with a geophone, which is used to collect seismic reflection waves reflected by different underwater media to obtain seismic data;

[0102] The data processing module 340 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 preset conditions; the data processing module is set on the main ship.

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

[0104] As an optional but non-limiting implementation, the number of the first cables is at least two, and the first number of the first cables does not exceed 40 percent of the total number of towing cables of the main ship.

[0105] As an optional but non-limiting implementation, each of the first cables is provided with a transverse bird, the transverse bird being provided in a reference area of ​​the first cable, the reference area being an area formed between a reference demarcation point in the first cable and a tail end of the first cable, the reference demarcation point being a point in the first cable aligned with the tail end of the second cable;

[0106] At least one of the transverse birds is arranged in the reference area of ​​the first cable, and another one is arranged before the reference area; the distance between each two adjacent transverse birds meets the preset spacing.

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

[0108] The positioning navigation equipment configured on each positioning node on the towing cable of the main ship collects position data to obtain navigation data;

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

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

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

[0112] Divide the portion of the first cable having the same length as the second cable into four equal sections, divide the portion of the first cable exceeding the length of the second cable into a fifth section, and divide the second cable into four equal sections, so as to divide the navigation data into five target sections;

[0113] Based on seismic data processing software, the navigation data corresponding to the five target segments are plotted and processed to obtain data processing bins corresponding to the navigation bins;

[0114] Cross-comparing the navigation facet with the data processing facet to determine a cross-comparison result between the two facets;

[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 performing seismic data depth quality control on the seismic data based on the navigation bin and the data processing bin includes:

[0117] determining first navigation data in the navigation data that is related to the seismic data;

[0118] fusing and matching the collected seismic data with the first navigation data to obtain first seismic data;

[0119] Based on each interval segment corresponding to the five target segments, corresponding segment selection is performed on the first seismic data, and three-dimensional data processing is performed on each segment of the selected first seismic data to obtain seismic data volumes corresponding to the five target segments;

[0120] Creating data volume time slices for the seismic data volumes corresponding to the five target segments to obtain time slices corresponding to the five target segments;

[0121] The time slices corresponding to each target segment are compared with the navigation bins and data processing bins corresponding to each target segment to determine abnormal conditions of the seismic data.

[0122] As an optional but non-limiting implementation, the cross-comparing the navigation facet and the data processing facet includes:

[0123] The shape information, color code information and range information of each navigation facet are compared with the corresponding data processing facet.

[0124] As an optional but non-limiting implementation, after the seismic data is quality controlled, the data acquisition and processing system for the dual-vessel towing cables of unequal lengths further includes:

[0125] A migration profile determination module is used to perform Rayleigh integral migration on the collected seismic data to obtain a migration profile of the collection area;

[0126] A seismic record determination module, used for converting the migration profile into a seismic record based on a reverse migration technique;

[0127] The seismic record completion module is used to perform data interpolation 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.

[0128] The technical solution provided by the embodiment of the present invention is to collect data by towing cables of unequal lengths by the main ship, so that the longer cables can collect the long offset data required for full waveform inversion, and the other cables can collect the conventional data required for imaging. It can make full use of the lengths of different cables in the unequal length cables under limited equipment, and take into account both the conventional data required for imaging and the long offset data required for full waveform inversion. At the same time, by arranging an auxiliary ship capable of providing a seismic source on one side of the cable towed by the main ship, the conventional seismic data collected can be as close-channel data or near-mid-channel data as possible, thereby improving the resolution and imaging quality of the data.

[0129] The technical solution provided by the present invention and the data acquisition and processing system for two ships towing cables of unequal lengths provided in the embodiment can be used to execute the data acquisition and processing method for two ships towing cables of unequal lengths, and has the corresponding functional modules and beneficial effects for executing the data acquisition and processing method for two ships towing cables of unequal lengths.

[0130] The above description is only a preferred embodiment of the present invention and an explanation of the technical principles used. Those skilled in the art should understand that the disclosure scope involved in the present invention is not limited to the technical solution formed by a specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the above disclosed concept. For example, the above features are replaced with the technical features with similar functions disclosed in the present invention (but not limited to) by each other.

[0131] In addition, although each operation is described in a specific order, this should not be construed as requiring these operations to be performed in the specific order shown or in a sequential order. Under certain circumstances, multitasking and parallel processing may be advantageous. Similarly, although some specific implementation details are included in the above discussion, these should not be construed as limiting the scope of the present invention. Some features described in the context of a separate embodiment can also be implemented in a single embodiment in combination. On the contrary, the various features described in the context of a single embodiment can also be implemented in multiple embodiments individually or in any suitable sub-combination mode.

[0132] Although the subject matter has been described in language specific to structural features and / or methodological logical actions, it should be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or actions described above. On the contrary, the specific features and actions described above are merely example forms of implementing the claims.

Claims

1. A data collection and processing method for two ships towing cables of unequal lengths, characterized in that: The method comprises: The main ship tows a first number of first cables and a second number of second cables for travel, wherein the head ends of each of the first cables and each of the second cables 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 arranged on the same side of the main ship's turning direction, and the second cable array is arranged on the opposite side of the main ship's turning direction; the length of the first cable is greater than the length of the second cable; During the journey, the seismic source waves towed by the main ship and the auxiliary ship are alternately emitted to the seabed. The seismic reflection waves reflected by different underwater media are collected by the detectors configured on the towing cable of the main ship to obtain seismic data. The seismic data is subjected to quality control processing, and the quality control processing is used to determine whether the positioning and coverage of the collected seismic data meet preset conditions.

2. The method according to claim 1, characterized in that The auxiliary ship is arranged outside the second cable array and away from the first cable array; The distance between the first mapping position point on the reference line mapped by the position point of the auxiliary ship and the second mapping position point on the reference line mapped by the midpoint of the second cable is less than a preset difference; the reference line is a straight line in the extension direction of the cable; The vertical distance between the auxiliary ship and the central axis of the main ship is an integer multiple of half the width of the towing cable of the main ship, and the width of the towing cable is the total number of towing cables of the main ship multiplied by the cable spacing; the central axis of the main ship is the central axis of the main ship in the direction of cable extension.

3. The method according to claim 1, characterized in that There are at least two first cables, and the first number of the first cables does not exceed 40% of the total number of towing cables of the main ship.

4. The method according to claim 1, characterized in that: Each of the first cables is provided with a transverse bird, and the transverse bird is provided in a reference area of ​​the first cable, the reference area is an area formed between a reference demarcation point in the first cable and a tail end of the first cable, and the reference demarcation point is a point in the first cable aligned with the tail end of the second cable; At least one of the transverse birds is arranged in the reference area of ​​the first cable, and another one is arranged before the reference area; the distance between each two adjacent transverse birds meets the preset spacing.

5. The method according to claim 1, characterized in that The quality control processing of the seismic data comprises: The positioning navigation equipment configured on each positioning node on the towing cable of the main ship collects position data to obtain navigation data; Based on the five-segment method and seismic data processing software, real-time navigation bin positioning quality control is performed on the navigation data; the navigation bin is the bin corresponding to the navigation data; A data processing bin corresponding to the navigation bin obtained in the navigation bin positioning quality control process is acquired, and seismic data depth quality control is performed on the seismic data based on the navigation bin and the data processing bin.

6. The method according to claim 5, characterized in that The real-time navigation bin positioning quality control of the navigation data based on the five-segment method and seismic data processing software includes: Divide the portion of the first cable having the same length as the second cable into four equal sections, divide the portion of the first cable exceeding the length of the second cable into a fifth section, and divide the second cable into four equal sections, so as to divide the navigation data into five target sections; Based on seismic data processing software, the navigation data corresponding to the five target segments are plotted and processed to obtain data processing bins corresponding to the navigation bins; Cross-comparing the navigation facet with the data processing facet to determine a cross-comparison result between the two facets; If the cross comparison result is less than a preset threshold, the navigation data is normal.

7. The method according to claim 6, characterized in that The performing deep quality control of the seismic data on the seismic data based on the navigation bin and the data processing bin comprises: determining first navigation data in the navigation data that is related to the seismic data; fusing and matching the collected seismic data with the first navigation data to obtain first seismic data; Based on each interval segment corresponding to the five target segments, corresponding segment selection is performed on the first seismic data, and three-dimensional data processing is performed on each segment of the selected first seismic data to obtain seismic data volumes corresponding to the five target segments; Creating data volume time slices for the seismic data volumes corresponding to the five target segments to obtain time slices corresponding to the five target segments; The time slices corresponding to each target segment are compared with the navigation bins and data processing bins corresponding to each target segment to determine abnormal conditions of the seismic data.

8. The method according to claim 6, characterized in that The cross-comparison of the navigation facet and the data processing facet comprises: The shape information, color code information and range information of each navigation facet are compared with the corresponding data processing facet.

9. The method according to claim 1, characterized in that: After performing quality control processing on the seismic data, the method further includes: Performing Rayleigh integral migration on the collected seismic data to obtain a migration profile of the collection area; converting the migration profile into a seismic record based on a demigration technique; 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.

10. A data acquisition and processing system for two ships towing cables of unequal lengths, characterized in that: The system includes a main ship, an auxiliary ship, a cable towed by the main ship, and a data processing module, wherein: A main ship, used for towing the cable for traveling; the main ship also tows a seismic source; Auxiliary ship, with a towed seismic source, used to provide auxiliary seismic source; Seismic source waves alternately emitted underwater by seismic sources towed by the main ship and the auxiliary ship; The cables towed by the main ship include a first number of long cables and a second number of short cables; wherein the head ends of each of the first cables and each of the second cables 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 arranged on the same side of the main ship's turning direction, and the second cable array is arranged on the opposite side of the main ship's turning direction; the length of the first cable is greater than the length of the second cable; The cable is provided with a geophone, which is used to collect seismic reflection waves reflected by different underwater media to obtain seismic data; 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 preset conditions; the data processing module is arranged on the main ship.

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