A marine streamer seismic acquisition apparatus and method

Abstract

The application discloses a marine towed cable seismic acquisition device and method. The device comprises a first seismic source device, a second seismic source device, a third seismic source device and a cable array; the cable array is formed by parallel arrangement of a preset number of cables in a straight line state, and the cable array is in the shape of a parallelogram; the first seismic source device is arranged at a first position on a first side of the cable array, the second seismic source device and the third seismic source device are arranged at a second position on a second side and a third position on a third side of the cable array, and the first seismic source device is configured to control the first seismic source device, the second seismic source device and the third seismic source device to be sequentially excited in a preset order, so that the cables in the cable array collect near trace information after the seismic source excitation. The first seismic source device, the second seismic source device and the third seismic source device are arranged at corresponding positions and sequentially excited in a preset order, so that the problem of insufficient near trace information is solved.

Description

Technical Field

[0001] This invention relates to the field of marine seismic exploration technology, and in particular to a marine towed cable seismic acquisition device and method. Background Technology

[0002] As exploration progresses, the requirements for seismic data become increasingly stringent, especially for near-path seismic data. The quality of marine seismic data acquisition is affected by many factors, among which the method of acquiring marine seismic data is particularly important.

[0003] Currently, in towed seismic acquisition, the seismic source is generally positioned at the front end of the cable, i.e., the source is in front and the cable is behind. This results in a one-sided seismic reflection record, which leads to insufficient coverage of the short-path, resulting in inadequate short-path information and thus hindering the development of seismic exploration technology. Therefore, obtaining rich short-path information is crucial. Summary of the Invention

[0004] This invention provides a marine towed seismic acquisition device and method to solve the problem of insufficient short-distance information.

[0005] According to one aspect of the present invention, a marine towed seismic acquisition device is provided, the device comprising: a first source device, a second source device, a third source device, and a cable array; The cable array is a planar array formed by a predetermined number of cables arranged in parallel in a straight line, and the cable array is in the shape of a parallelogram. The first seismic source device is configured at a first position on a first side of the cable array, the first side of the cable array corresponding to the cable ports of a predetermined number of cables in the cable array; The second seismic source device and the third seismic source device are configured at the second position on the second side and the third position on the third side of the cable array, respectively, with the second side and the third side of the cable array corresponding to one cable side on each side of the cable array. The first seismic source device is configured to control the first seismic source device, the second seismic source device, and the third seismic source device to be excited sequentially in a preset order, so that the cables in the cable array can collect the shortcut information after the seismic source is excited. The preset order is to first excite the first side source of the seismic source device and then excite the second side source of the seismic source device.

[0006] According to another aspect of the present invention, a method for seismic acquisition using a towed cable at sea is provided, the method comprising: Acquire the source timing excitation signal; wherein the source timing excitation signal is used to describe the order of source excitation; Based on the aforementioned seismic source timing excitation signal, the seismic source is controlled to excite, so that the cable can collect the shortcut information after the seismic source excitation.

[0007] The technical solution of this invention includes a first seismic source device, a second seismic source device, a third seismic source device, and a cable array. The cable array is a planar array formed by a predetermined number of cables arranged in parallel in a straight line, and the cable array is in the shape of a parallelogram. The first seismic source device is configured at a first position on a first side of the cable array, and the second and third seismic source devices are configured at a second position on a second side and a third position on a third side of the cable array. The first seismic source device is configured to control the first, second, and third seismic source devices to be excited sequentially in a predetermined order, so that the cables in the cable array can collect the short-path information after the seismic source is excited. This application solves the problem of insufficient short-path information by placing the first, second, and third seismic source devices in corresponding positions and exciting them sequentially in a predetermined order.

[0008] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0009] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0010] Figure 1 This is a schematic diagram of the structure of a marine towed seismic acquisition device according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of a marine towed seismic acquisition device applicable to an embodiment of the present invention; Figure 3 This is a schematic diagram of the structure of a marine towed seismic acquisition device applicable to an embodiment of the present invention; Figure 4 This is a flowchart of a marine towed cable seismic acquisition method provided by an embodiment of the present invention. Detailed Implementation

[0011] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0012] It should be noted that the terms "first," "second," and "third," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0013] Figure 1 This is a schematic diagram of a marine towed cable seismic acquisition device provided in an embodiment of the present invention. This embodiment is applicable to the acquisition of short-range information, such as... Figure 1 As shown, the device includes: a first seismic source device 110, a second seismic source device 120, a third seismic source device 130, and a cable array 140; The cable array 140 is a planar array formed by a preset number of cables arranged in parallel in a straight line, and the cable array is in the shape of a parallelogram. The first source device 110 is configured at a first position on a first side of the cable array, the first side of the cable array corresponding to the cable ports of a predetermined number of cables in the cable array; The second source device 120 and the third source device 130 are configured at the second position on the second side and the third position on the third side of the cable array, respectively, with the second side and the third side of the cable array corresponding to one cable side on each side of the cable array. The first seismic source device is configured to control the first seismic source device 110, the second seismic source device 120 and the third seismic source device 130 to be excited sequentially in a preset order, so that the cables in the cable array can collect the shortcut information after the seismic source is excited. The preset order is to first excite the first side source 21 of the seismic source device and then excite the second side source 22 of the seismic source device.

[0014] For example, such as Figure 1 As shown, the first, second, and third seismic source devices can be seismic source vessels carrying seismic sources. The first seismic source device is the main seismic source vessel, while the second and third seismic source devices are auxiliary seismic source vessels, distributed on both sides of the cable array. During seismic source activation, the first side seismic source 21 of the seismic source devices must be activated sequentially first, followed by the second side seismic source 22 of the seismic source devices.

[0015] Optional, see Figure 1 The second and third positions are symmetrically distributed relative to the first reference plane, and the projected distances from both positions are within a first preset distance range. The first reference plane passes through the center of the cable array and is perpendicular to the plane containing the cable array. The first reference plane is parallel to the reference travel direction, which is the direction in which the first source device moves on the second reference plane. The line connecting the second and third positions passes through the central region of the cable array; the central region is a circular area with a preset radius centered on the array center. This arrangement ensures that the source excitation is within the short-range, resulting in more accurate short-range information.

[0016] When the cable array is arranged in a rectangular shape, it is arranged in parallel according to a preset spacing. The first preset distance is determined based on the preset quantity and preset spacing; for details, please refer to [the relevant documentation / reference]. Figure 2 The second preset distance is equal to the product of the preset quantity N and the preset spacing M. For example, the preset spacing can be set to 50m to reduce the area size and improve the acquisition accuracy; in addition, when high-efficiency operation is required, the preset spacing can be set to 100m to improve the operation efficiency.

[0017] Optionally, the second seismic source device 120 is configured at a second position on the second side of the cable array 140, and the third seismic source device 130 is configured at a third position on the third side of the cable array 140. For example, the second position on the second side of the cable array is as follows: Figure 1 As shown, on the left side of the cable array along the navigation direction, the third position on the third side of the cable array is as follows. Figure 1 The cable array shown is located on the right side along the direction of navigation and is symmetrically distributed.

[0018] Optionally, the first seismic source device is configured to control the first seismic source device, the second seismic source device, and the third seismic source device to be excited sequentially in a preset order, and the process further includes the following: The first seismic source device is configured to control seismic source excitation according to a preset time interval and a preset seismic source excitation sequence. The preset time interval is the time between two consecutive seismic source excitations, and is a value within a preset time range. That is, the times of two consecutive seismic source excitations can be the same or different, as long as they are within the preset time range. In this application, the preset time interval takes different values. The preset seismic source excitation sequence is the first seismic source device, the second seismic source device, and the third seismic source device. For example, as shown... Figure 2 A schematic diagram of a marine towed seismic acquisition device applicable to an embodiment of the present invention is shown below. Figure 2 The first and second side sources of the first source device are named S1 and S2, the first and second side sources of the second source device are named S3 and S4, and the first and second side sources of the third source device are named S5 and S6. A preset time interval is set according to actual needs, such as 3-4 seconds. The preset time interval is a value between 3 and 4 seconds. Then, the source is excited in the order of S1, S3, S5, S2, S4 and S6 to make the obtained shortcut information richer.

[0019] Optionally, the cable array is positioned within the immersion depth range in the water. If the immersion depth of the cable array exceeds a preset depth, the second and third seismic source devices are placed at a second preset distance. The second preset distance is determined based on preset spacing and preset quantity. The immersion depth is the distance from the sea level to the cable array, and the preset depth is the maximum immersion depth within the immersion range. The preset depth is selected based on the actual target layer depth during the detection process. For example, setting the preset depth to 15 meters reduces the distance between the second and third seismic source devices and the cable array. Alternatively, the second preset distance can be set to half the product of the preset spacing M and the preset quantity N.

[0020] When the cable array is submerged to a depth greater than a preset depth, this scheme involves placing the second and third seismic source devices at a second preset distance. This approach allows for the acquisition of richer low-frequency information, which, combined with ghost wave removal techniques, broadens the frequency band. Furthermore, it provides data with a higher signal-to-noise ratio, laying a solid foundation for frequency extension processing. Simultaneously, deeper cable submersion increases the safety of this operational method.

[0021] In one feasible embodiment, optionally, such as Figure 3 This is a schematic diagram of the structure of a marine towed seismic acquisition device applicable to an embodiment of the present invention. See also... Figure 3 When the cable array shifts from a rectangular shape to a parallelogram shape, the second and third positions are updated, and the second and third seismic source devices are moved to the updated second and third positions. The specific process is as follows: The first offset distance ab and the second offset distance bc are determined based on the array center before and after the update. The first offset distance is the distance from the array center a before the update to the target point b, and the second offset distance is the distance from the target point b to the array center c after the update. The target point is the intersection of a straight line passing through the array center before the update and parallel to the direction of travel, and a straight line passing through the array center after the update and perpendicular to the direction of travel. Then, the second and third positions are updated based on the first and second offset distances. Furthermore, the second and third seismic source devices are controlled to first move along the first direction by the first offset distance, and then move along the second direction by the second offset distance. The first direction is the direction of travel, and the second direction is perpendicular to the direction of travel and points towards the offset of the cable array. For example, as shown... Figure 3 In the diagram, the first direction is the direction from the array center a before the update to the target point b, and the second direction is the direction from the target point b to the array center c after the update.

[0022] Optional, such as Figure 3 As shown, θ is the feather angle, which is the angle between the cable array and the ship's direction of travel caused by the tide. The auxiliary vessel is always located in the middle of the cable. When the cable array exhibits a feather angle, the first offset distance ab can be calculated according to the following formula: Where L is the cable length.

[0023] This solution ensures that the coverage of the near-pass and near-center passes reaches more than 80% of the total designed coverage when the cable array shifts, by adjusting the positions of the second and third seismic source devices in real time. Compared with the traditional solution that uses the main ship's surface elements for rudder repair, where the coverage of some weakly covered surface elements in the near-pass and near-center passes is only 30%, this solution greatly improves the richness of the near-pass information obtained.

[0024] The technical solution of this invention includes a first seismic source device, a second seismic source device, a third seismic source device, and a cable array. The cable array is a planar array formed by a predetermined number of cables arranged in parallel in a straight line, and the cable array is in the shape of a parallelogram. The first seismic source device is configured at a first position on a first side of the cable array, and the second and third seismic source devices are configured at a second position on a second side and a third position on a third side of the cable array. The first seismic source device is configured to control the first, second, and third seismic source devices to be excited sequentially in a predetermined order, so that the cables in the cable array can collect the short-path information after the seismic source is excited. This application solves the problem of insufficient short-path information by placing the first, second, and third seismic source devices in corresponding positions and exciting them sequentially in a predetermined order.

[0025] Figure 1This is a flowchart illustrating a marine towed cable seismic acquisition method according to an embodiment of the present invention. This embodiment is applicable to the acquisition of short-haul information. Figure 1 As shown, the method includes: S110. Obtain the source timing excitation signal; wherein the source timing excitation signal is used to describe the order of source excitation.

[0026] This embodiment follows Figure 1 As shown, the first seismic source device, the second seismic source device, the third seismic source device, and the cable array are placed at sea to generate seismic sources and obtain short-range information.

[0027] Specifically, to obtain more accurate shortcut information, the activation sequence of the seismic sources, i.e., the seismic source timing signal, needs to be determined before the seismic source is activated, so that the first seismic source device can activate the seismic source according to the seismic source timing signal. The range of the shortcut can be determined according to the cable length. In this scheme, each cable is of the same length.

[0028] S120. Based on the seismic source timing excitation signal, control the seismic source to excite so that the cable can collect the short-distance information after the seismic source is excited.

[0029] Specifically, the seismic source timing excitation signal first excites the seismic source on the first side of each seismic source device sequentially, and then excites the seismic source on the second side of the seismic source device once. For example, the first side seismic source of the first seismic source device, the first side seismic source of the second seismic source device, the first side seismic source of the third seismic source device, the second side seismic source of the first seismic source device, the second side seismic source of the second seismic source device, and the second side seismic source of the third seismic source device are excited according to a preset time interval. The first seismic source device is the main seismic source vessel, and the second and third seismic source devices are auxiliary seismic source vessels. The preset time interval is the time between two consecutive seismic source excitations. The preset time interval is a value within a preset time range; that is, the time of two consecutive seismic source excitations can be the same or different, as long as it is within the preset time range. This application uses different values ​​for the preset time interval, such as... Figure 2 The seismic source is set with a preset time interval according to actual needs, such as 3-4 seconds. The preset time interval is a value between 3 and 4 seconds. Then, S1, S3, S5, S2, S4, and S6 are excited according to the preset time interval to obtain richer shortcut information. Alternatively, the seismic source can be excited sequentially according to a preset distance traveled by the first seismic source device. For example, the first seismic source device can be excited by S1, S3, S5, S2, S4, and S6 according to a preset distance; that is, the first seismic source device travels a preset distance, excites S1, then travels another preset distance, excites S3, and so on in sequence.

[0030] When collecting short-path information, if short-path information is missing, auxiliary source ship surface element correction is used to solve the problem of uneven surface element coverage caused by feather angle differences. In the end, high signal-to-noise ratio towed cable seismic data can be obtained, which meets the requirements of fine imaging in complex tectonic areas.

[0031] The marine towed cable seismic acquisition method provided in this embodiment of the invention can be applied to any marine towed cable seismic acquisition device provided in this embodiment of the invention, and has the corresponding functional modules and beneficial effects for executing the method.

[0032] The acquisition, storage, use, and processing of data in this application comply with relevant national laws and regulations and do not violate public order and good morals.

[0033] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0034] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A marine towed cable seismic acquisition device, characterized in that, include: The first seismic source device, the second seismic source device, the third seismic source device, and the cable array; The cable array is a planar array formed by a predetermined number of cables arranged in parallel in a straight line, and the cable array is in the shape of a parallelogram. The first seismic source device is configured at a first position on a first side of the cable array, the first side of the cable array corresponding to the cable ports of a predetermined number of cables in the cable array; The second seismic source device and the third seismic source device are configured at the second position on the second side and the third position on the third side of the cable array, respectively, with the second side and the third side of the cable array corresponding to one cable side on each side of the cable array. The first seismic source device is configured to control the first seismic source device, the second seismic source device, and the third seismic source device to be excited sequentially in a preset order, so that the cables in the cable array can collect the short-path information after the seismic source is excited. The preset order is to first excite the first side source of the seismic source device and then excite the second side source of the seismic source device. The second and third positions are symmetrically distributed relative to the first reference plane, and the projection distances of the second and third positions to the first reference plane are both within a first preset distance range. The first reference plane passes through the center of the cable array and is perpendicular to the plane containing the cable array. The first reference plane is parallel to the reference travel direction, which is the direction of movement of the first seismic source device on the second reference plane. The second reference plane is parallel to the plane containing the cable array. The line connecting the second and third positions passes through the central region of the cable array. The central region is a circular area with a preset radius centered on the array center. When the cable array is arranged in a rectangular shape, it is arranged in parallel at a preset spacing. The first preset distance is determined based on a preset number and a preset spacing. The second seismic source device is configured at a second position on a second side of the cable array, and the third seismic source device is configured at a third position on a third side of the cable array. The first seismic source device is configured to control the first seismic source device, the second seismic source device, and the third seismic source device to be excited sequentially in a preset order, including: The first seismic source device is configured to control the excitation of the seismic source according to a preset time interval and a preset seismic source excitation sequence; wherein, the preset time interval is the time between two consecutive seismic source excitations, and the preset time interval is a value in a preset time range; the preset seismic source excitation sequence is the first side source of the first seismic source device, the first side source of the second seismic source device, the first side source of the third seismic source device, the second side source of the first seismic source device, the second side source of the second seismic source device, and the second side source of the third seismic source device.

2. The apparatus according to claim 1, characterized in that, The cable array is within the immersion depth range in the water. When the immersion depth of the cable array is greater than the preset depth, the second and third seismic source devices are placed at a second preset distance. The second preset distance is determined according to the preset spacing and preset quantity. The immersion depth is the distance between the sea level and the cable array. The preset depth is the maximum immersion depth in the immersion range.

3. The apparatus according to claim 1, characterized in that, When the cable array shifts from a rectangular shape to a parallelogram shape, the second and third positions are updated, and the second and third source devices are controlled to move to the updated second and third positions.

4. The apparatus according to claim 3, characterized in that, When the cable array shifts from a rectangular shape to a parallelogram shape, the second and third positions are updated, including: The first offset distance and the second offset distance are determined based on the array center before the update and the array center after the update; wherein, the first offset distance is the distance from the array center before the update to the target point, and the second offset distance is the distance from the target point to the array center after the update, and the target point is the intersection of a straight line passing through the array center before the update and parallel to the direction of travel and a straight line passing through the array center after the update and perpendicular to the direction of travel. The second and third positions are updated based on the first and second offsets.

5. The apparatus according to claim 4, characterized in that, Controlling the second and third seismic source devices to move to the updated second and third positions includes: The second and third seismic source devices are controlled to move the first offset distance along the first direction and then move the second offset distance along the second direction; wherein the first direction is the direction of travel and the second direction is the direction perpendicular to the direction of travel and pointing towards the offset of the cable array.

6. A method for seismic acquisition using a towed cable at sea, characterized in that, The marine towed seismic acquisition device according to any one of claims 1-5 includes: Acquire the source timing excitation signal; wherein the source timing excitation signal is used to describe the order of source excitation; Based on the aforementioned seismic source timing excitation signal, the seismic source is controlled to excite, so that the cable can collect the short-path information after the seismic source excitation; The source timing excitation signal is used to excite the first side source of the first source device, the first side source of the second source device, the first side source of the third source device, the second side source of the first source device, the second side source of the second source device, and the second side source of the third source device according to a preset time interval; the preset time interval is the time between two consecutive source excitations, and the preset time interval is a value in a preset time range.

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