CN106932815A - Ocean high-resolution system vertical array spark source - Google Patents

Abstract

The marine high-resolution three-dimensional vertical array electric spark source includes a water control excitation unit with a synchronous excitation control circuit, a depth sensor, and a cylindrical vertical array frame connected to the water control excitation unit through an energy transmission connection cable. A cylindrical electrode carrier with a negative electrode parallel to its axis, and the excitation unit is controlled on water to provide electric energy to the negative electrode for energy excitation. When in use, the electrical energy is output synchronously to the cathode electrodes of different depths, thereby generating source wavelets based on the different spatial depths of the cathode electrodes. The present application enables the wavelets generated between the cathode electrodes to suppress ghost reflections through the above design. Effectively systematically control the seismic wavelets generated by the excitation of a single cathode electrode, maximize the suppression of ghost reflections of the seismic wavelets generated by the excitation of the vertical array electric spark source, and greatly improve the resolution of field data acquisition for seismic exploration.

Description

Marine high-resolution three-dimensional vertical array EDM source

technical field

The invention relates to an electric spark seismic source in the process of marine seismic exploration, in particular to a marine high-resolution three-dimensional vertical array electric spark seismic source, which is used in a marine field high-resolution three-dimensional observation system to explore and collect seismic reflection information in the middle and shallow layers of the seabed and use it in Marine Geological Survey.

Background technique

In the marine field seismic exploration work, the seismic source is the key equipment in the marine seismic exploration data acquisition system, especially for the exploration of the middle and shallow layers of the ocean, the electric spark is one of the important seismic sources. In recent years, with the advancement of high-resolution seismic data acquisition technology and the improvement of environmental protection awareness of acquisition personnel, EDM sources have played a major role in marine seismic exploration. At present, the EDM seismic sources commonly used in China are mainly the SIG series produced by the French S.I.G company, and the Geo-spark series produced by the Dutch Geo-Resources company. The relevant marine electric spark sources developed at home and abroad are mainly combined excitation in the form of planar arrays, and the wavelet energy is increased linearly by combination to achieve the purpose of increasing the penetration depth of seismic waves in seismic exploration. However, with the improvement of seismic exploration technology requirements, how to widen the bandwidth of the source wavelet and increase its main frequency is a problem that geophysicists need to think about. How to suppress the virtual reflection brought by the water vapor interface, how to increase the energy and penetration depth, etc., are the focus of this patent based on the existing technology.

Contents of the invention

The purpose of the present invention is to provide a marine high-resolution three-dimensional vertical array EDM seismic source, to improve the effect of the EDM array to suppress ghost reflections through spatial differences, and to generate high-resolution seismic wavelets to be suitable for marine high-resolution multi-channel seismic Relevant technical requirements of the exploration system.

According to the relationship between the bubble wall pressure and time generated by the single electrode, that is, the bubble pulse of the single electrode, the present invention scientifically calculates the spatial relationship of each negative electrode in the vertical array, and combines them into a marine high-resolution three-dimensional vertical array based on the spatial difference between the electrodes. Electric spark source.

A marine high-resolution three-dimensional vertical array electric spark source is characterized in that it includes an above-water control excitation unit and an underwater depth sensor, and the above-water control and excitation unit is connected to the cylindrical vertical array through an energy transmission connection cable with an anode watertight joint. The top of the frame is connected, and the cylindrical vertical array frame is the entire seismic source electrode carrier, which includes a plurality of columnar electrode carriers, and each columnar electrode carrier is evenly arranged around the axis of the cylindrical vertical array frame, and each columnar electrode carrier They are all parallel to the axis and have the same distance from the axis, and the distance between every two adjacent columnar electrode carriers is equal; each columnar electrode carrier has a plurality of cathode electrodes arranged at equal intervals along the length direction; the direction of each cathode electrode is the same and They are all located in the radial direction of the columnar electrode carrier; the above-water control excitation unit includes a synchronous excitation control circuit, and provides electric energy to the negative electrode for energy excitation.

In actual work, the vertical array seismic source is placed vertically in seawater, and all electrodes are excited synchronously, so that the bubbles excited by each layer of cathode electrodes from top to bottom are superimposed in the same phase, and the distance between each layer of cathode electrodes at different depths is from sea level The depth of each layer is different, and the amplitude delay of the bubbles excited by each layer is superimposed, which can effectively suppress the ghost reflection of the sea surface.

The shape of the vertical array frame is a cylinder with a bottom diameter of 400mm and a height of 2000mm. It includes 16 columnar electrode carriers arranged vertically on the side of the cylinder. The distance between two adjacent columnar electrode carriers is 2cm. Each columnar electrode There are 100 cathode electrodes on the carrier, all cathode electrodes belong to the same circuit, and the distance between two adjacent cathode electrodes is 2cm; all cathode electrodes are arranged in a grid (each cathode electrode is connected to the upper, lower, left, and right adjacent cathode electrodes). electrodes are equally spaced).

The negative electrode is a copper wire wrapped with polyester material, and the energy range of a single electrode is 5-30J when it is discharged.

In order to ensure that the overall shaking of the vertical array EDM source is not very violent under the sea conditions with large swells, a balance weight ball is installed at the bottom of the cylindrical vertical array frame to eliminate the vibration of the source due to swells.

The overall excitation energy range of the seismic source designed above is 8000-48000J.

The anode watertight joint can be easily installed and disassembled, the balance weight ball 7 is used for balance adjustment of the vertical array frame in a free state in the water body, and the depth sensor is used for measuring the sinking depth of the seismic source.

The method for generating seismic source wavelets by using the above-mentioned marine high-resolution three-dimensional vertical array is characterized in that it comprises the following steps:

The vibrator is carried on the working boat and travels to the predetermined sea area, the device is hoisted into the water, and the depth pressure sensor 8 is used to detect whether it has reached the predetermined depth,

Synchronously output electric energy to cathode electrodes with different depths, so that source wavelets are generated based on different spatial depths of cathode electrodes, so that the generated source wavelets can suppress ghost reflections according to the spatial differences of cathode electrodes, thereby improving the energy of the source and earthquake The resolution of the wavelet is suitable for marine high-resolution seismic exploration.

The present invention has the following characteristics:

a. The marine high-resolution three-dimensional vertical array EDM seismic source utilizes the existing technology of cathode discharge consistency, and designs the spatial arrangement of the cathode electrodes in the form of the above-mentioned cylindrical vertical array, so that the wavelets generated between the cathode electrodes can suppress each other ghost reflection. Effectively systematically control the seismic wavelets generated by the excitation of a single cathode electrode, maximize the suppression of ghost reflections of the seismic wavelets generated by the excitation of the vertical array electric spark source, and greatly improve the resolution of field data acquisition for seismic exploration.

b. Cathode discharge is an existing technology. The characteristic of this technology is that electrode discharge does not consume materials and can maintain the wavelet consistency of a single electrode.

c. In order to ensure that the overall shake of the source is not very violent under the sea conditions with large swells, a balance weight ball is installed at the bottom of the source. The purpose is to use the free swing of the balance weight ball to limit the shaking angle of the vertical array source.

d. Using the depth pressure sensor 8, real-time transmission is used to determine the sinking depth of the cylinder, which is used to calculate the spatial distance for suppressing the ghost reflection.

e. The entire electrode arrangement is 16 symmetrical columnar electrode carriers, which are symmetrical to the centerline of the entire electrode frame and arranged at equal intervals on the side of the cylinder.

f. 100 electrodes arranged at equal intervals on each columnar carrier, all electrodes belong to the same circuit, and the electrode spacing is 2cm. With such an arrangement, the different spatial depths of the cathode electrodes 6 are utilized, so that the seismic wavelets generated by the cathode electrodes 6 at the same depth can be superimposed with each other with a time delay, effectively suppressing sea surface ghost reflections.

g. The cylindrical vertical array frame 4 has a base diameter of 400mm and a height of 2000mm. All electrodes belong to the same circuit and are excited simultaneously. The columnar electrode carriers 5 are separated by 2 cm, and a total of 16 columnar electrode carriers 5 surround the vertical array. The length of the negative electrode 6 on each columnar electrode carrier 5 is 2 cm, and the diameter of the bottom area is 5 mm. The structure of the cathode electrode 6 is a discharge copper wire 9 wrapped with a polyester material 10 .

Description of drawings

Fig. 1 is a schematic diagram of the marine high-resolution three-dimensional vertical array EDM source of the present invention.

Fig. 2 Schematic diagram of a single columnar electrode carrier.

Figure 3. Schematic diagram of a single cathode electrode.

Figure 4 is a perspective view of the overall frame of the seismic source, the columnar electrode carrier and the cathode electrode.

Fig. 5 is the seismic source wavelet produced when the total discharge capacity is 8000J by using the marine high-resolution three-dimensional vertical array EDM seismic source of the present invention.

FIG. 6 is the amplitude spectrum of the source wavelet shown in FIG. 5 .

Among them, 1. Water control excitation unit, 2. Energy transmission cable, 3. Anode watertight joint, 4. Cylindrical vertical array frame, 5. Columnar electrode carrier, 6. Cathode electrode, 7. Balance weight ball, 8. Depth Sensor, 9, discharge copper wire, polyester material 10.

detailed description

As shown in Figures 1-4, a marine high-resolution three-dimensional vertical array electric spark source is characterized in that it includes an above-water control excitation unit 1 and a depth sensor 8 located under water. The energy transmission cable 2 of the joint 3 is connected with the top of the cylindrical vertical array frame 4, the cylindrical vertical array frame 4 is the whole seismic source electrode carrier, and it includes a plurality of columnar electrode carriers 5, each of the columnar electrode carriers 5 Evenly arranged around the axis of the cylindrical vertical array frame 4, each columnar electrode carrier 5 is parallel to the axis and at the same distance from the axis, and the distance between every two adjacent columnar electrode carriers 5 is equal; each columnar electrode carrier 5 A plurality of cathode electrodes 6 are arranged at equal intervals along the length direction; each cathode electrode 6 has the same direction and is located in the radial direction of the columnar electrode carrier 5;

The above-water control excitation unit 1 includes a synchronous excitation control circuit, and provides electric energy to the negative electrode 6 for energy excitation.

In actual work, the vertical array seismic source is placed vertically in seawater, and all electrodes are excited synchronously, so that the bubbles excited by each layer of cathode electrodes 6 from top to bottom are superimposed in the same phase, and the distance between each layer of cathode electrodes 6 due to different depths The depth of the sea level is different, and the amplitude delay of the bubbles excited by each layer is superimposed, which can effectively suppress the ghost reflection of the sea surface.

The method for generating seismic source wavelets by using the above-mentioned marine high-resolution three-dimensional vertical array is characterized in that it comprises the following steps:

The vibrator is carried on the working boat and travels to the predetermined sea area, the device is hoisted into the water, and the depth pressure sensor 8 is used to detect whether it has reached the predetermined depth,

Synchronously output electric energy to the negative electrodes 6 of different depths, and utilize the different spatial depths of the negative electrodes 6 to generate seismic source wavelets, so that the generated seismic source wavelets can suppress ghost reflections according to the spatial differences of the negative electrodes 6, thereby improving the seismic source The energy and resolution of seismic wavelets are suitable for marine high-resolution seismic exploration.

Example

The shape of the cylindrical vertical array frame 4 is a cylinder with a bottom diameter of 400 mm and a height of 2000 mm. It includes 16 columnar electrode carriers 5 arranged vertically on the side of the cylinder, and the distance between two adjacent columnar electrode carriers 5 is 2 cm. Each columnar electrode carrier 5 is provided with 100 cathode electrodes 6, all cathode electrodes 6 belong to the same circuit, and the distance between two adjacent cathode electrodes 6 is 2cm; all cathode electrodes 6 are arranged in grid form.

The negative electrode 6 is a copper wire wrapped by polyester material, and the energy range of a single electrode is 5-30J when it is discharged.

In order to ensure that the overall shaking of the vertical array electric spark source is not very violent under the sea conditions with large waves, the underwater part of the source is equipped with a balance weight ball 7 at the bottom of the source, in order to eliminate the source swing caused by the surge .

The overall excitation energy range of the seismic source designed above is 8000-48000J.

The anode watertight joint 3 can be easily installed and disassembled, the balance weight ball 7 is used for balance adjustment of the vertical array frame in a free state in the water body, and the depth sensor 8 is used for measuring the sinking depth of the seismic source.

The energy transmission cable 2 is about 150m long, and a depth sensor 8 is installed on the top of the overall frame 4 of the seismic source. The balance weight ball 7 and the cathode electrode 6 are all integrated and installed on the overall frame 4 of the seismic source. Among them, every 100 cathode electrodes are integrated on a columnar electrode carrier, and then 20 columnar electrode carriers are sequentially installed on the cylindrical side of the overall frame of the seismic source.

The aforementioned 150m energy transmission cable 2 is integrated with multi-strand cables, which are connected through the anode watertight joint 3 . It includes 20 strands of cathode wire and anode wire for charging and discharging of power supply (corresponding to the number of columnar electrode carriers), 1 strand of real-time transmission line for depth sensor, and 1 strand of ground wire. Various cables are wrapped and integrated with insulating soft metal materials to prevent inductive effects between cables. All cable joints are integrated in the anode watertight joint 3, and the connection between the indoor unit and the outdoor unit is realized in the joint.

Based on the technology of cathode discharge, the present invention utilizes the position relationship of different spatial depths of synchronously excited cathode electrodes to calculate the time delay of the source wavelet (the time delay is determined by the depth at this time), and performs dislocation superimposition to suppress the ghost reflection phenomenon.

It can be seen from Fig. 5 and Fig. 6 that the source wavelet generated by the present invention has the characteristics of high bandwidth, high resolution and good suppression of ghost reflection, which meets the requirements of marine high-resolution seismic exploration.

Claims (6)

1. A marine high-resolution three-dimensional vertical array electric spark source, characterized in that it includes an above-water control excitation unit (1) and an underwater depth sensor (8), and the above-water control and excitation unit (1) is watertight with an anode The energy transmission connection cable (2) of the joint (3) is connected to the top of the cylindrical vertical array frame (4), which is the entire seismic source electrode carrier, which includes a plurality of columnar electrode carriers ( 5), each of the columnar electrode carriers (5) is uniformly arranged around the axis of the cylindrical vertical array frame (4), each columnar electrode carrier (5) is parallel to the axis and the distance from the axis is equal, and each adjacent two The spacing of the columnar electrode carriers (5) is equal; each columnar electrode carrier (5) is arranged with a plurality of cathode electrodes (6) at equal intervals along the length direction; each cathode electrode (6) has the same direction and is located in the columnar In the radial direction of the electrode carrier (5); the above-water control excitation unit 1 includes a synchronous excitation control circuit, and provides electric energy to the cathode electrode (6) for energy excitation. 2. The marine high-resolution three-dimensional vertical array EDM source as claimed in claim 1, characterized in that the shape of the cylindrical vertical array frame (4) is a cylinder with a bottom diameter of 400mm and a height of 2000mm, which includes 16 columnar electrode carriers (5) arranged vertically on the side of the cylinder, the distance between two adjacent columnar electrode carriers (5) is 2cm, and each columnar electrode carrier (5) is provided with 100 cathode electrodes (6), All the cathode electrodes (6) belong to the same circuit, and the distance between two adjacent cathode electrodes (6) is 2cm; all the cathode electrodes (6) are arranged in grid form. 3. The marine high-resolution three-dimensional vertical array EDM source as claimed in claim 1 or 2, characterized in that the cathode electrode (6) is a copper wire wrapped in polyester material, and the energy range of a single electrode discharge is 5 -30J. 4. The marine high-resolution three-dimensional vertical array EDM source according to claim 1 or 2, characterized in that a balance weight ball (7) is installed at the bottom of the cylindrical vertical array frame (4) to eliminate the The resulting vibration of the source. 5. The marine high-resolution three-dimensional vertical array EDM seismic source as claimed in claim 3, characterized in that the overall excitation energy range of the designed seismic source is 8000-48000J. 6. Utilize above-mentioned marine high-resolution three-dimensional vertical array EDM source to produce the method for seismic source wavelet, it is characterized in that comprising the following steps: The vibrator is carried on the working boat and driven to the predetermined sea area, hoisted the device into the water, and the depth pressure sensor (8) is used to detect whether it has reached the predetermined depth, Synchronously output electric energy to the cathode electrodes (6) at different depths, thereby generating source wavelets based on the different spatial depths of the cathode electrodes (6), so that the generated source wavelets can suppress virtual waves according to the spatial differences of the cathode electrodes (6). reflection, thereby improving the energy of the source and the resolution of the seismic wavelet, which is suitable for marine high-resolution seismic exploration.