Shaft bottom detector coupling device

Abstract

The invention relates to a shaft bottom detector coupling device, and belongs to the field of oil and gas seismic exploration. The shaft bottom geophone coupling device comprises a geophone and a geophone cabin body, the geophone is fixedly installed in the geophone cabin body, and the geophone cabin body is provided with a channel used for leading out a geophone signal line; the detector cabin body forms a counterweight body, or a counterweight block is installed below the detector cabin body and forms the counterweight body together with the detector cabin body. According to the invention, the self weight of the counterweight body can be used to control the attitude of the well bottom detector in the descending process, so that the well bottom detector can be vertically inserted into the stratum and the coupling between the detector and the well bottom stratum is increased; the problem that in the prior art, the posture of a well bottom detector is difficult to control in the well descending process, and consequently the quality of received signals is poor is effectively solved.

Description

Technical Field

[0001] The invention relates to a bottom hole geophone coupling device and belongs to the field of oil and gas seismic exploration. Background Art

[0002] Due to its unique seismic geological conditions, the loess plateau has a dramatic surface topography with gullies and ravines, and the loess layer is extremely thick, which seriously attenuates the absorption of seismic reflection waves. Therefore, it is of great significance to clarify the precise Q value of each velocity layer of the thick loess layer for the later data processing of the loess plateau. Due to the limitations of cost and detector technology, there has been a lack of deep well (generally more than 150 meters) downhole detectors for receiving data in the surface survey of seismic exploration.

[0003] In current land seismic exploration operations, micro-well logging surveys mainly use single-well or double-well micro-well logging operations to directly measure the seismic wave velocity from the surface to the bottom of the shallow well. Due to problems such as construction technology, survey methods, cost-effectiveness and cost, the existing technology results in inaccurate or incomplete Q values.

[0004] The Chinese patent application document with application publication number CN113267805A discloses a bottom hole detector coupling device, such as Figure 4 As shown, the bottom hole detector coupling device includes a bottom hole detector and a sleeve-supported downhole casing, wherein the bottom hole detector includes a detector core 13, a detector core shell 15, a detector signal line 14 and a cylindrical pin body; the cylindrical pin body includes a sleeve-supported base 12 and a sleeve-supported pile 11, the detector core 13 is located in the detector core shell 15, the tail of the detector core shell 15 is made into a cone (i.e., tail cone 16), and the detector core shell is made of aluminum alloy. The sleeve-supported downhole casing includes a lower explosive blasting rod 17, a casing cap 18 and a sleeve-supported detector casing 19, the lower explosive blasting rod 17, the casing cap 18 and the sleeve-supported detector casing 19 are connected in sequence, and the side wall of the sleeve-supported detector casing 19 includes a casing slit 20. The bottom hole geophone is vertically inserted into the bottom hole formation by the downward pressure of the casing. Due to its structure, shape and downhole operation method, the received signal is unstable.

[0005] The existing technology currently has the following problems:

[0006] 1. After being immersed in high-pressure mud at the bottom of an ultra-deep well for a long time, water leakage may occur, causing the detector core to malfunction in the water and affecting the quality of the received signal.

[0007] 2. When going down the well, it is difficult to control the posture of the bottom hole detector and ensure that it is upright at the bottom of the well. Although the direction of the detector can be controlled by inserting steel bars, explosive rods, etc. or by using sleeve support, for deep wells (depth > 150 meters), the tail cone under the detector is easily inserted into the well wall due to the length and weight restrictions of the explosive rod in ultra-deep well construction, resulting in the inability to quickly and efficiently send it directly to the bottom of the well.

[0008] 3. It is impossible to ensure that the bottom hole detector is in the best coupling state with the formation. The working state of the bottom hole detector requires that it is perpendicular to the bottom hole formation to work normally and obtain high-quality seismic records. In the existing technology, the detector cannot be guaranteed to be in a vertical state at the bottom of the ultra-deep well. Although some tools can be used to increase the downward pressure to improve the coupling effect, the posture of the detector cannot be adjusted to make it fully coupled with the formation, resulting in weak received energy. Summary of the invention

[0009] The object of the present invention is to provide a bottom hole detector coupling device, which is used to solve the problem in the prior art that the bottom hole detector is difficult to control in the process of going down the well, resulting in poor quality of received signals.

[0010] To achieve the above purpose, the technical solution provided by the present invention is:

[0011] The present invention provides a bottom hole detector coupling device, comprising a detector and a detector cabin, wherein the detector is fixedly installed in the detector cabin, and a channel for leading out a detector signal line is provided on the detector cabin; the detector cabin itself forms a counterweight body, or a counterweight block is installed under the detector cabin to form a counterweight body together with the detector cabin.

[0012] The bottom hole detector coupling device proposed in the present invention includes a detector and a detector cabin. The detector is fixedly installed in the detector cabin. Since the detector cabin itself has weight, or a counterweight block is installed under the detector cabin to form a counterweight body together with the detector cabin. Compared with the prior art, the present invention can use the weight of its counterweight body to control the posture of the bottom hole detector during the process of going down the well, and can ensure that the bottom hole detector is vertically inserted into the formation, increase the coupling between the detector and the bottom hole formation, and effectively avoid the problem of poor quality of the received signal caused by the difficulty in controlling the posture of the bottom hole detector during the process of going down the well in the prior art.

[0013] Furthermore, the detector cabin is a cylinder.

[0014] The detector cabin of the present invention is a cylinder, which makes it convenient for personnel to place the detector cabin into the well.

[0015] Furthermore, a top cover is arranged above the detector cabin, and a hole is opened on the top cover for leading out the detector signal line.

[0016] A top cover is arranged above the cabin of the geophone of the present invention, and a hole is provided on the top cover to facilitate personnel to lead the wires.

[0017] Furthermore, the detector includes two detector cores, and the detector cores are fixed in the detector cabin through rubber pads.

[0018] The detector of the present invention comprises two detector cores, which are fixed in the detector cabin through rubber pads. The structure is simpler than that of the existing detector device and the operation is easier.

[0019] Furthermore, an insulating pad is installed between the two detector cores.

[0020] Insulation pads are used between the two detector cores of the present invention to insulate the two detector cores from interference.

[0021] Furthermore, the gap between the detector cabin and the detector is filled with waterproof material.

[0022] The present invention uses waterproof material for sealing, and the sealing operation is simple, thus solving the problem of water leakage of the detector cabin when it is immersed in a deep well.

[0023] Furthermore, a sealing ring is installed between the top cover and the detector cabin.

[0024] A sealing ring is installed between the top cover and the detector cabin of the present invention, which also enhances the sealing and waterproof performance of the entire detector coupling device.

[0025] Furthermore, the top cover is fixed to the detector cabin by screw connection.

[0026] The present invention fixes the top cover on the detector cabin body by means of screws, and is easy to install.

[0027] Furthermore, a lifting ring is installed on the top cover, and the lifting ring is used to connect with the cable.

[0028] The present invention vertically inserts the bottom hole geophone coupling device into the bottom hole formation through the cable, which has stronger firmness and is convenient for connecting the cable for the retraction and extension of the geophone.

[0029] Furthermore, the detector cabin is made of pure steel.

[0030] The geophone cabin of the present invention is made of pure steel, which is firm and durable, and can increase the weight of the geophone itself to facilitate the smooth lowering of the geophone to the bottom of the well. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of the ultra-deep micro-well logging observation system of the present invention;

[0032] Figure 2It is a schematic diagram of the layout of the ground geophone of the present invention;

[0033] Figure 3 It is a schematic diagram of the structure of the bottom hole geophone coupling device of the present invention;

[0034] Figure 4 It is a schematic diagram of the structure of a bottom hole geophone in the prior art of the present invention;

[0035] Figure 5 It is a data diagram received by the bottom hole geophone in the prior art of the present invention;

[0036] Figure 6 This is a diagram of data received by a bottom hole geophone according to an embodiment of the present invention;

[0037] Figure 7 This is a diagram of data received by a bottom hole geophone according to an embodiment of the present invention;

[0038] Figure 8 It is an embodiment of the present invention receiving data bottom well gather record, different depth window analysis display diagram;

[0039] In the figure: 1. Geophone cabin; 2. Rubber pad; 3. Round hole; 4. Screw; 5. Sealing ring; 6. Top cover; 7. Geophone core; 8. Insulation pad; 9. Lifting ring;

[0040] 11. Support pile; 12. Support base; 13. Detector core; 14. Detector signal line; 15. Detector core shell; 16. Tail vertebrae; 17. Explosive rod; 18. Casing cap; 19. Support detector casing; 20. Casing slit. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0042] Embodiment of the bottom hole detector coupling device:

[0043] The bottom hole detector coupling device of the present invention comprises a detector and a detector cabin, wherein the detector is fixedly installed in the detector cabin, and the detector cabin itself has weight, or a counterweight is installed under the detector cabin to form a counterweight body together with the detector cabin. Compared with the prior art, the present invention can use the weight of the counterweight body to control the posture of the bottom hole detector during the process of going down the well, and can ensure that the bottom hole detector is vertically inserted into the formation, increase the coupling between the detector and the bottom hole formation, and effectively avoid the problem in the prior art that the posture of the bottom hole detector is difficult to control during the process of going down the well, resulting in poor quality of the received signal.

[0044] The specific structure of the bottom hole detector coupling device of this embodiment is as follows: Figure 3As shown, the detector cabin 1 is a cylinder made of pure steel, that is, a cavity for installing the detector is set in the cylinder to form the detector cabin; wherein the detector includes two detector cores, and the detector core 7 is fixed in the detector cabin 1 by a rubber pad 2, and an insulating pad 8 is installed between the two detector cores. In order to withstand the pressure of the mud at the bottom of the deep well, the outer shell of the detector core is also made of steel. In order to facilitate the installation of the detector in the detector cabin, the cavity in this embodiment runs through the upper surface of the cylinder. Therefore, a top cover 6 needs to be set above the detector cabin 1 for sealing. A circular hole 3 is provided on the top cover 6 for leading out the detector signal line. The top cover 6 is fixedly mounted on the detector cabin 1. In order to improve the sealing performance, a sealing ring 5 is installed between the top cover 6 and the detector cabin 1. Butter is used to seal the gap between the detector cabin 1 and the top cover 6. The gap between the detector cabin 1 and the detector is filled with waterproof material to prevent the detector cabin from leaking when immersed in a deep well.

[0045] Since the detector cabin in this embodiment is made of pure steel, has a diameter of 8 cm and a weight of 25 kg, the detector cabin itself can be used as a counterweight. This embodiment can use the weight of its counterweight to better control the posture of the bottom-hole detector during the process of lowering the well. As other implementations, the detector cabin can also be made of other lightweight materials, such as aluminum. When aluminum is used, in order to better control the posture of the bottom-hole detector during the process of lowering the well, it is necessary to set a counterweight on the detector cabin. For example, a steel counterweight is fixedly installed under the detector cabin. This can better ensure the control of the posture of the bottom-hole detector during the process of lowering the well, and it is convenient for personnel to replace it later.

[0046] The top cover in this embodiment can be fixedly mounted on the detector cabin by screws 4. As other embodiments, the top cover can also be fixed on the detector cabin by nuts and bolts, or by riveting. In this embodiment, a component is installed on the top cover to facilitate the connection of the stressed steel wire rope in the cable. The component used in this embodiment is a lifting ring 9.

[0047] Before using the bottom hole geophone coupling device of the present invention, first, select a driller with rich experience in drilling construction and special drilling equipment for construction, equip with water tankers, mud powder and other cementing materials, fully wash the well, ensure the quality of well completion, and reach the designed well depth. Use special equipment to drill a 100 mm wellhead diameter, each to reach a certain designed depth, usually greater than 100 meters, the excitation well and the receiving well, the excitation well and the receiving well have the same depth, and the distance between the excitation well and the receiving well is 5 meters. Then, according to the schematic diagram of the ultra-deep micro-well logging observation system, arrange the bottom hole geophone coupling device and the ground geophone. The schematic diagram of the ultra-deep micro-well logging observation system is shown in FIG. Figure 1As shown. In this embodiment, a special excitation cable is manufactured according to the designed depth. The excitation spacing near the wellhead is 1 meter, and the excitation spacing from the wellhead downward is 2 meters, 4 meters, and 2 meters near the bottom of the well. The bottom-hole detector coupling device of the present invention is connected to the stressed steel wire rope in the cable, and the excitation cable is lowered into the excitation well to ensure the accuracy of the depth and position of the excitation point. Finally, the ground detector is deployed, such as Figure 2 shown.

[0048] In order to illustrate the effect of the present invention, the measurement results of the bottom hole geophone coupling device of the present invention are compared with the measurement results of the existing bottom hole geophone.

[0049] The schematic diagram of the bottom hole detector structure in the prior art is as follows: Figure 4 As shown in FIG. 1 , the existing bottom-hole geophones have an incorrect posture during the downhole process due to their shape, structure and downhole operation mode, and the coupling quality with the bottom-hole formation is not high. The reflection on the bottom-hole geophone receiving signal is that the first arrival is not strong enough and the virtual reflection interface signal is weak, such as Figure 5 shown.

[0050] The bottom hole detector coupling device in this embodiment can be vertically inserted into the bottom hole, and has good coupling with the formation. The data collected finally is shown as follows: Figure 6 and Figure 7 As shown, the energy of the first arrival wave is relatively strong, and the near-surface ghost reflection interface signal is relatively clear, which can meet the quality requirements of bottom hole seismic records for near-surface formation parameter investigation.

[0051] The bottom hole geophone coupling device of the present invention is used to obtain the bottom hole track gather records. The window analysis at different depths shows that from the bottom of the well to the wellhead, from low to high, the absorption and attenuation effect of the thick loess is obvious, the amplitude (energy) gradually weakens, and the main frequency gradually decreases, which is of great significance for processing and interpretation work. Micro-logging results and spectrum and energy analysis are as follows: Figure 8 shown.

Claims

1. A bottom hole detector coupling device, comprising a detector, characterized in that: It also includes a detector cabin, in which the detector is fixedly installed, and the detector cabin is provided with a channel for leading out the detector signal line; the detector cabin itself forms a counterweight body, or a counterweight block is installed under the detector cabin to form a counterweight body together with the detector cabin.

2. The bottom hole detector coupling device according to claim 1, characterized in that: The detector cabin is a cylinder.

3. The bottom hole detector coupling device according to claim 2, characterized in that: A top cover is arranged above the detector cabin, and a hole is provided on the top cover for leading out the detector signal line.

4. The bottom hole detector coupling device according to claim 1, characterized in that: The detector comprises two detector cores, and the detector cores are fixed in the detector cabin through rubber pads.

5. The bottom hole detector coupling device according to claim 4, characterized in that: An insulating pad is installed between the two detector cores.

6. The bottom hole detector coupling device according to claim 1, characterized in that: The gap between the detector cabin and the detector is filled with waterproof material.

7. The bottom hole detector coupling device according to claim 3, characterized in that: A sealing ring is installed between the top cover and the detector cabin.

8. The bottom hole detector coupling device according to claim 3, characterized in that: The top cover is fixed on the detector cabin body by screw connection.

9. The bottom hole detector coupling device according to claim 3, characterized in that: A lifting ring is installed on the top cover, and the lifting ring is used for connecting with the cable.

10. The bottom hole detector coupling device according to claim 1, characterized in that: The detector cabin is made of pure steel.

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