Underground detector suitable for surface attenuation survey

Abstract

The utility model provides an underground geophone suitable for surface attenuation investigation. The underground geophone comprises an explosion rod conveying frame, an arc-shaped connecting rod, a lengthened tail cone and a ground geophone. One end of the arc-shaped connecting rod is fixedly connected to the bottom of the explosion rod conveying frame, and the other end is fixedly connected to the top of the lengthened caudal vertebra; the ground detector comprises a detector body, a signal transmission line and a tail cone, and the tail end of the tail cone is fixedly connected with the top of the lengthened tail cone. The explosion rod conveying frame is connected with the explosion rod and the steel wire rope to control the well descending stability of the detector, and inclination and suspension are avoided; the lengthened tail cone can be firmly inserted into the stratum, and accurate well bottom signals can be better collected; after waveform collection of the underground detector is finished, the detector can be recycled through the steel wire rope, and the underground detector is already applied to actual production and achieves a good effect.

Description

Technical Field

[0001] The utility model relates to the technical field of exploration equipment, in particular to a downhole geophone suitable for surface attenuation investigation. Background Art

[0002] In seismic exploration, the attenuation of seismic signals by near-surface strata will affect stratum imaging. Since near-surface strata are loosely deposited, the degree of signal attenuation is even greater than that of thicker diagenetic strata. In response to this technical problem, in recent years, technical personnel in this field have explored the use of micro-logging surveys to measure the attenuation of near-surface strata to signals of different frequencies or to calculate the earth's quality factor Q value to achieve seismic imaging of near-surface strata. The main observation methods include single-well micro-logging, double-well micro-logging, and multi-well micro-logging. Double-well micro-logging and multi-well micro-logging use ground and bottom-of-hole buried detectors to calculate the attenuation by the difference in signals received on the ground and at the bottom of the well. This requires the detector to accurately receive the signal, which is a major challenge for the burial of the bottom-of-hole detector.

[0003] At present, in the process of micro-logging survey, ordinary ground geophones are generally used as downhole geophones. However, due to the influence of the underground rock and soil properties, it is difficult for ordinary ground geophones to couple with the bottom rock mass. It is difficult to collect signals with regular first arrival waveforms by directly using ordinary ground geophones as downhole geophones. When burying geophones underground, wooden poles are usually used to push ordinary ground geophones to the bottom of the well, which can easily cause the geophones to be suspended in the air. In addition, when drilling near the surface, due to the loose sedimentation, mud and sand precipitation is easily formed at the bottom of the well, making it difficult for the geophone to couple with the formation, resulting in weak received signal strength and low frequency, which cannot be used to calculate the attenuation factor.

[0004] In summary, it can be seen that there is an urgent need to provide a downhole detector that can solve the defects in downhole signal acquisition accuracy, facilitate downhole operation, has good coupling with the formation, and is suitable for surface attenuation investigation. Utility Model Content

[0005] In view of this, the utility model provides a downhole geophone suitable for surface attenuation investigation, which is improved on the basis of a conventional ground geophone to obtain a downhole geophone that is easy to operate and controllable in the well and well coupled with the formation.

[0006] In a first aspect, a downhole geophone suitable for surface attenuation investigation, the downhole geophone comprising an explosive rod conveying frame, an arc-shaped connecting rod, an extended tail cone and a ground geophone;

[0007] One end of the arc-shaped connecting rod is fixedly connected to the bottom of the explosive rod conveying frame, and the other end is fixedly connected to the top of the lengthened tail vertebrae;

[0008] The ground detector comprises a detector body, a signal transmission line and a tail vertebra, and the end of the tail vertebra is fixedly connected to the top of the lengthened tail vertebra.

[0009] In a possible implementation, the explosive rod conveying frame includes an upper metal ring, a lower metal ring, a wire rope connecting ring and an upright connecting rod;

[0010] The upper metal ring and the lower metal ring are two metal rings of the same size, the outer sides of the upper metal ring and the lower metal ring are connected to the upright connecting rod, and the radial directions of the upper metal ring and the lower metal ring are perpendicular to the upright connecting rod, so that the upper metal ring and the lower metal ring are arranged on the upright connecting rod in parallel and coaxial manner; the upper metal ring and the lower metal ring are located directly above the detector body;

[0011] The wire rope connecting ring is fixedly connected to the top end of the upright connecting rod.

[0012] In a possible implementation, the upper metal ring and the lower metal ring are 10 centimeters apart, and the lower metal ring and the top surface of the detector body are 10 centimeters apart.

[0013] In a possible implementation, the inner diameters of the upper metal ring and the lower metal ring are equal to the diameter of the explosive rod.

[0014] In a possible implementation, the inner diameter of the wire rope connecting ring is 1 cm.

[0015] In a possible implementation, the central axes of the upper metal ring and the lower metal ring are in the same straight line as the central axis of the detector body, the tail vertebra of the ground detector, and the extended tail vertebra.

[0016] In a possible implementation, the explosive rod conveying frame, the arc-shaped connecting rod, the lengthened tail vertebrae and the tail vertebrae are all connected by welding.

[0017] In a possible implementation, the explosive rod conveying frame, the arc-shaped connecting rod and the lengthened tail vertebrae are all made of steel bars.

[0018] In a possible implementation, the length of the extended coccyx is 10 centimeters, and it has a conical structure that is thick at the top and thin at the bottom.

[0019] Compared with the prior art, the following technical effects are achieved in the embodiments of the present invention:

[0020] (1) The downhole geophone suitable for surface attenuation investigation of the utility model can be made by modifying a conventional ground geophone, and is easy to manufacture;

[0021] (2) The utility model controls the stability of the detector when it is lowered into the well by using the explosive rod and the wire rope, which will not cause the detector to tilt or hang in the air in the well;

[0022] (3) The utility model provides an arc-shaped connecting rod, so that after the downhole geophone reaches the bottom of the well, the external force can be transmitted through the explosive rod, so that the downhole geophone is well coupled with the downhole formation, thereby accurately receiving the bottom hole signal;

[0023] (4) The bottom of the downhole geophone of the utility model is provided with an extended tail cone, which can be firmly inserted into the formation, avoiding the suspension or tilt of the geophone at the bottom of the well, especially when approaching the top of the high-speed layer, which is more conducive to collecting accurate bottom hole signals;

[0024] (5) After the waveform collection of the downhole geophone of the utility model is completed, the geophone can be recovered by the wire rope.

[0025] The downhole geophone of the utility model suitable for surface attenuation investigation has been applied in actual production and achieved good results. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0027] Figure 1 A schematic diagram of the overall structure of a downhole geophone suitable for surface attenuation investigation provided by an embodiment of the utility model;

[0028] Figure 2 A schematic diagram of the structure of an explosive rod conveying frame of a downhole geophone suitable for surface attenuation investigation provided by an embodiment of the utility model;

[0029] Figure 3 A schematic diagram of the structure of an arc-shaped steel bar connecting rod of a downhole geophone suitable for surface attenuation investigation provided by an embodiment of the utility model;

[0030] Figure 4 A comparison diagram of downhole use effects of a downhole geophone suitable for surface attenuation investigation provided by an embodiment of the utility model and an ordinary geophone; wherein Figure (a) is a signal waveform received by an ordinary ground geophone, and Figure (b) is a signal waveform received by a downhole geophone suitable for surface attenuation investigation provided by an embodiment of the utility model;

[0031] Among them, 1-explosive rod conveying frame; 2-arc-shaped connecting rod; 3-lengthened tail vertebra; 4-ground detector; 101-upper metal ring; 102-lower metal ring; 103-wire rope connecting ring; 104-upright connecting rod; 401-detector body; 402-signal transmission line; 403-tail vertebra. DETAILED DESCRIPTION

[0032] In order to better understand the technical solution of the present application, the embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0033] It should be clear that the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0034] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms "a", "said" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0035] It should be understood that the term "and / or" used in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0036] See also Figure 1 , is a schematic diagram of the overall structure of a downhole geophone suitable for surface attenuation investigation provided by an embodiment of the utility model. Figure 1 As shown, the downhole geophone includes an explosive rod conveying frame 1, an arc-shaped connecting rod 2, an extended tail vertebra 3 and a ground geophone 4.

[0037] One end of the arc-shaped connecting rod 2 is fixedly connected to the bottom of the explosive rod conveying frame 1, and the other end is fixedly connected to the top of the lengthened tail vertebra 3;

[0038] The ground detector 4 includes a detector body 401, a signal transmission line 402 and a tail cone 403. The signal transmission line 402 is connected to the detector body 401 to achieve signal transmission; the tail cone 403 is arranged at the bottom of the detector body 401, and the end of the tail cone 403 is fixedly connected to the top of the lengthened tail cone 3.

[0039] Furthermore, the fixed connection between the explosive rod conveying frame 1, the arc-shaped connecting rod 2, the lengthened tail vertebra 3 and the ground detector 4 is welding.

[0040] The explosive rod conveying frame 1 is used to fix and connect the explosive rod so as to convey the downhole geophone suitable for surface attenuation survey to the downhole through the explosive rod. Figure 2 , is a schematic diagram of the structure of an explosive rod conveyor frame of a downhole geophone suitable for surface attenuation investigation provided by an embodiment of the utility model. Figure 2 As shown, the explosive rod conveying frame 1 includes an upper metal ring 101, a lower metal ring 102, a wire rope connecting ring 103 and an upright connecting rod 104.

[0041] The upper metal ring 101 and the lower metal ring 102 are two metal rings of the same size, and the outer sides of the upper metal ring 101 and the lower metal ring 102 are fixedly connected to the side of the upright connecting rod 104, and the radial directions of the two are perpendicular to the upright connecting rod 104, so that the upper metal ring 101 and the lower metal ring 102 are arranged on the upright connecting rod 104 in parallel and coaxial manner.

[0042] Preferably, the inner diameters of the upper metal ring 101 and the lower metal ring 102 are equal to or slightly larger than the diameter of the explosive rod, so as to facilitate the fixing of the explosive rod.

[0043] Furthermore, the upper metal ring 101 and the lower metal ring 102 are 10 cm apart, and the lower metal ring 102 and the top surface of the detector body 401 are 10 cm apart. If the distance is too small, the explosive rod may easily slide off the conveyor frame, and the metal ring will not play a restraining role.

[0044] Furthermore, the upper metal ring 101 and the lower metal ring 102 are located directly above the detector body 401, so that the upper metal ring 101, the lower metal ring 102 and the detector body 401 are coaxially arranged, so that the bottom of the explosive rod is aligned with the center of gravity of the ground detector 4. When the detector reaches the bottom of the well, the external force can be transmitted through the explosive rod, so that the detector is tightly coupled with the underground formation.

[0045] The wire rope connecting ring 103 is fixedly connected to the top of the upright connecting rod 104, so as to control the stability of the detector when it is lowered into the well through the wire rope and facilitate the recycling of the detector.

[0046] Furthermore, the inner diameter of the steel wire rope connecting ring 103 is 1 cm.

[0047] See also Figure 3 , is a schematic diagram of the structure of an arc-shaped steel bar connecting rod of a downhole geophone suitable for surface attenuation investigation provided by an embodiment of the utility model. Figure 3 As shown, the arc-shaped connecting rod 2 connects the explosive rod conveying frame 1 and the lengthened tail vertebra 3 into a whole. The arc-shaped steel bar connecting rod 2 is more conducive to reducing friction resistance than other shapes (such as rectangle, etc.).

[0048] The curvature of the arc-shaped connecting rod 2 can ensure that the central axes of the upper metal ring 101 and the lower metal ring 102 are in the same straight line with the central axis of the detector body 401 , the tail vertebra 403 of the ground detector and the extended tail vertebra 3 .

[0049] Furthermore, the arc-shaped connecting rod 2 does not contact the detector body 401 .

[0050] Furthermore, the arc-shaped connecting rod 2 and the signal transmission line 402 are respectively located on two sides of the detector body 402 to avoid affecting signal transmission.

[0051] The starting point of the lengthened tail vertebra 3 is connected to the end point of the tail vertebra 403 of the ground detector 4 by welding. Through the welding point, the explosive rod conveying frame 1 and the lengthened tail vertebra 3 are fixedly connected to the ground detector 4 as a whole.

[0052] Preferably, the length of the extended tail vertebra 3 is 10 cm, so that the detector can be firmly driven into the formation without floating or tilting in the well, especially when approaching the top of the high-speed layer, which is more conducive to collecting accurate bottom hole signals.

[0053] It should be noted that the ground detector 4 in the present invention is a conventional ground detector. When a person skilled in the art manufactures a downhole detector suitable for surface attenuation investigation according to the technical solution of the present invention, a conventional ground detector can be selected according to actual needs. The present invention does not elaborate on the structure and specific composition of the ground detector. Similarly, the power supply method of the ground detector, the connection method between the signal transmission line and the detector body, and the specific structure and composition of the detector body are all common knowledge in the art, and the present invention does not elaborate on them.

[0054] Based on the above technical solution, the manufacturing steps of a downhole geophone suitable for surface attenuation investigation are as follows:

[0055] Select a conventional ground detector according to actual needs;

[0056] Make two metal rings of equal size, and the diameter of the ring hole is consistent with the diameter of the explosive rod, so as to facilitate the fixed connection between the explosive rod and the detector;

[0057] Making an extended tail vertebra, the extended tail vertebra is a conical structure of 10 cm long, thick at the top and thin at the bottom, and the bottom of the tail vertebra is as thin as possible to reduce friction resistance and facilitate insertion into a deeper position of the stratum;

[0058] A vertical connecting rod is made, wherein the vertical connecting rod is 15 cm long, and two metal rings are welded to the vertical connecting rod from the same side with a spacing of 10 cm to form an explosive rod conveying frame;

[0059] A wire rope connection ring with a hole diameter of 1 cm is welded on the top of the vertical connecting rod to facilitate the control of the stability of the detector when it is lowered into the well through the wire rope and to realize the recycling of the detector;

[0060] Make an arc-shaped connecting rod, the arc span of which is the distance between the metal ring under the explosive rod conveyor frame and the detector body plus the length of the ground detector. The arc-shaped connecting rod needs to include the detector, and the distance from the highest point of the arc to the center of the detector cover needs to be greater than 1 / 2 of the side length of the detector cover;

[0061] Weld the arc-shaped connecting rod to the explosive rod conveying frame and the extended tail cone to ensure that the center of the lower metal ring is aligned with the center of the detector body. In this way, the external force can be well transmitted to the tail cone and the extended tail cone of the detector through the explosive rod, which is convenient for controlling the coupling between the detector and the formation;

[0062] Weld the top of the extended tail vertebrae to the bottom of the tail vertebrae of the conventional ground detector. The signal transmission line of the ground detector is located on the opposite side of the arc-shaped connecting rod to avoid affecting the signal transmission. Make sure that the tail vertebrae of the ground detector is in a straight line with the extended tail vertebrae, and the center of the metal ring of the explosive rod conveying frame is located directly above the center of the detector body. In addition, the distance between the lower metal ring and the detector body is 10 cm, not too close, otherwise the explosive rod will easily slip out of the metal ring, and the lower metal ring will not play a restraining role on the explosive rod.

[0063] The utility model is a downhole geophone suitable for surface attenuation investigation. The stability of the geophone can be controlled by the downhole explosive rod and the wire rope at the same time, and it will not be skewed or suspended. After the geophone reaches the bottom of the well, the external force is transmitted through the explosive rod, which can better couple the geophone with the downhole formation, so as to receive accurate bottom hole signals. After the acquisition is completed, the geophone can be recovered by the wire rope. The utility model downhole geophone has been applied in actual production and achieved good results.

[0064] See also Figure 4 , is a comparison diagram of the downhole use effects of a downhole geophone suitable for surface attenuation investigation provided by the embodiment of the utility model and a common geophone. Figure 4 As shown, the second waveform from the left in Figure (a) is the signal waveform received by an ordinary ground geophone. It can be seen that the signal received by the ordinary ground geophone has unclear take-off and first arrival waveforms, and the received signal amplitude is weak; the second waveform from the left in Figure (b) is the signal waveform received by a downhole geophone suitable for surface attenuation investigation provided by an embodiment of the utility model. It can be seen that the signal received by a downhole geophone suitable for surface attenuation investigation provided by the utility model has a crisp take-off, clear first arrival waveform, strong amplitude and high frequency. The signal received downhole can obtain accurate formation attenuation information relative to the attenuated signal on the ground through the frequency shift method.

[0065] The above is only a specific implementation of the present application. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. The protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A downhole geophone suitable for surface attenuation investigation, characterized in that: The downhole geophone comprises an explosive rod conveying frame (1), an arc-shaped connecting rod (2), an extended tail cone (3) and a ground geophone (4); One end of the arc-shaped connecting rod (2) is fixedly connected to the bottom of the explosive rod conveying frame (1), and the other end is fixedly connected to the top of the lengthened tail vertebra (3); The ground detector (4) comprises a detector body (401), a signal transmission line (402) and a tail vertebra (403), and the end of the tail vertebra (403) is fixedly connected to the top of the lengthened tail vertebra (3).

2. A downhole geophone suitable for surface attenuation investigation according to claim 1, characterized in that: The explosive rod conveying frame (1) comprises an upper metal ring (101), a lower metal ring (102), a steel wire rope connecting ring (103) and an upright connecting rod (104); The upper metal ring (101) and the lower metal ring (102) are two metal rings of the same size, the outer sides of the upper metal ring (101) and the lower metal ring (102) are fixedly connected to the side of the upright connecting rod (104), and the radial directions of the upper metal ring (101) and the lower metal ring (102) are perpendicular to the upright connecting rod (104), so that the upper metal ring (101) and the lower metal ring (102) are arranged on the upright connecting rod (104) in a vertically parallel and coaxial manner; the upper metal ring (101) and the lower metal ring (102) are located directly above the detector body (401); The steel wire rope connecting ring (103) is fixedly connected to the top end of the upright connecting rod (104).

3. A downhole geophone suitable for surface attenuation investigation according to claim 2, characterized in that: The upper metal ring (101) and the lower metal ring (102) are 10 centimeters apart, and the lower metal ring (102) and the top surface of the detector body (401) are 10 centimeters apart.

4. A downhole geophone suitable for surface attenuation investigation according to claim 2, characterized in that: The inner diameters of the upper metal ring (101) and the lower metal ring (102) are equal to the diameter of the explosive rod.

5. A downhole geophone suitable for surface attenuation investigation according to claim 2, characterized in that: The inner diameter of the steel wire rope connecting ring (103) is 1 cm.

6. A downhole geophone suitable for surface attenuation investigation according to claim 2, characterized in that: The central axes of the upper metal ring (101) and the lower metal ring (102) are in the same straight line as the central axis of the detector body (401), the tail vertebra (403) of the ground detector, and the extended tail vertebra (3).

7. A downhole geophone suitable for surface attenuation investigation according to claim 1, characterized in that: The explosive rod conveying frame (1), the arc-shaped connecting rod (2), the lengthened tail vertebra (3) and the tail vertebra (403) are all connected by welding.

8. A downhole geophone suitable for surface attenuation investigation according to claim 1, characterized in that: The explosive rod conveying frame (1), the arc-shaped connecting rod (2) and the lengthened tail vertebrae (3) are all made of steel bars.

9. A downhole geophone suitable for surface attenuation investigation according to claim 1, characterized in that: The length of the lengthened caudal vertebra (3) is 10 centimeters, and it is in a conical structure that is thick at the top and thin at the bottom.

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