Submarine sediment in-situ resistivity measuring device and measuring method

Abstract

The invention discloses a submarine sediment in-situ resistivity measurement device and a measurement method, and solves the technical problem of low measurement precision. The device comprises a supporting main body which is vertically arranged; the electrode system is arranged on the supporting main body in a sleeving manner; the upper shielding insulator is arranged on the supporting main body in a sleeving manner and is positioned above the electrode system; the lower shielding insulator is arranged on the supporting main body in a sleeving manner and is positioned below the electrode system; the communication connector is connected to the top and / or the bottom of the supporting body and used for being connected with an external sensor; the puncture cone is used for being connected to the bottom of the supporting body or connected to the bottom of an external sensor located below the supporting body. The influence of an external sensor on the current in the stratum can be reduced, so that the measurement precision of the measurement device is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of seabed sediment resistivity measurement, and in particular relates to a seabed sediment in-situ resistivity measurement device and a measurement method. Background Art

[0002] Resistivity is one of the most sensitive parameters for analyzing the physical state of seabed sediments. The resistivity value mainly depends on the composition and content of the pore fluid in the sediments, as well as the composition and structure of the sediments. Therefore, measuring the resistivity of sediments is of great significance for understanding marine sedimentation and engineering geological environment, detecting seabed mineral resources, etc. The in-situ resistivity measurement method completely maintains the physical properties and environmental state of the seabed sediments, and thus provides a more accurate evaluation of the physical properties of the sediments.

[0003] The in-situ resistivity measurement technology of seabed sediments is generally combined with a seabed drilling rig. The resistivity measurement device is penetrated into the seabed sediment using a drill pipe. The resistivity measurement device is provided with a Wenner electrode system or a Wenner-like electrode system, and the electrodes are generally arranged along the axial direction of the drill pipe to obtain the resistivity of the penetration profile.

[0004] At present, most resistivity in-situ measurement devices adopt independent designs, but in fact, other types of sensors are usually connected to the top or bottom of the resistivity in-situ measurement device. There is a certain degree of physical field coupling between the shells of these external sensors and the electrodes of the resistivity in-situ measurement device, that is, the metal shell of the external sensor will attract the current in the formation, and this influencing factor cannot be corrected by the scale of the measurement device. Therefore, when the resistivity in-situ measurement device is integrated into the static penetration system, the measurement accuracy is reduced and needs to be improved. Summary of the invention

[0005] In order to solve all or part of the above problems, the purpose of the present invention is to provide an in-situ resistivity measurement device and method for seabed sediments, which can reduce the influence of external sensors on the current in the formation and improve the measurement accuracy.

[0006] In a first aspect, the present invention provides a device for measuring in-situ resistivity of seabed sediments, comprising:

[0007] The supporting body is arranged vertically;

[0008] An electrode system, sleeved on the supporting body;

[0009] An upper shielding insulator is sleeved on the supporting body and is located above the electrode system;

[0010] A lower shielding insulator is sleeved on the supporting body and is located below the electrode system;

[0011] A communication connector connected to the top and / or bottom of the support body and used for connecting an external sensor;

[0012] The puncture cone is used to be connected to the bottom of the supporting body, or to be connected to the bottom of an external sensor located below the supporting body.

[0013] Optionally, the upper shielding insulator and the lower shielding insulator are respectively movably mounted on the supporting body, the communication connector at the upper end is threadedly connected to the top of the supporting body, and the upper shielding insulator is pressed and fixed to the top of the electrode system, the communication connector at the lower end and the threaded connection end of the puncture cone have the same size and can be threadedly connected to the bottom of the supporting body, respectively, and the lower shielding insulator is pressed and fixed to the bottom of the electrode system.

[0014] Optionally, the electrode system includes a current electrode, a first electrode, a second electrode and a return electrode which are sequentially sleeved on the support body from top to bottom, and intermediate insulators are respectively arranged between the current electrode and the first electrode, between the first electrode and the second electrode, and between the second electrode and the return electrode, and the three intermediate insulators are respectively sleeved on the support body.

[0015] Optionally, the electrode system further includes an upper insulator and a lower insulator respectively sleeved on the support body, the upper insulator is located between the current electrode and the upper shielding insulator, and the lower insulator is located between the return electrode and the lower shielding insulator.

[0016] Optionally, the supporting body includes a supporting shell and a data acquisition and transmission system, the supporting shell is cylindrical, and the data acquisition and transmission system is arranged in the supporting shell and connected to the communication connector.

[0017] Optionally, the supporting shell is made of metal material, and an insulating layer is provided on the outer surface of the supporting shell.

[0018] Optionally, the communication connector and the puncture cone are respectively made of high-strength stainless steel materials.

[0019] In a second aspect, the present invention provides a method for measuring the in-situ resistivity of seabed sediments, using the above-mentioned measuring device, comprising the following steps:

[0020] S1, connect the measuring device and the external sensor, and connect the measuring device or the external sensor to the bottom end of the probe;

[0021] S2, after the drill bit and drill collar have drilled to the original formation, the hydraulic device in the drill collar is used to push the probe rod out and allow the measuring device to penetrate into the formation. At this time, the formation resistivity is measured by the measuring device;

[0022] S3, using the hydraulic device in the drill collar to retract the probe rod and allow the measuring device to enter the drill collar;

[0023] S4, repeat S2-S3 in a loop to continuously carry out formation resistivity measurement of the next depth section.

[0024] Optionally, in S2, after the measuring device penetrates the formation, a low-frequency current I is emitted to the formation through the current electrode, and the low-frequency current I returns to the return electrode through the formation. At this time, the voltage difference V between the first electrode and the second electrode is measured, and the formation resistivity is calculated by the formula ρ=G·V / T, where G is the instrument constant.

[0025] Optionally, in S2, when the measuring device penetrates the formation, the current electrode can be controlled to continuously emit a low-frequency current I to the formation, so that the measuring device can continuously measure the formation resistivity at different depths.

[0026] It can be seen from the above technical scheme that the device and method for measuring the in-situ resistivity of seabed sediments provided by the present invention have the following advantages:

[0027] The device achieves insulation isolation between the electrode system and the external sensor by setting the upper shielding insulator and the lower shielding insulator, effectively reducing the influence of the external sensor on the current in the formation, thereby improving the measurement accuracy. At the same time, the device can replace the upper shielding insulator and the lower shielding insulator of different lengths, so that the staff can select the upper shielding insulator and the lower shielding insulator of the corresponding length according to the length and plate of the external sensor to ensure that the formation current will not be attracted by the metal shell of the external sensor, thereby ensuring the measurement accuracy of the measuring device.

[0028] Other features and advantages of the present invention will be set forth in the description which follows. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The accompanying drawings are used to provide a further understanding of the technical solution of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the technical solution of the present invention and do not constitute a limitation on the technical solution of the present invention.

[0030] Figure 1 It is a schematic diagram of the overall structure of an embodiment of the present invention;

[0031] Figure 2 It is a structural schematic diagram of an embodiment of the present invention, showing the state of measurement mode 1;

[0032] Figure 3It is a schematic diagram of the structure of an embodiment of the present invention, showing the state of measurement mode 2;

[0033] Figure 4 It is a schematic diagram of the structure of an embodiment of the present invention, showing the state of measurement mode three;

[0034] Figure 5 Schematic diagram of the use status of an embodiment of the present invention.

[0035] Description of reference numerals:

[0036] 1. Support body; 11. Support shell; 12. Data acquisition and transmission system; 2. Upper shielding insulator; 3. Electrode system; 31. Upper insulator; 32. Current electrode; 33. First electrode; 34. Second electrode; 35. Return electrode; 36. Lower insulator; 37. Intermediate insulator; 4. Lower shielding insulator; 5. Communication connector; 6. Puncture cone. DETAILED DESCRIPTION

[0037] To make the purpose, technical solution and advantages of the present invention more clear, the embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be noted that the embodiments and features in the embodiments of the present invention can be combined with each other arbitrarily without conflict.

[0038] like Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 An embodiment of the present invention is shown, in which an in-situ resistivity measuring device for seabed sediments is disclosed, comprising a vertically arranged support body 1, on which an upper shielding insulator 2, an electrode system 3 and a lower shielding insulator 4 are sequentially sleeved from top to bottom, and the upper shielding insulator 2 and the lower shielding insulator 4 are respectively abutted against the electrode system 3.

[0039] A communication connector 5 is provided at the top and / or bottom of the support body 1, and the external sensor can be connected to the communication connector 5. The measuring device also includes a puncture cone 6, which is used to be connected to the bottom of the support body 1, or to the bottom of the external sensor located below the support body 1. In this embodiment, the communication connector 5 and the puncture cone 6 are respectively made of high-strength stainless steel materials, and the communication connector contains a cable adapter to transmit measurement data.

[0040] In this embodiment, the measuring device has three measuring modes according to the position of the external sensor. The specific measuring modes are as follows:

[0041] Measurement mode 1:

[0042] like Figure 2As shown, only one set of external sensors is provided, and the sensors are located above the support body 1. In this measurement mode, only one communication connector 5 is provided, and the communication connector 5 is connected to the top of the support body 1, and the puncture cone 6 is directly connected to the bottom of the support body 1. In this measurement mode, the bottom of the sensor is connected to the communication connector 5, and the top is connected to the conversion connector in the probe rod.

[0043] Measurement mode 2:

[0044] like Figure 3 As shown, only one set of external sensors is provided, and the sensors are located below the support body 1. In this measurement mode, two communication connectors 5 are provided, one of which is connected to the top of the support body 1, and the top of the communication connector 5 is connected to the conversion connector in the probe rod, and the other communication connector 5 is connected to the bottom of the support body 1, and the sensor is connected to the bottom of the communication connector 5, and the puncture cone 6 is connected to the bottom of the sensor.

[0045] Measurement mode three:

[0046] like Figure 4 As shown, two groups of external sensors are provided, one group of sensors is located above the support body 1, and the other group of sensors is located below the support body 1. In this measurement mode, two communication connectors 5 are provided, one of which is connected to the top of the support body 1, and the bottom of one group of sensors is connected to the communication connector 5, and the top is connected to the conversion connector in the probe rod, and the other communication connector 5 is connected to the bottom of the support body 1, and the sensor is connected to the bottom of the communication connector 5, and the puncture cone 6 is connected to the bottom of the sensor.

[0047] The number and installation positions of the external sensors in this embodiment can be selected according to the actual needs of the staff, thereby improving the adaptability of use, so that the measuring device can adapt to various testing needs and improve practicality.

[0048] The in-situ resistivity measuring device for seabed sediments in this embodiment realizes insulation isolation between the electrode system 3 and the external sensor through the upper shielding insulator 2 and the lower shielding insulator 4, effectively reducing the influence of the external sensor on the current in the formation, thereby improving the measurement accuracy.

[0049] In one embodiment, Figure 1 As shown, the upper shielding insulator 2 is movably mounted on the supporting body 1, and the communication connector 5 located at the upper end is threadedly connected to the top of the supporting body 1, and the communication connector 5 presses and fixes the upper shielding insulator 2 to the top of the electrode system 3, so that the upper shielding insulator 2 can be replaced with different lengths.

[0050] In one embodiment, Figure 1As shown, the lower shielding insulator 4 is movably mounted on the supporting body 1, and the threaded connection ends of the communication connector 5 and the puncture cone 6 located at the lower end are of the same size, that is, the communication connector 5 and the puncture cone 6 can be threadedly connected to the bottom of the supporting body 1 respectively, and the communication connector 5 or the puncture cone 6 presses and fixes the lower shielding insulator 4 to the bottom of the electrode system 3, so that the upper shielding insulator 2 can be replaced with different lengths.

[0051] That is, when measuring mode 1 is adopted, the puncture cone 6 presses and fixes the lower shielding insulator 4 to the bottom of the electrode system 3 , and when measuring modes 2 and 3 are adopted, the communication connector 5 presses and fixes the lower shielding insulator 4 to the bottom of the electrode system 3 .

[0052] Since the measuring device can replace the upper shielding insulator 2 and the lower shielding insulator 4 of different lengths, the staff can select the upper shielding insulator 2 and the lower shielding insulator 4 of corresponding lengths according to the length and diagram of the external sensor to ensure that the formation current will not be attracted by the metal casing of the external sensor, thereby ensuring the measurement accuracy of the measuring device.

[0053] In one embodiment, Figure 1 As shown, the electrode system 3 includes an upper insulator 31, a current electrode 32, an intermediate insulator 37, a first electrode 33, an intermediate insulator 37, a second electrode 34, an intermediate insulator 37, a return electrode 35 and a lower insulator 36 which are fixedly mounted on the support body 1 from top to bottom, and adjacent ones are in contact with each other.

[0054] Since the intermediate insulator 37 is arranged between two adjacent electrodes, the insulation isolation between the two adjacent electrodes is realized, the current is prevented from flowing between the two adjacent electrodes, and the magnetic field coupling effect between the electrodes is reduced, thereby improving the measurement accuracy. At the same time, the upper insulator 31 and the lower insulator 36 can also increase the insulation isolation length between the electrode and the external sensor, further reducing the attraction effect of the external sensor on the current in the formation, so as to ensure the measurement accuracy.

[0055] In this embodiment, the upper insulator 31, the current electrode 32, the middle insulator 37, the first electrode 33, the middle insulator 37, the second electrode 34, the middle insulator 37, the return electrode 35 and the lower insulator 36 can be fixed on the support body 1 by press-fitting, and a sealing ring is provided between the adjacent two to ensure the sealing effect. Of course, the upper insulator 31, the current electrode 32, the middle insulator 37, the first electrode 33, the middle insulator 37, the second electrode 34, the middle insulator 37, the return electrode 35 and the lower insulator 36 can also be fixed on the support body 1 by threaded connection, and the adjacent two can also be connected by additional stepped threads to improve the connection stability.

[0056] In this embodiment, the current electrode 32, the return electrode 35, the first electrode 33 and the second electrode 34 are respectively made of high-strength wear-resistant, corrosion-resistant and oxidation-resistant metal materials, and the intermediate insulator 37, the upper insulator 31, the lower insulator 36, the upper shielding insulator 2 and the lower shielding insulator 4 are respectively made of high-strength wear-resistant insulating materials.

[0057] In one embodiment, Figure 1 As shown, the support body 1 includes a support shell 11 and a data acquisition and transmission system 12. The support shell 11 is cylindrical and made of high-strength steel. The data acquisition and transmission system 12 is arranged in the support shell 11 and connected to the communication connector 5. At the same time, the support shell 11 is made of metal material, and an insulating layer is provided on the outer surface of the support shell 11 to achieve insulation isolation between the support shell 11 and the electrode.

[0058] In this embodiment, the data acquisition and transmission system 12 includes components such as a power supply module, a sinusoidal signal generator, a voltage-controlled current source, a voltage measurement module, a feedback logic control module, a current measurement module, and a communication cable. This is the prior art and will not be elaborated on here.

[0059] like Figure 5 As shown, this embodiment also discloses a method for measuring the in-situ resistivity of seabed sediments. Using the above-mentioned measuring device, the measuring method includes the following steps:

[0060] S1, connect the measuring device and the external sensor, and connect the measuring device or the external sensor to the bottom end of the probe rod.

[0061] S2, start the drill bit, and after the drill bit and the drill collar drill to the original formation, use the hydraulic device in the drill collar to push the probe rod out and allow the measuring device to penetrate into the formation. At this time, the formation resistivity is measured by the measuring device.

[0062] S3, use the hydraulic device in the drill collar to retract the probe rod and allow the measuring device to enter the drill collar.

[0063] S4, repeat S2-S3 in a loop to continuously carry out formation resistivity measurement of the next depth section.

[0064] In S2, after the measuring device penetrates the formation, a low-frequency current I is emitted to the formation through the current electrode 32, and the low-frequency current I returns to the return electrode 35 through the formation. At this time, the voltage difference V between the first electrode 33 and the second electrode 34 is measured, and the formation resistivity is calculated by the formula ρ=G·V / T, where G is the instrument constant.

[0065] In S2, when the measuring device penetrates the formation, the current electrode 32 can be controlled to continuously emit a low-frequency current I to the formation, so that the measuring device can continuously measure the formation resistivity at different depths. The staff can judge the composition and structure of the formation sediments and other information through the real-time change curve of the resistivity.

[0066] As can be seen from the above, the measuring device measures the formation resistivity by measuring the voltage at two points in the formation through which the current passes, and the two ends of the electrode system 3 are provided with a shielding insulator of variable length that can be flexibly disassembled. When the measuring device is connected to the seabed drilling rig and integrated into the static penetration system, high-precision measurement of deep-sea seabed sediments (water depth>2000m, seabed sediments 0-300m) can be achieved. Compared with the existing in-situ resistivity measuring device, the present invention can effectively reduce the influence of the external sensor on the current in the formation, thereby improving the measurement accuracy, and further providing reliable data guarantee for the staff.

[0067] It should be noted that, unless otherwise specified, the technical terms or scientific terms used in the present invention should have the common meanings understood by those skilled in the art to which the present invention belongs.

[0068] In addition, the terms "first", "second", etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. In the description of the present invention, the meaning of "plurality" is more than two, unless otherwise clearly and specifically defined.

[0069] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and specification of the present invention. In particular, as long as there is no structural conflict, the various technical features mentioned in each embodiment can be combined in any way. The present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A device for measuring the in-situ resistivity of seabed sediments, characterized in that: include: A supporting body (1) is arranged vertically; An electrode system (3) is sleeved on the supporting body (1); An upper shielding insulator (2) is sleeved on the supporting body (1) and is located above the electrode system (3); A lower shielding insulator (4) is sleeved on the supporting body (1) and is located below the electrode system (3); A communication connector (5), connected to the top and / or bottom of the support body (1) and used for connecting an external sensor; The puncture cone (6) is used to be connected to the bottom of the supporting body (1), or to be connected to the bottom of an external sensor located below the supporting body (1).

2. The measuring device according to claim 1, characterized in that The upper shielding insulator (2) and the lower shielding insulator (4) are movably mounted on the supporting body (1), respectively; the communication connector (5) located at the upper end is threadedly connected to the top of the supporting body (1), and the upper shielding insulator (2) is pressed and fixed to the top of the electrode system (3); the threaded connection ends of the communication connector (5) and the puncture cone (6) located at the lower end have the same size and can be threadedly connected to the bottom of the supporting body (1), respectively, and the lower shielding insulator (4) is pressed and fixed to the bottom of the electrode system (3).

3. The measuring device according to claim 1, characterized in that The electrode system (3) comprises a current electrode (32), a first electrode (33), a second electrode (34) and a return electrode (35) which are sequentially sleeved on the support body (1) from top to bottom, and intermediate insulators (37) are respectively arranged between the current electrode (32) and the first electrode (33), between the first electrode (33) and the second electrode (34), and between the second electrode (34) and the return electrode (35), and the three intermediate insulators (37) are respectively sleeved on the support body (1).

4. The measuring device according to claim 3, characterized in that The electrode system (3) further comprises an upper insulator (31) and a lower insulator (36) respectively sleeved on the support body (1), wherein the upper insulator (31) is located between the current electrode (32) and the upper shielding insulator (2), and the lower insulator (36) is located between the return electrode (35) and the lower shielding insulator (4).

5. The measuring device according to claim 1, characterized in that The support body (1) comprises a support shell (11) and a data acquisition and transmission system (12); the support shell (11) is cylindrical; the data acquisition and transmission system (12) is arranged in the support shell (11) and is connected to the communication connector (5).

6. The measuring device according to claim 5, characterized in that The supporting shell (11) is made of metal material, and an insulating layer is provided on the outer surface of the supporting shell (11).

7. The measuring device according to claim 1, characterized in that The communication connector (5) and the puncture cone (6) are respectively made of high-strength stainless steel material.

8. A method for measuring in-situ resistivity of seabed sediments, using the measuring device according to any one of claims 1 to 7, characterized in that: The steps include: S1, connect the measuring device and the external sensor, and connect the measuring device or the external sensor to the bottom end of the probe; S2, after the drill bit and drill collar have drilled to the original formation, the hydraulic device in the drill collar is used to push the probe rod out and allow the measuring device to penetrate into the formation. At this time, the formation resistivity is measured by the measuring device; S3, using the hydraulic device in the drill collar to retract the probe rod and allow the measuring device to enter the drill collar; S4, repeat S2-S3 in a loop to continuously carry out formation resistivity measurement of the next depth section.

9. The measuring method according to claim 8, characterized in that: In S2, after the measuring device penetrates the formation, a low-frequency current I is emitted to the formation through the current electrode (32), and the low-frequency current I returns to the return electrode (35) through the formation. At this time, the voltage difference V between the first electrode (33) and the second electrode (34) is measured, and the formation resistivity is calculated by the formula ρ=G·V / T, where G is the instrument constant.

10. The measuring method according to claim 9, characterized in that: In S2, when the measuring device penetrates the formation, the current electrode (32) can be controlled to continuously emit a low-frequency current I to the formation, so that the measuring device can continuously measure the formation resistivity at different depths.

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