CN111796003A - A kind of core resistivity measuring device and its measuring method - Google Patents

Abstract

The invention discloses a core resistivity measuring device and a measuring method thereof, and relates to the technical field of core resistivity measurement, wherein the core resistivity measuring device comprises a measuring instrument, a fixed frame, a pressure loading device fixed on the fixed frame, an upper base and a lower base for clamping a core, grooves for fixing the end part of the core are arranged on the upper base and the lower base, a pressure sensor, an electrode plate and a sponge gasket soaked by electrolyte solution are sequentially stacked between the end part of the core and the bottom surface of the groove, the sponge gasket is contacted with the end part of the core, and the pressure sensor and the electrode plate are electrically connected with the measuring instrument; according to the invention, the sponge gasket soaked by the electrolyte solution can ensure good contact between the electrode plate and the rock core, and prevent the larger contact resistance between the electrode plate and the rock core from influencing the experimental result; and through setting up the sponge gasket, when the installation, the sponge gasket can play the effect of buffering, and the impact when preventing the installation destroys pressure sensor.

Description

A kind of core resistivity measuring device and its measuring method

technical field

The invention relates to the technical field of core resistivity measurement, in particular to a core resistivity measurement device and a measurement method thereof.

Background technique

With the continuous consumption of mineral resources, resources in the shallow part are basically explored and developed, and the exploration and development of mineral resources are currently carried out in the deep part. Electromagnetic exploration technology is an important technical means for the exploration of deep mineral resources. The technical premise of electromagnetic exploration is to fully grasp the resistivity distribution characteristics of deep rocks. Taking out the core by drilling and measuring the resistivity parameters is the main method to understand the deep rock resistance distribution. At present, the main measurement method of core resistivity is based on the symmetrical quadrupole method. The resistivity of the core is measured under normal pressure. However, after the core is taken out from the deep underground, the pressure environment in which it is located changes, and the measured resistivity value cannot represent the underground. True resistivity of deep rocks.

Therefore, the present invention proposes a core resistivity tester that can load pressure in real time, and achieves the purpose of measuring the true resistance of deep cores by changing the pressure during measurement.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a core resistivity measuring device and a measuring method thereof, so as to solve the problems existing in the above-mentioned prior art, and can accurately measure the resistivity of the core under different axial pressures, and has a simpler structure and more convenient operation. convenient.

In order to achieve the above purpose, the present invention provides the following solutions: The present invention provides a core resistivity measurement device, including a measuring instrument, a fixed frame, a pressure loading device fixed on the fixed frame, and an upper base for holding the core. , a lower base, the upper base is fixed on the movable end of the pressure loading device, the lower base is fixed at the end of an adjustable movable part, and the adjustable movable part can drive the lower base to move axially ; The upper base and the lower base are both provided with grooves for fixing the end of the rock core, and the two grooves are coaxially arranged;

Between the end of the rock core and the bottom surface of the groove, a pressure sensor, an electrode sheet and a sponge pad soaked with an electrolyte solution are stacked in sequence, and the sponge pad is in contact with the end of the rock core, and the pressure Both the sensor and the electrode sheet are electrically connected to the measuring instrument.

Preferably, the upper base and the movable end of the pressure loading device are connected by connecting bolts, and the upper base and the movable end of the pressure loading device are coaxially arranged.

Preferably, the adjustable movable part is a tightening bolt, and the tightening bolt is fixed on the fixed frame in a threaded manner.

Preferably, the pressure loading device is a telescopic oil cylinder.

Preferably, the material of the electrode sheet is copper.

The present invention also provides a method for measuring core resistivity implemented by applying the above-mentioned core resistivity measuring device, which is characterized by comprising the following steps:

Step 1. Sampling for backup: select a cylindrical core and grind it. After grinding, soak the core in an electrolyte solution, and measure the length and diameter of the core after soaking;

Step 2: Install the test piece: first connect the electrode sheet to the measuring instrument; then soak two sponge pads in the electrolyte solution, place them on the two electrode sheets respectively, place the core in the groove of the lower base, and adjust the rotation. Tighten the bolts so that the top of the core is compressed by the upper base;

得到不同轴压条件下的岩心的电阻率值；其中，L为岩心长度，r为岩心半径，I为流经岩心的电流值，ΔU为两所述电极片之间的电位差。Step 3: Load the axial pressure and start the measurement: change the pressure exerted by the pressure loading device on the core, read the current value flowing through the core displayed on the measuring instrument and the potential difference between the two electrode sheets, and calculate the formula according to the resistivity.

Obtain the resistivity value of the core under different axial pressure conditions; wherein, L is the core length, r is the core radius, I is the current value flowing through the core, and ΔU is the potential difference between the two electrode sheets.

Preferably, the core is soaked in the electrolyte solution for at least 48 hours.

Preferably, the length L of the core is not greater than 300mm, and the radius r is not greater than 50mm.

Preferably, the electrolyte solution is a saturated copper sulfate solution.

The present invention has achieved the following technical effects with respect to the prior art:

1. In the present invention, the sponge gasket soaked with the electrolyte solution can ensure good contact between the electrode sheet and the core, and prevent the large contact resistance between the electrode sheet and the core from affecting the experimental results; During installation, the sponge gasket can play a buffering role to prevent the pressure sensor from being damaged by the impact during installation;

2. In the present invention, the pressure sensor, the electrode sheet and the sponge gasket are stacked. On the one hand, the occupied volume is smaller, which makes the structure more compact. On the other hand, the force can be directly transmitted to the core, and the measurement is more accurate; The upper base and the lower base are provided with grooves to fix the core, the fixing structure is simpler, and the installation process is more convenient;

3. In the present invention, the upper base and the movable end of the pressure loading device are connected by connecting bolts, which can more conveniently replace the upper base with different groove sizes, so as to measure the resistivity of more sizes of cores.

Description of drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings required in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some of the present invention. In the embodiments, for those of ordinary skill in the art, other drawings can also be obtained according to these drawings without creative labor.

Fig. 1 is the overall structure schematic diagram of the present invention;

Fig. 2 is a partial enlarged view of Fig. 1;

Among them, 1. Fixed frame; 2. Pressure loading device; 3. Core; 4. Upper base; 5. Lower base; 6. Adjustable movable part; 7. Groove; 8. Pressure sensor; 9. Electrode sheet; 10 , sponge gasket; 11, oil inlet; 12, piston.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

The purpose of the present invention is to provide a core resistivity measuring device and a measuring method thereof, so as to solve the problems existing in the above-mentioned prior art, and can accurately measure the resistivity of the core under different axial pressures, and has a simpler structure and more convenient operation. convenient.

In order to make the above objects, features and advantages of the present invention more clearly understood, the present invention will be described in further detail below with reference to the accompanying drawings and specific embodiments.

Example 1:

As shown in FIGS. 1 to 2 , this embodiment provides a resistivity measuring device for core 3 , including a measuring instrument, a fixed frame 1 , a pressure loading device 2 fixed on the fixed frame 1 , and an upper plate for holding the core 3 . The base 4, the lower base 5, the upper base 4 is fixed on the movable end of the pressure loading device 2, the lower base 5 is fixed at the end of an adjustable movable part 6, and the upper base 4 and the lower base 5 are provided with a fixed core 3 The groove 7 at the end, the two grooves 7 are arranged coaxially;

Between the end of the core 3 and the bottom surface of the groove 7, a pressure sensor 8, an electrode sheet 9 and a sponge gasket 10 soaked with an electrolyte solution are also stacked in sequence. The sponge gasket 10 is in contact with the end of the core 3, and the pressure sensor 8 and the The electrode pieces 9 are all electrically connected to the measuring instrument; the specific positions and electrical connection methods of the wire outlet holes are well known to those skilled in the art, and therefore are not described in detail in this embodiment.

During the test, the core 3 is clamped between the upper base 4 and the lower base 5, and by changing the loading pressure of the pressure loading device 2, the measuring instrument can measure the potential difference and the According to the current value flowing through the core 3, the conductivity of the core 3 under different axial pressure can be measured according to the formula.

In this embodiment, the pressure sensor 8 and the electrode sheet 9 are used to transmit the measured pressure data and current potential data to the measuring instrument. The sponge gasket 10 soaked with the electrolyte solution has strong conductivity, which can ensure the electrode sheet 9 Good contact with the core 3 prevents the large contact resistance between the electrode sheet 9 and the core 3 from affecting the experimental results.

In this embodiment, by setting the sponge gasket 10, during installation, the sponge gasket 10 can play a buffering role due to its strong elastic deformation ability, preventing the pressure sensor 8 from being damaged by the impact during installation; and the pressure sensor 8, the electrode The sheet 9 and the sponge gasket 10 are stacked, on the one hand, the occupied volume is smaller, which makes the structure more compact, and on the other hand, the force can be directly transmitted to the core 3, and the measurement is more accurate.

In this embodiment, the upper base 4 and the lower base 5 are provided with grooves 7 to fix the core 3, the fixing structure is simpler, and the installation process is also more convenient.

Further, the upper base 4 and the movable end of the pressure loading device 2 are connected by connecting bolts, so that the upper base 4 with different grooves 7 can be replaced more conveniently, so that the resistivity of the cores 3 of more sizes can be adjusted. Measurement; and the upper base 4 is coaxially arranged with the movable end of the pressure loading device 2, so that the force is evenly and axially applied to the upper base 4 to ensure the accuracy of the measurement.

In this embodiment, the adjustable movable portion 6 is a tightening bolt.

In this embodiment, the pressure loading device 2 is a telescopic oil cylinder, and the telescopic oil cylinder has an oil inlet hole 11 , and the piston 12 is connected to the base 4 by connecting bolts. The telescopic cylinder expands and contracts smoothly and can precisely control the pressure.

In this embodiment, the material of the electrode sheet 9 is copper, and the thickness is 3 mm˜5 mm; of course, other electrode sheets 9 with excellent conductivity are also feasible.

Example 2:

The present embodiment provides a method for measuring core resistivity implemented by applying the above-mentioned core resistivity measuring device, which is characterized in that it includes the following steps:

Step 1. Sampling for backup: select the cylindrical core 3 and grind it. After the grinding, soak the core 3 in the electrolyte solution, and measure the length and diameter of the core 3 after soaking;

Step 2, install the test piece: first connect the electrode sheet 9 with the measuring instrument; then two sponge pads 10 are soaked in the electrolyte solution, respectively installed on the two electrode sheets 9, and the core 3 is placed in the groove of the lower base 5 In 7, adjust the tightening bolt so that the top of the core 3 is pressed by the upper base 4;

得到不同轴压条件下的岩心3的电阻率值；其中，L为岩心3长度，r为岩心3半径，I为流经岩心3的电流值，ΔU为两电极片9之间的电位差。Step 3: Load the axial pressure and start the measurement: change the pressure applied by the pressure loading device 2 to the core 3, read the current value that flows through the core 3 displayed on the measuring instrument and the potential difference between the two electrode sheets 9, according to the resistivity Calculation formula

Obtain the resistivity value of the core 3 under different axial pressure conditions; wherein, L is the length of the core 3, r is the radius of the core 3, I is the current value flowing through the core 3, and ΔU is the potential difference between the two electrode sheets 9 .

Since most of the rocks in the crust are in the groundwater environment, it is necessary to fully soak the core in water before the measurement to simulate the actual water content. 48h.

Further, in order to ensure that the core 3 can be completely penetrated within a specified time and ensure the accuracy and convenience of measurement, in this embodiment, the length L of the core 3 is not greater than 300mm, and the radius r is not greater than 50mm.

Further, the electrolyte solution is a saturated copper sulfate solution, of course, other saturated electrolyte solutions can also be used.

Adaptive changes made according to actual needs are all within the protection scope of the present invention.

In the present invention, specific examples are used to illustrate the principles and implementations of the present invention, and the descriptions of the above embodiments are only used to help understand the method and the core idea of the present invention; There will be changes in the specific implementation manner and application scope of the idea of the invention. In conclusion, the contents of this specification should not be construed as limiting the present invention.

Claims (9)

1. A rock core resistivity measuring device is characterized by comprising a measuring instrument, a fixed frame, a pressure loading device fixed on the fixed frame, an upper base and a lower base, wherein the upper base is used for clamping a rock core; grooves for fixing the end parts of the rock cores are formed in the upper base and the lower base, and the two grooves are coaxially arranged;

the measuring instrument is characterized in that a pressure sensor, an electrode plate and a sponge gasket soaked by electrolyte solution are sequentially stacked between the end part of the core and the bottom surface of the groove, the sponge gasket is in contact with the end part of the core, and the pressure sensor and the electrode plate are electrically connected with the measuring instrument.

2. The core resistivity measuring device as claimed in claim 1, wherein the upper base is connected with the movable end of the pressure loading device by a connecting bolt, and the upper base is coaxially arranged with the movable end of the pressure loading device.

3. The core resistivity measuring device as claimed in claim 1, wherein the adjustable movable portion is a tightening bolt which is fixed on the fixed frame in a threaded manner.

4. The core resistivity measurement device according to claim 1, wherein the pressure loading device is a telescopic cylinder.

5. The core resistivity measuring device as claimed in claim 1, wherein the electrode sheet is made of copper.

6. A core resistivity measurement method implemented by using the core resistivity measurement device according to any one of claims 1 to 5, is characterized by comprising the following steps:

step one, sampling for standby: selecting a cylindrical core, polishing, soaking the core in an electrolyte solution after polishing, and measuring the length and the diameter of the core after soaking;

step two, mounting a test piece: firstly, connecting the electrode plate with a measuring instrument; then soaking two sponge gaskets in an electrolyte solution, respectively arranging the two sponge gaskets on the two electrode sheets, placing the rock core in a groove of the lower base, and adjusting a screwing bolt to enable the top end of the rock core to be tightly pressed by the upper base;

loading axial pressure and starting measurement: changing the pressure applied to the rock core by the pressure loading device, reading the current value flowing through the rock core and the potential difference between the two electrode plates displayed on the measuring instrument, and calculating the formula according to the resistivity

Obtaining the resistivity values of the rock cores under different axial pressure conditions; wherein L is the core length, r is the core radius, I is the current value flowing through the core, and Delta U is the potential difference between the two electrode plates.

7. The method for measuring core resistivity as claimed in claim 6, wherein the core is soaked in the electrolyte solution for at least 48 hours.

8. The method as recited in claim 6, wherein the core has a length L of no greater than 300mm and a radius r of no greater than 50 mm.

9. The method as recited in claim 6, wherein the electrolyte solution is a saturated copper sulfate solution.

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