Disclosure of Invention
The invention aims to provide a test method for simulating the downloading of marine bidirectional electromagnetic measurement-while-drilling signals, which can effectively explore the influence factors of the downloading of the bidirectional electromagnetic measurement-while-drilling signals in marine drilling.
The invention provides a test device for simulating marine bidirectional electromagnetic measurement-while-drilling signal downloading, which comprises: the device comprises a box body, a sleeve, a transmitting electrode, an upper drill rod, an insulating short section, a lower drill rod, a signal generator and a signal receiver;
the box body is used for placing a simulated ocean, and the simulated ocean comprises a simulated lower stratum, a simulated reservoir stratum, a simulated upper stratum, a simulated seabed soil layer and a simulated seawater layer which are paved from bottom to top in sequence;
one end of the insulating short section is connected with the lower drill rod; the insulation short joint and the lower drill pipe are used for being arranged in the simulated reservoir;
one end of the sleeve is inserted into the simulated upper stratum, and the other end of the sleeve extends above the simulated seawater layer;
the upper drill rod is used for being inserted into the sleeve, and the lower end of the upper drill rod is connected with the insulating short section;
the transmitting electrode is arranged on the simulated seawater layer in a suspending manner or inserted on the simulated seabed soil layer;
the positive electrode and the negative electrode of the signal generator are respectively and electrically connected with the upper end of the upper drill rod and the transmitting electrode;
and the positive electrode and the negative electrode of the signal receiver are respectively and electrically connected with the lower end of the upper drill rod and the lower drill rod.
Furthermore, the box body is of a top opening structure and is transparent.
Furthermore, the box body is made of transparent organic glass.
Further, the upper drill rod and the lower drill rod are respectively connected with the insulation short section through hot melt adhesives.
Furthermore, the upper drill rod and the lower drill rod are made of stainless steel respectively.
Furthermore, the sleeve is made of stainless steel.
Furthermore, the insulating short section is made of plastic.
The invention also provides a test method for simulating the marine bidirectional electromagnetic measurement-while-drilling signal downloading according to the test device for simulating the marine bidirectional electromagnetic measurement-while-drilling signal downloading, which comprises the following steps:
s101, laying a simulation lower stratum, a simulation reservoir stratum, a simulation upper stratum, a simulation seabed soil layer and a simulation seawater layer in the box body from bottom to top in sequence; when the simulated reservoir stratum is paved, the upper drill rod, the insulating short section and the lower drill rod are sequentially connected, the insulating short section and the lower drill rod are arranged in the simulated reservoir stratum, and then the lower end of the upper drill rod and the lower drill rod are respectively and electrically connected with the positive electrode and the negative electrode of the signal receiver;
s102, sleeving the sleeve outside the upper drill rod, inserting the lower end of the sleeve into the simulated upper stratum, extending the other end of the sleeve above the simulated seawater layer, floating the transmitting electrode on the simulated seawater layer or inserting the transmitting electrode on the simulated seabed stratum through a floating body, and electrically connecting the upper end of the upper drill rod and the transmitting electrode with the positive electrode and the negative electrode of the signal generator respectively;
s103, the signal generator and the signal receiver are connected with a power supply, and the bidirectional electromagnetic measurement while drilling signal downloading test in the marine drilling under different test conditions is simulated by a control variable method, so that influence factors of the bidirectional electromagnetic measurement while drilling signal downloading in the marine drilling are obtained.
Further, in step S103, the test conditions include resistivity of the simulated seawater layer, a length of the transmitting electrode, a transmitting voltage of the signal generator, a distance between the transmitting electrode and the upper drill pipe, and an orientation of the transmitting electrode relative to the upper drill pipe.
Further, the floating body comprises a foam floating ball or a plastic floating ball.
The technical scheme provided by the embodiment of the invention has the following beneficial effects: the test device for simulating the marine bidirectional electromagnetic measurement-while-drilling signal downloading in the embodiment of the invention comprises a box body, a sleeve, a transmitting electrode, an upper drill rod, an insulating short section, a lower drill rod, a signal generator and a signal receiver; when the device is used, a simulation lower stratum, a simulation reservoir stratum, a simulation upper stratum, a simulation seabed soil layer and a simulation seawater layer are sequentially paved in the box body from bottom to top; when the simulated reservoir stratum is paved, the upper drill rod, the insulating short section and the lower drill rod are sequentially connected, the insulating short section and the lower drill rod are arranged in the simulated reservoir stratum, and then the lower end of the upper drill rod and the lower drill rod are respectively and electrically connected with the positive electrode and the negative electrode of the signal receiver; sleeving the sleeve outside the upper drill rod, inserting the lower end of the sleeve into the simulated upper stratum, extending the other end of the sleeve above the simulated seawater layer, floating the transmitting electrode on the simulated seawater layer or inserting the transmitting electrode on the simulated seabed soil layer through a floating body, and electrically connecting the upper end of the upper drill rod and the transmitting electrode with the positive electrode and the negative electrode of the signal generator respectively; and finally, the signal generator and the signal receiver are connected with a power supply, and the bidirectional electromagnetic measurement-while-drilling signal downloading test in the marine drilling under different test conditions is simulated by controlling a variable method, so that the influence factors of the bidirectional electromagnetic measurement-while-drilling signal downloading in the marine drilling are obtained, the test device is simple, the disassembly and the maintenance are convenient, and the test cost is saved.
Detailed Description
The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate preferred embodiments of the invention and together with the description, serve to explain the principles of the invention and not to limit the scope of the invention.
Referring to fig. 1, an embodiment of the present invention provides a test apparatus for simulating marine bidirectional electromagnetic measurement while drilling signal downloading, including: the device comprises a box body 9, a sleeve 4, a transmitting electrode 5, an upper drill rod 6, an insulating short section 7, a lower drill rod 8, a signal generator 1 and a signal receiver 2;
the box body 9 is used for placing a simulated ocean, and the simulated ocean comprises a simulated lower stratum 14, a simulated reservoir 13, a simulated upper stratum 12, a simulated seabed soil layer 11 and a simulated seawater layer 10 which are laid in sequence from bottom to top; the box body 9 is of a top opening structure; in order to observe the internal condition of the box body 9 conveniently, the side wall of the box body 9 is transparent, so that the thickness of the simulated ground layer can be controlled conveniently; the bottom of the box body 9 adopts a reinforced steel plate to meet the bearing requirement;
one end of the insulating short section 7 is connected with a lower drill rod 8; the insulating short joint 7 and the lower drill rod 8 are arranged in the simulated reservoir 13; the lower drill rod 8 is connected with the insulating short section 7 through hot melt adhesive; the lower drill rod 8 is made of stainless steel; the insulating short section 7 is made of plastic;
one end of the casing 4 is inserted into the simulated upper stratum 12, and the other end of the casing is extended above the simulated seawater layer 10; the sleeve 4 is made of stainless steel;
the upper drill rod 6 is used for being inserted into the casing 4, and the lower end of the upper drill rod 6 is connected with the short insulating section 7; the upper drill rod 6 is connected with the insulating short section 7 through hot melt adhesive; the upper drill rod 6 is made of stainless steel;
the transmitting electrode 5 is arranged on the simulated seawater layer 10 in a suspending manner or is inserted on the simulated seabed soil layer 11;
the anode and the cathode of the signal generator 1 are respectively and electrically connected with the upper end of the upper drill rod 6 and the transmitting electrode 5 through leads 3;
the anode and the cathode of the signal receiver 2 are respectively and electrically connected with the lower end of the upper drill rod 6 and the lower drill rod 8 through the lead 3.
When in use, the signal generator 1 and the signal receiver 2 are connected with a power supply, and the test conditions are changed to carry out simulation tests; specifically, the control instruction uses low-frequency electromagnetic waves as carriers, signal emission is carried out by a signal generator 1, and a signal receiver 2 acquires and processes signals to obtain a downloaded control instruction; by adopting a control variable method, the influence of different factors on the signal downloading effect is researched.
The signal generator 1 transmits the electromagnetic signal to the bottom of the well in a sine wave form, and the signal receiver 2 filters the sine wave received by the bottom of the well to obtain the signal intensity of the potential difference.
It should be noted that the meanings of the letters in fig. 1 and 2 are as follows: h is the well depth, i.e. the vertical distance between the top of the casing 4 and the lower drill rod 8; d is the distance between the emitter electrode 5 and the upper drill rod 6; l, the length of the horizontal sections of the lower end of the upper drill rod 6, the insulating short section 7 and the lower drill rod 8 is increased; h1 is the depth of the simulated seawater layer 10; h2 is the thickness of the simulated seabed layer 11; h3 is the thickness of the simulated upper formation 12; h4 is the thickness of the reservoir; h5 is the thickness of the lower sub-layer.
Exemplarily, in the present embodiment, the material of the box 9 is transparent organic glass; the gap sub 7 and the lower drill pipe 8 are vertically arranged in a simulated reservoir 13, namely a vertical well.
Referring to fig. 2, as a variation of this embodiment, the gap sub 7 and the lower drill pipe 8 may also be horizontally disposed in the simulated reservoir 13, i.e., a horizontal well.
Referring to fig. 3, the test method for simulating the marine bidirectional electromagnetic measurement while drilling signal downloading by using the test apparatus for simulating the marine bidirectional electromagnetic measurement while drilling signal downloading in the embodiment includes the following steps:
s101, laying a simulation lower stratum 14, a simulation reservoir stratum 13, a simulation upper stratum 12, a simulation seabed soil layer 11 and a simulation seawater layer 10 in the box body 9 from bottom to top in sequence; when a simulated reservoir stratum 13 is paved, an upper drill rod 6, an insulating short section 7 and a lower drill rod 8 are sequentially connected, the insulating short section 7 and the lower drill rod 8 are arranged in the simulated reservoir stratum 13, and then the lower end of the upper drill rod 6 and the lower drill rod 8 are respectively and electrically connected with the positive electrode and the negative electrode of a signal receiver 2 through leads 3;
s102, sleeving the sleeve 4 on the outer side of the upper drill rod 6, inserting the lower end of the sleeve 4 on the simulated upper stratum 12, extending the other end edge of the sleeve 4 to be above the simulated seawater layer 10, floating the transmitting electrode 5 on the simulated seawater layer 10 or inserting the transmitting electrode 5 on the simulated seabed soil layer 11 through the floating body 15, and then electrically connecting the upper end of the upper drill rod 6 and the transmitting electrode 5 with the positive and negative electrodes of the signal generator 1 through the wires 3 respectively;
s103, the signal generator 1 and the signal receiver 2 are connected with a power supply, and the bidirectional electromagnetic measurement while drilling signal downloading test in the marine drilling under different test conditions is simulated by a control variable method, so that influence factors of the bidirectional electromagnetic measurement while drilling signal downloading in the marine drilling are obtained.
In this embodiment, the floating body 15 may be a floating foam ball or a floating plastic ball, for example.
Specifically, in step S103, the test conditions include the resistivity of the simulated seawater layer 10, the length of the emitter electrode 5, the emitter voltage of the signal generator 1, the distance between the emitter electrode 5 and the upper drill pipe 6, and the orientation of the emitter electrode 5 with respect to the upper drill pipe 6.
(1) The more the content of the electrolyte in the simulated seawater layer 10 is, the better the conductivity is, the smaller the resistivity is, and the seawater with different resistivity is simulated by changing the salt dissolution amount in the brine; the simulated seawater resistivity under different salt dissolution amounts is measured by using the resistivity measuring device, and under the condition that all other variables are not changed, the influence rule of the seawater resistivity on the bidirectional electromagnetic measurement while drilling signal downloading in the marine drilling can be judged according to the data obtained by the signal receiver 2 under different seawater resistivities.
(2) Changing the length of the emitter electrode 5; keeping the other variables unchanged, setting the lengths of different transmitting electrodes 5, and determining that the transmitting electrodes float on the water surface or are inserted into a simulated seabed soil layer 11 by utilizing a foam floating ball according to the lengths of the transmitting electrodes 5; and obtaining the influence rule of the length of the transmitting electrode 5 on the downlink of the bidirectional electromagnetic measurement-while-drilling signal in the marine drilling from the data obtained by the signal receiver 2 under different electrode lengths.
(3) Changing the transmission voltage of the signal generator 1; the transmitted voltage of the signal directly determines the frequency of the transmitted signal, the transmitted voltage is used as a variable, and the data obtained by the signal receiver 2 can directly reflect the influence rule of the transmitted voltage on the downlink of the bidirectional electromagnetic measurement-while-drilling signal in the marine drilling on the basis of unchanged other conditions.
(4) The distance between the transmitting electrode 5 and the upper drill rod 6 is used as a variable, other conditions are kept unchanged, the distance between the transmitting electrode 5 and the upper drill rod 6 is changed in sequence, and the influence rule of the distance between the transmitting electrode 5 and the upper drill rod 6 on the downlink of the bidirectional electromagnetic measurement-while-drilling signal in the marine drilling can be obtained according to the data received by the signal receiver 2.
(5) The position of the transmitting electrode 5 relative to the upper drill rod 6 is used as a variable, and under the condition of ensuring that other conditions are completely consistent, the receiving voltage of the signal receiver 2 corresponding to the transmitting position is measured and recorded every time the transmitting position is changed, so that the influence rule of the transmitting position on the downlink of the bidirectional electromagnetic measurement-while-drilling signal in the marine drilling is obtained.
Illustratively, referring to fig. 1, the influence of the distance d between the transmitting electrode 5 and the upper drill pipe 6 on the down-transmission efficiency of the downhole bidirectional electromagnetic measurement-while-drilling signal is studied, and the operation steps are as follows:
(1) a simulation lower part is laid in the box body 9 from bottom to top in sequenceA stratum 14, a simulated reservoir 13, a simulated upper stratum 12, a simulated seabed soil layer 11 and a simulated seawater layer 10, and connecting instruments; wherein the depth of the box body 9 is 1.5m, the depth h of the vertical well section is 1.2m, the length L of the horizontal section is 30cm (in the embodiment, the horizontal section is vertically arranged; the horizontal section is described here only for expressing the length of the corresponding section in the vertical well and the horizontal well), the depth h1 of the simulated seawater layer 10 is 15cm, the thickness h2 of the simulated seabed soil layer 11 is 10cm, the thickness h3 of the simulated upper stratum 12 is 40cm, the thickness h4 of the simulated reservoir layer 13 is 40cm, and the thickness h5 of the simulated lower stratum 14 is 15 cm; the resistivity of the simulated sea water layer 10 was measured to be 5.4 Ω · m for σ 1, 31.27 Ω · m for σ 2, 56.67 Ω · m for σ 3, 826.67 Ω · m for σ 4, 54.72 Ω · m for σ 5, and 7.3 × 10 for σ for the upper drill pipe 6 and the lower drill pipe 8 by the resistivity measuring device-7Omega.m, the length of the lower drill rod 8 is 5cm, the diameter of the short insulating joint 7 is 1.5cm, the length is 5cm, the resistivity sigma 7 is 1.02 multiplied by 105Omega.m, the outer diameter of the sleeve 4 is 2.5cm, the wall thickness is 0.2cm, the length is 60cm, the transmitting voltage of the signal is 5V, the diameter of the transmitting electrode 5 is 2mm, and the length is 50 cm;
(2) under the condition that other test conditions are kept unchanged, the distances d between the transmitting electrode 5 and the upper drill rod 6 are sequentially set to be 5cm, 10cm, 15cm, 20cm and 25cm, and potential difference signal intensity data received by the signal receiver 2 at different distances are obtained;
(3) according to the potential difference signal intensity data received by the signal receiver 2 under the condition of the distances d between different transmitting electrodes 5 and the simulated drill rods, the influence rule of the distance between the transmitting electrode 5 and the upper drill rod 6 on the signal downloading efficiency of the vertical well bidirectional electromagnetic measurement while drilling can be researched.
Illustratively, referring to fig. 2, the influence of the emission voltage on the download efficiency of the bidirectional electromagnetic measurement-while-drilling signal of the horizontal well is studied, and the operation steps are as follows:
(1) a simulation lower stratum 14, a simulation reservoir stratum 13, a simulation upper stratum 12, a simulation seabed soil layer 11 and a simulation seawater layer 10 are sequentially laid in the box body 9 from bottom to top and connected with instruments; wherein, the box bodyThe depth of 9 is 1.5m, the depth h of a vertical well section is 1.2m, the length L of a horizontal section is 30cm, the depth h1 of a simulated seawater layer 10 is 15cm, the thickness h2 of a simulated seabed soil layer 11 is 10cm, the thickness h3 of a simulated upper stratum 12 is 40cm, the thickness h4 of a simulated reservoir layer 13 is 40cm, and the thickness h5 of a simulated lower stratum 14 is 15 cm; the resistivity of the simulated sea water layer 10 was measured to be 5.4 Ω · m for σ 1, 31.27 Ω · m for σ 2 of the simulated seabed 11, 56.67 Ω · m for σ 3 of the simulated upper formation 12, 826.67 Ω · m for σ 4 of the simulated reservoir 13, 54.72 Ω · m for σ 5 of the lower formation, and 7.3 × 10 for σ of the upper drill pipe 6 and the lower drill pipe 8 by the resistivity measuring device-7Omega.m, the length of the lower drill rod 8 is 5cm, the diameter of the gap sub 7 is 1.5cm, the length is 5cm, the resistivity sigma 7 is 1.02 multiplied by 105Omega.m, the outer diameter of the sleeve 4 is 2.5cm, the wall thickness is 0.2cm, the length is 60cm, the transmitting voltage of the signal is 5V, the diameter of the transmitting electrode 5 is 2mm, the length is 35cm, and the sleeve floats in seawater by utilizing a foam floating ball;
(2) under the condition that other test conditions are kept unchanged, the emission voltages of the signals are sequentially set to be 5cm, 10cm, 15cm, 20cm and 25cm, and potential difference signal intensity data received by the signal receiver 2 under different emission voltages are obtained;
(3) according to the potential difference data obtained by the signal receiver 2 under different transmitting voltages, the influence rule of the transmitting voltages on the signal downloading efficiency of the horizontal well bidirectional electromagnetic measurement while drilling can be explored.
By analogy, the influences of the resistivity of the simulated seawater layer 10, the length of the transmitting electrode 5, the transmitting voltage of the signal generator 1, the distance between the transmitting electrode 5 and the upper drill rod 6 and the orientation of the transmitting electrode 5 relative to the upper drill rod 6 on the bidirectional electromagnetic measurement-while-drilling signal downloading efficiency can be sequentially and respectively researched.
The test device for simulating the marine bidirectional electromagnetic measurement while drilling signal downloading in the embodiment has the following advantages:
1. the device can simulate the bidirectional measurement while drilling signal downloading field test in the marine drilling which is difficult to realize, meets most test requirements, and saves the huge cost of the field test;
2. the embodiment is visual and flexible, the test result is reliable, the device is simple, and the disassembly, assembly and maintenance are convenient;
3. the transparent organic glass box body 9 is adopted in the embodiment, so that the physical properties of the in-groove device can be monitored conveniently;
4. in the embodiment, different sandy soils can be adopted to change the resistivity of the simulated formation, and the resistivity of the simulated seawater layer 10 can also be changed by changing the salt dissolution amount;
5. in the embodiment, the connection positions of the signal receiver 2 and the signal generator 1 can be exchanged according to requirements, and two tests of uploading and downloading of bidirectional electromagnetic measurement while drilling in marine drilling can be simultaneously carried out.
The above is not relevant and is applicable to the prior art.
In this document, the terms front, back, upper and lower are used to define the components in the drawings and the positions of the components relative to each other, and are used for clarity and convenience of the technical solution. It is to be understood that the use of the directional terms should not be taken to limit the scope of the claims.
The features of the embodiments and embodiments described herein above may be combined with each other without conflict.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.