RU2604561C1 - Insulator for acoustic logging instrument during drilling - Google Patents

Abstract

FIELD: geophysics.

SUBSTANCE: invention relates to geophysics and can be used during acoustic logging in drilling oil and gas wells. Disclosed is an insulator for an acoustic logging instrument during drilling, which contains a bearing pipe from fiberglass with steel ends arranged between units of the radiator and the receiving antenna. In the cavity of the bearing pipe there is a protective casing with formation of an annular channel for the drilling fluid, and inside the protective casing there are transit wires. Ends of the casing are provided with extending parts for fixing in steel endings of the bearing pipe and comprise electrical connectors. Steel ends are made with conical metric or locking threads. Protective casing is made from fiberglass with steel ends, in which there is a thin-wall plastic tube for the transit wires made with an acoustic isolation from the protective casing, in the annular cavity of which there is an absorber of elastic vibrations. Absorber of elastic vibrations is made by filling with a silicone rubber and a heavy metal powder or consists of alternating metal washers and washers from a silicon rubber with a powder of heavy metals and metal balls or rollers. Silicone rubber washers with the powder of heavy metals are implemented of the quarter-wave length for the main frequency of monopole radiation, and the electric connectors are made of rotary or wireless type.

EFFECT: improved strength properties of the acoustic insulator and essential filtration of elastic vibrations of the housing.

11 cl, 2 dwg

Description

The invention relates to acoustic logging equipment in the process of drilling oil and gas wells as part of the layout of the bottom of the drill string.

A feature of downhole tools in the drilling process are the requirements of strength, rigidity and hydraulics. Power loads exceed almost by an order of magnitude the loads typical for instruments on a geophysical cable (several tons) and stand-alone devices (units of tens of tons), and drilling fluid costs are tens of l / s. Therefore, supporting instrument housings, as a rule, are thick-walled steel structures with an outer diameter close to the diameter of the wellbore, and also have a channel for the drilling fluid. When using such structures in acoustic logging tools during drilling, a serious problem is the high-quality isolation from the wave along the body of the device, which occurs when emitters are triggered and propagates towards the receiving antenna. With comparable first entry times, amplitude and frequency content, the wave along the body can interfere with useful signals, making processing impossible to determine the elastic wave velocities in the rock. The main role in the delay and attenuation of the wave along the body is played by an acoustic insulator located in the gap between the emitters and receivers. Most of the known technical solutions are based on the principle of introducing various inhomogeneities into the body of the bearing steel drill pipe, which are made with a wave impedance different from the wave impedance of steel, due to which part of the wave energy through the body is lost when passing through the insulator.

Known acoustic attenuator of a device for geophysical research of underground formations (see US patent No. 5510582, IPC G01V 01/52, publication of 04/23/1996), made in the form of a section with cavities in a bearing steel pipe filled with silicone fluid, in which inertial elements are placed masses made of high density metals, the inertial massive elements including a finger and a cap lock, an o-ring and a bolt.

The disadvantage of the technical solution is that the inhomogeneities in the carrier pipe are a small part, so a significant part of the wave energy in the body can reach the receiving antenna. In addition, wire transit is not provided without an additional device that can only be installed in the mud channel.

Known acoustic wave attenuator for the housing used for the measuring device during drilling (see US patent No. 6082484, IPC G01V 01/52, publication of 07/04/2000), containing sections of acoustic attenuation of the wave along the body based on a weighted drill pipe filled with layers a composite material in which the layers have different densities, and the layer thickness is selected to attenuate certain signal frequencies, another option is a drill pipe section with spherical cavities in the pipe body staggered for increasing the path length of the propagating acoustic signal, or cylindrical cavities with pistons held by a spring within the cavity, and the cavity is filled with liquid.

The advantage of this solution is the use of material from composite layers in the cavity of the insulator, which allows you to weaken and delay the wave along the body, and the steel pipe can withstand the load during drilling.

The main disadvantages of the technical solution is that the main part of the drill pipe is preserved and remains a waveguide, contributing to the passage of elastic vibrations, and there is no possibility of wire transit without an additional device.

A known acoustic insulator for use in equipment for acoustic research during drilling in an underground rock mass (see US patent No. 7028806, IPC G01V 01/40, publication of 04/18/2006) containing a drill pipe with a logging device having composed of an insulator with the possibility of attenuation of acoustic signals within a predetermined frequency range, placed between acoustic emitters and receivers and including a tubular element of composite material having basically a cylinder outer surface with a group of bodies of a certain mass and length rigidly fixed on it and located with a given gap, and the bodies contain a material selected from the group consisting of steel and tungsten rings or from a material whose density is not less than the density of the tubular element, and the logging device and the drill pipe have longitudinally elongated channels with drilling fluid flowing through them. The bodies can be fixed both to the inner wall of the drill pipe and to the outside, for example, by welding.

The disadvantages of this invention are:

- for the option of external fixing of bodies on the drill pipe, the surface and all cavities can become clogged with sludge, which impairs acoustic insulation and complicates maintenance after drilling;

- the option of securing the bodies to the inner surface of the drill pipe is complicated from the point of view of manufacture;

- for the option of attaching to the inner pipe, the effectiveness of the insulator decreases sharply due to the lack of contact with the drill pipe, which is the main waveguide for interference;

- for all versions there is no possibility of wire transit without an additional device.

The technical result of the proposed solution is the creation of an acoustic insulator, which would combine sufficient strength properties with the parameters of wave delay along the body and attenuation of its amplitude, as well as the ability to electrical connection without additional devices and was convenient in maintenance.

The technical result of the proposed solution is achieved by the fact that the insulator of the acoustic logging tool during drilling contains a carrier pipe located in the gap between the emitter and receiver antenna units, in addition, the carrier pipe is made of fiberglass with steel ends, and a protective casing with the formation of an annular channel for the drilling fluid, and inside the protective casing transit wires are placed, in addition, the ends of the casing are implemented with protruding parts for fixing tion in a steel carrier pipe terminations and electrical connectors include.

Steel ends of the supporting pipe are made with metric or lock threads (GOST R 50864-96).

The protective casing is made of fiberglass with steel ends, in which a thin-walled tube for transit wires is placed, made of plastic and realized with acoustic isolation from the protective casing, in the annular cavity of which an absorber of elastic vibrations is introduced.

The elastic vibration absorber is made of silicone rubber with a powder of heavy metal or is composed of alternating metal washers and washers of silicone rubber with a powder of heavy metals and metal balls or rollers.

Silicone rubber washers with heavy metal powder are implemented in a quarter-wave length for the main frequency of monopole radiation, and the electrical connectors are made of rotary or wireless type.

The essence of the technical solution is that the fiberglass support pipe provides wave filtering over the body in the range of 8.5-13 kHz with an attenuation of the amplitude of at least 40 dB only due to the elastic properties of the material according to computer simulation, and in real conditions due to anisotropy and structural heterogeneity attenuation may be even higher. In addition, due to the lower elastic modulus and, accordingly, the propagation velocity compared to steel, the necessary delay of the first arrival of the interference wave is provided, which allows the waves to be separated in the wave packet for further processing. In addition, fiberglass made using the technology of slanting longitudinal-transverse winding developed by ZAO Altik (Biysk RU) is recommended for the manufacture of tool bodies during drilling, in particular electromagnetic logging tools, meeting the requirements of strength and wear resistance. So, a pipe with an outer diameter of 120 mm and a wall thickness of 20 mm at a temperature of 100 ° C can withstand a torsion moment of more than 10 kNm and a tensile force of at least 1000 kN.

The introduction of a protective casing for transit wires solves the problem of the electrical connection of the emitter blocks and the receiving antenna. The guard is sealed and designed to work under pressure from the external environment. Since the casing is also a waveguide for the wave along the casing, it is made of fiberglass with steel ends, it contains a thin-walled plastic tube with wires, and an absorber of elastic vibrations is introduced into the annular cavity, which draws the energy of the interference wave from the casing.

To connect to the emitter and receiving antenna units, rotary electrical connectors (for example, SPT (SE), or wireless type connectors (for example, a transformer coupling device) are used, which facilitate the assembly-disassembly of the device.

Moreover, the washers, an absorber of elastic vibrations, are made of silicone rubber of low viscosity, for example RTV8001, with a powder of heavy metal, for example tungsten, including metal balls or rollers.

Comparison of the proposed solution with the known technical solutions shows that it has a new set of essential features that, together with the known features, can successfully achieve the goal.

The proposed technical solution is illustrated by drawings, where in FIG. 1 - shows the spectrum of the output pulse at the insulator slice, showing a window in the range of 8.5-13 kHz with an amplitude attenuation of at least 40 dB only due to the elastic properties of the material, according to computer simulation in the Ansys / LS-Dyna software package (US), and in FIG. 2 - presents a General view of the acoustic insulator.

The composition of the proposed technical solution:

1. The bearing pipe;

2. Steel endings;

3. Security cover;

4. The channel for the drilling fluid;

5. The protruding part of the protective casing;

6. Stopper;

7. Thin-walled tube;

8. Electrical connector;

9. The latch;

10. Absorber;

11. Metal washers;

12. Rubber-like washers;

13. Balls or rollers.

The dynamics of the device

The insulator includes a fiberglass outer pipe 1 with steel ends 2, a guard 3 with the formation of an annular flushing channel 4, and the casing at the edges has protruding parts 5, with through holes for flushing fluid and by which it is fixed from rotation and longitudinal movement relative to the outer pipe with retaining rings 6, and in the casing 3 there is a thin-walled plastic tube 7 with acoustic isolation, in which transit wires are laid, connected along the edges with electrical connectors 8, fixed by clamps 9, in addition, in the annular cavity of the casing 3 there is an elastic vibration absorber 10 made of a rubber-like mixture based on silicone rubber with a powder of heavy metal, for example tungsten, or containing alternating metal washers 11 and washers 12 of the specified material, including with metal balls or rollers 13.

The technical and economic effect of the proposed solution is a significant attenuation of the wave along the body of the acoustic logging tool during drilling, providing an annular channel for the drilling fluid, providing electrical communication between the emitter and receiving antenna units, simplicity and reliability of the design, and ease of maintenance.

Claims (11)

1. The insulator of the acoustic logging tool during drilling, containing the carrier pipe located in the gap between the blocks of the emitter and the receiving antenna, characterized in that the carrier pipe is made of fiberglass with steel ends, and in the cavity of the carrier pipe is placed a protective casing with the formation of an annular channel for drilling fluid, and inside the protective casing transit wires are placed, in addition, the ends of the casing are implemented with protruding parts for fixing in the steel ends of the carrier pipe and include electrical connectors. 2. The insulator of the acoustic logging tool during drilling according to claim 1, characterized in that the steel ends of the carrier pipe are made with tapered metric or locking threads. 3. The insulator of the acoustic logging tool during drilling according to claim 1, characterized in that the guard is made of fiberglass with steel ends. 4. The insulator of the acoustic logging tool during drilling according to paragraphs. 1, 3, characterized in that the protective casing contains a thin-walled tube for transit wires. 5. The insulator of the acoustic logging tool during drilling according to claim 4, characterized in that the thin-walled tube is implemented with acoustic isolation from the guard. 6. The insulator of the acoustic logging tool during drilling according to claim 4, characterized in that the thin-walled tube is made of plastic. 7. The insulator of the acoustic logging tool while drilling according to paragraphs. 1, 3, characterized in that an absorber of elastic vibrations is introduced into the annular cavity of the guard. 8. The insulator of the acoustic logging tool during drilling according to claim 6, characterized in that the elastic vibration absorber is made of silicone rubber with a powder of heavy metal. 9. The insulator of the acoustic logging tool during drilling according to claim 6, characterized in that the absorber of elastic vibrations is composed of alternating metal washers and washers made of silicone rubber with heavy metal powder and metal balls or rollers. 10. The insulator of an acoustic logging tool during drilling according to claim 8, characterized in that the washers of silicone rubber with a powder of heavy metals are implemented in a quarter-wavelength length for the fundamental frequency of monopole radiation. 11. The insulator of the acoustic logging tool during drilling according to claim 1, characterized in that the electrical connectors are made of rotary or wireless type.

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