SU1010586A1 - Well-logging instrument - Google Patents

Abstract

1. BACKGROUND OF THE ACOUSTIC CARRIAGE, containing a three-element acoustic probe with receivers and radiators, separated. acoustic insulators, centralizers, electronic circuitry, and so on, so that, in order to expand the range and improve the accuracy of determining the recorded rocks, the receiver is located in the lower part of the device and is separated from the radiator closest to it Connected by an acoustic absorber and an acoustic simulator, one of the centralizers is mounted on the acoustic isolator and separated from the receiver by an acoustic absorber, and the electrical circuit is located in the upper part of the instrument, 2. according to Claim. 1 of t n and v and w soup and in that an acoustic absorber is designed as a hardwired rubberized section with a deep groove, {yzdel yushey connecting elements in the form of cup, the bottom and the cylindrical wall kotoryhimeyut rows of through holes. sl 00 Oi

Description

This invention relates to a geophysical survey technique for exploration wells. There are several variants of the layout of the downhole tool, which includes a three-element acoustic zone with a receiver and radiators, which are divided by acoustic insulators, centering devices, and an electronic circuit, containing generating and amplifying units. Constructive. The performance, parameters and relative position of the main units of the downhole acoustic logging tool determine to a significant extent the range and accuracy of the recorded rock parameters: The well known SPAK-4 acoustic well logging device is known, containing the following main nodes located downwards (from the cable connection side): a generator electronic unit, two radiators and a receiver separated by acoustic isolators, an amplifying electronic unit. Acoustic isolators are made in the form of a rubberized steel pipe with transverse through slots located in a chessboard order. The centering devices in the form of rubber rods are installed perpendicular to the axis of the device in several lars. Restrictions on the use of this wellbore device are caused by the insufficient effectiveness of acoustic isolators that prevent measurements in rocks in which the velocity of the piac space of elastic waves is lower than 2300 m (for example, in weakly compacted clays), the poor quality of centering of the device due to the use of nonrigid centralizers, increasing the length and weight of the device due to the separation of the electronic circuit n. the generator unit and the amplifier unit, spaced above and below the acoustic probe. A device for centering acoustic logging instruments is known that contains more rigid spring centralizers with movable bushings mounted on tubes at the ends of the instrument, the centralizer on the receiver side being separated by an additional acoustic insulator t 1 The drawbacks of such an arrangement of an acoustic logging instrument are due to the centralizers being moved out of the acoustic probe and an electronic unit and installing an additional acoustic isolator. Increasing the distance between the upper and lower centralizers, as well as the overall length of the device and its mass, leads to an increase in the acoustic probe deflection, displacement of the emitters and receiver from the borehole axis and a decrease in the accuracy of recording rock parameters. Closest to the proposed technical entity is a borehole acoustic acoustic logging, in which the emitter and receivers are separated by an acoustic insulator assembled from elements such as vertebrae and installed inside a parallel coupled second acoustic insulator in the form of a pipe cut through through transverse grooves the location of the bearing design of the acoustic probe. The blocks of the electronic circuit and the spring centers are moved beyond the limits of the acoustic probe Z.. The disadvantages of this downhole tool are the complexity of the design of the acoustic probe, the lack of effectiveness of the external acoustic isolator, the increase in the length and weight of the instrument due to the placement of a part of the electronic circuit and one of the centralizers below the acoustic probe, which leads to deterioration of centering and reduction in the accuracy of the recorded rock parameters. The purpose of the invention is to expand the range and improve the accuracy of determining the recorded parameters of rocks. The goal is achieved by the fact that in a well device containing a three-element acoustic probe with a receiver and radiators separated by acoustic insulators, centralizers and an electronic circuit, the receiver is placed in the lower part of the instrument and separated from the source to it by a radiator successively docked with an acoustic absorber and an acoustic isolator, one of the centralizers is installed on the acoustic isolator and is separated from the receiver by an acoustic absorber, and the electronic circuit is located in the upper part of the instrument. The acoustic absorber is made in the form of rubberized sections connected to the thread with a deep groove separating the connecting elements in the form of glasses, the bottom and cylindrical walls of which have a row of through-holes. FIG. 1 shows a downhole tool, a general view; in fig. 2 is a section A-A in FIG. one; in fig. 3 is a section BB in FIG. one; in fig. 4 shows a section B-B in FIG. 1. In the upper part of the downhole tool (Fig. 1), an electronic unit 1 is located in a single protective housing, containing an electronic circuit for initiating radiators 2 and 3 and an amplifier. The electronic unit 1 has a head for connection with. cable lug, and below it articulates with the probe part. The acoustic probe has two radiators 2 and 3 and the receiver 4, separated by acoustic insulators 5 and 6, and acoustic insulating absorber 7, acting as a carrier-structure. The acoustic isolator 5, installed within the pacctode or between radiators 2 and 3 (the base of the probe), is a two-pipe structure with transverse through slots arranged in a staggered pattern. The inside and outside of the structure is covered with a layer of rubber filling the grooves and gaps in it. The acoustic isolators 6 and 7, located within the distance between the receiver 4 and the radiator 3 closest to it (probe length), are a combination of different insulators. types. By device, isolator 6 is identical to isolator 5. They are. are predominantly a delay line for wave-interference. Let us call them acoustic insulators, in contrast to the acoustic absorber torus 7, which has a high absorption efficiency of an elastic wave propagating through it. The device is equipped with spring-type rigid centering devices 8, one of which is mounted on the acoustic insulator 6 and separated from the receiver by an acoustic absorber 7. The other centering device is placed on the protective casing of the electronic unit 1. If necessary, a third unit can be placed on the electronic unit. a centering device to provide a more secure retention of the instrument on the axis of the wells with large inclination angles. The acoustic absorber isolator 7 (Fig. 2) is made in the form of interconnected sections 9, forming a metal frame. The skeleton is pressed by rubber 1O, possessing sound absorbing properties. Section 9 has a deep annular groove 11, which separates the threaded connecting elements 12 and 13 in the shape of glasses. The bottom of the glasses and their cylindrical walls have a row of through holes 14. Acoustic by, the absorber has a central hole J.5 for routing the connecting wires through it. The length of this "csustic absorber is chosen to be equal to 0.2-O, 5 anti-probes S due to the condition of the necessary degree of attenuation of noise and interference. Its effectiveness is ensured; by extending the path of the elastic wave, multiple reflection and scattering at the boundaries with different acoustic rigidity, as well as significant penetration of wars in a wide frequency band due to alternations of narrowed and enlarged; on the diameter of the frame elements. The effect of wave absorption occurs due to the carving of the carcass. The tracing wires 16 (FIG. 3) from the receiver 4 to the electronic unit 1 are laid in the central hole 15 of the acoustic insulators 5-7. The wires 16 of the receiving path are shielded from the drivers 2 and 3 and the wires 17 connecting them with the electronic unit 1 and the insulator 5 which are laid in the channel 18 of the external rubber cutter. A double-pipe steel frame 19 of the two-pipe acoustic insulator 5 is used as the electromagnetic shield. Fig. 4 shows the articulation unit of the probe part of the device with the electronic unit 1. The coupling elements 2O and 21 are mechanically connected with a cap nut 22. The assembly is sealed against the seal. rings 23. An electrical connection is made through two groups of plug connectors, including contact pins 24 and contact sockets 25. Connector plugs 24 are combined with sealed electrical wires separating the air cavity inside the protective casing of the electronic unit 1 from the filled with electrically insulating liquid 26 cavity with borehole pressure; leniem. To increase the reliability of electric; wounding contact groups of connectors of receiving-amplifying and radiating paths are spaced apart in diameter to the length of the device and placed in the end portions of the stepped connecting elements 20 and 21, which have central 27 and 28 and external 29 and 30 holes re-divided by a metal wall . Measurements are made when the instrument is raised in the well. Recipients 2 and 3 are alternately driven by current pulses. Receiver 4 senses all types 51O of elastic waves excited in the borehole and in the well; and including rasprosgran yushiye on the borehole wall {recorded useful / signal), flushing fluid (hydraulic), probe body (wave interference), as well as noise from the movement of the instrument. The arrival time of the useful signal depends on the speed of propagation of elastic waves in the rock and flushing fluid, the size of the acoustic probe and the diameter of the well. In acoustic heading on the head waves, it should be possible to record the useful signal in the whole range up to devices based on rigid acoustic insulators, the wavelength of the noise on the probe body is greater than the speed of the hy-wave (their values are 2200 m / s and 1650 m / s, respectively). . In the proposed device, the wave-noise in the probe body is attenuated in amplitude to the level of mechanical noise from the movement of the device and delayed in time before the arrival of the hydraulic wave, which is achieved by combining successively coupled acoustic insulator and acoustic absorber. The level of noise from the instrument in the well is significantly reduced, which is ensured by the placement of the receiver assembly in the lower part of the instrument and increased interference with its implementation. Reliable shielding of the communication link of the receiving amplifier tract makes the pickup from the excitation pulse of emitters durability shorter than the time of arrival of the useful signal in the highest-speed rocks. This provides the ability to register reservoir velocities in the entire range up to their values in the flushing fluid. Placing the electronic excitation circuit and emitters and amplifier in a single protective housing, installing one of the centers on the acoustic insulator within the length of the acoustic probe reduces the length and length of the instrument, improves the quality of the centering. The latter provides an improvement in the quality of the recorded time and amplitude parameters, and this is most pronounced in inclined wells and in sections with a large attenuation of elastic waves, such as fractured reservoirs and weakly compacted clays. In general, all this provides an improvement in the metrological and operational characteristics of an acoustical downhole tool, expands its field of application for solving various geological problems, in particular, for the qualitative separation of fractured reservoirs, the selection of zones of abnormally high reservoir pressure, and the determination of pore pressure values.

FIG. 1

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FIG:

Claims (2)

1. Downhole tool ACOUSTIC BARREL, containing a three-element acoustic probe with a receiver and emitters, is divided. acoustic insulators, centralizers, electronic circuitry, with the fact that, in order to expand the range and improve the accuracy of determining the recorded parameters of rocks, the receiver is located at the bottom of the device and is separated from one of the emitters closest to it, jointly coupled, by an acoustic absorber and an acoustic insulator, one. of the centralizers is mounted on an acoustic insulator and separated from the receiver by an acoustic absorber, and the electronic circuit is located in the upper part of the device, ₍ 2. The device according to π. 1, about t and h and y. This is due to the fact that the acoustic absorber is made in the form of rigidly connected rubberized sections with a deep groove separating connecting elements in the form of glasses, the bottom and cylindrical walls of which have rows of through holes. SU „..1010586