RU2439620C1 - Pulsed powder elastic wave source - Google Patents

Abstract

FIELD: physics. ^ SUBSTANCE: disclosed is a pulsed powder elastic wave source consisting of a cartridge chamber, a receiver, a bar, a protective disc, cross pieces with handles, a generating element which is in form of an impact mechanism which provides mechanical activation of capsule of the blank cartridge. The impact mechanism is provided with a safety mechanism in form of a fork. The cartridge chamber has a narrowing inside in form of a rectangular ledge. The muzzle part of the cartridge chamber is in form of a cone which expands in the direction of the muzzle end. A stop piece is placed at the lower end part of the cartridge chamber. The bar is provided with a seal which is comparable with the diameter of the well. The cartridge chamber and the receiver are connected by a multiple thread. ^ EFFECT: high efficiency of seismic exploration by widening the spectrum of excited vibrations and high energy of single effect of powder gases on the ground in a shallow well. ^ 3 dwg

Description

The invention relates to geophysical equipment, providing a process for the excitation of elastic vibrations during seismic exploration. The main areas of application are shallow high-resolution seismic exploration in mineral deposits and engineering seismoacoustics for solving problems of engineering and geological surveys.

Two types of pulsed sources — shock and explosive — are used in seismic exploration of shallow depths [1]. For example, the following types of shock sources are known: falling load [2], spring [3], hydraulic [4], pneumatic [5]. These sources are characterized by the following general disadvantages: they have significant dimensions and weight, i.e. not mobile in difficult terrain and woodland; require significant physical labor or special vehicles to move along the profile; require special additional energy sources (batteries, compressors, gas units) for lifting the hammer striker; working out the physical observation point is carried out over a significant time period; have a high probability of a double hit with a single exposure.

Explosive sources of oscillations in shallow and engineering seismic exploration are extremely rare. This is due to the danger of transporting blasting explosives, the need for equipment and the protection of explosive depots, the danger of explosions near the earth's surface, low efficiency and the inability to use it in urban agglomerations.

The most successful known example of a pulsed explosive source of oscillations for the purposes of shallow seismic exploration is a seismic gun [6]. In a seismic gun, the energy of the release of powder gases in a shallow well is used to generate elastic vibrations in the soil. Mostly used is a charge of smoke powder, which is equipped in standard cartridges of hunting cartridges of 12 caliber.

The closest in technical essence to the proposed is US patent No. 4867266 [7], which is adopted as a prototype. The device is designed to excite seismic signals in the ground with the explosion of one or more cartridges. A tubular barrel (underground part of the device) made of a brittle material, such as plastic, has a fixed cartridge inside, the cartridge has a head with an electrically excited capsule. Inside the barrel, an extension block is fixed, which provides electrical communication with the cartridge and the capsule. The wires are connected to the electrically conductive block and pass further along the outside of the barrel; the cartridge explodes by connecting to a current source. The barrel can be extended by attaching a plurality of additional cartridges located at a distance from each other, the first cartridge is electrically actuated, the remaining cartridges explode under the influence of an impact. Each impact cartridge is connected to a plunger, which is driven by a bullet (core), fired from the previous cartridge; Thus, after the explosion of an “electric” cartridge, its bullet activates the first “shock” cartridge, and then each shock cartridge explodes sequentially. In this device, the first cartridge may be impact, driven by a rod brought to the surface of the earth.

The disadvantage of the prototype is that the entire underground part of the device ("trunk"), consisting of many specially made parts, is intended for single use and is completely destroyed with each actuation of the source. Such a number of special parts objectively determines the significant cost of one physical point.

The disadvantage of the prototype is the need to use an additional device - a battery that provides initialization of the charge. This leads to a significant weight of the source and its low mobility. The electric option to initialize a special igniter capsule implies high-quality isolation of the internal parts of the device from the penetration of dirt and moisture, which is not always possible in the field - swamp, rain, snow, filled with water and liquid mud from the well. A significant disadvantage of the prototype is the significant recharge time due to the slow installation of the electrical contacts of the first cartridge, the strikers of the subsequent cartridges and individual destructible (plastic) parts of the barrel.

The known device uses cartridges containing, in addition to a powder charge, and a massive metal shell (firing pin) - a bullet weighing 3 ounces (about 85 grams), which is dangerous for service personnel in the event of an unintentional operation of the device outside the well. Also, the device cannot be certified for safety in the Russian Federation, because It is not equipped with a fuse and does not provide protection when throwing a propellant charge in case of an accidental shot on the day surface.

In the known device there is no seal between the walls of the well and the tubular body of the source, which prevents energy loss due to the release of soil and gases to the earth's surface. As a result, the energy indicators of the generated seismic pulse are reduced, and there is a danger of the emission of soil particles and gases along the walls of the well towards the operator.

In the known solution, it is possible to use the first (one) cartridge as a percussion cartridge, driven by a rod brought to the surface of the earth. But this option also requires a bullet in the cartridge to create gas pressure, and the cartridge itself is still placed in a completely destructible (plastic) part of the barrel.

In addition, a disadvantage in the known solution is that part of the energy of the powder gases of each cartridge is spent on accelerating a massive bullet and subsequent destruction of the barrel walls made of brittle material, which leads to a stretching of the pulse in time and a decrease in its energy, as well as to lowering the frequency range of excited vibrations.

The combination of these shortcomings does not allow the use of a well-known source for seismic exploration of shallow depths with sufficient efficiency and efficiency, requires significant material costs, virtually eliminates the possibility of its use in difficult rugged swampy terrain, does not provide safety standards adopted for the corresponding devices in the Russian Federation, and also has insufficient dynamic indicators for conducting high-resolution seismic surveys on reflected waves.

The technical result of the invention is to increase the efficiency of seismic exploration in the study of shallow depths due to greater mobility and efficiency of working out a physical point, expanding the spectrum of excited vibrations and increasing the energy of a single exposure of powder gases to the soil in a shallow well, reducing application restrictions due to surface conditions, increasing safety operation of the device, ensuring prolonged reuse of the device.

The above technical result is achieved due to the fact that in a pulsed powder source of elastic vibrations, consisting of a chamber, receiver, rod, protective disk, crosspiece with handles, a generating element, according to the invention, the generating element is made in the form of a percussion mechanism, providing mechanical initiation of the empty capsule cartridge, while the percussion mechanism is equipped with a safety device in the form of a plug, the chamber inside has a narrowing made in the form of a ledge of a rectangular shape, while ulnaya part of the chamber is formed as a cone expanding in the direction of the muzzle on the lower end portion of the bolt mounted stop bracket, the rod is equipped with a rubber sealant, comparable to the diameter of the well, the connection chamber and receiver implemented using multiple thread.

The combination of distinctive features allows for a delay of wad-shutters with their subsequent destruction during the shot, while the forcing pressure necessary for the full and maximum rapid combustion of the charge of smokeless hunting gunpowder develops. This allows you to maximize the energy of the generated pulse and reduce its duration, due to which the expansion of the spectrum of excited oscillations is achieved. The implementation of the muzzle of the chamber in the form of a conical expansion (nozzle) provides a uniform distribution of powder gases over the volume of the bottom of the well, which reduces the amount of irreversible plastic deformation of the soil, which reduces the resulting vibrational excitation energy.

The claimed pulsed powder source of elastic vibrations is a long-term reusable device. Consumables are only blank cartridges.

The thrust bracket located at the lower end of the chamber is a protection against the throwing of the projectile element from the barrel when it is unauthorized, provides a constant distance between the muzzle section of the chamber and the bottom of the well and prevents clogging of the muzzle section with soil, thereby increasing the stability of energy indicators of the pulse from shot to shot.

When the device is installed in the working position, the sealant tightly closes the wellhead and, together with the movable protective disk, prevents the release of powder gases and soil particles along the wellbore towards the operator.

A safety device in the form of a fork that locks the drummer’s rod prevents the device from tripping during transportation and in preparation for firing.

The device can be used without restrictions in any soil, including in a swamp, in wells flooded with water and contaminated.

In this version, the claimed device can be certified according to safety standards adopted in the Russian Federation.

Pulse powder source of elastic vibrations in this design ensures the achievement of a technical result.

Figure 1 presents a General view of the claimed device, figure 2 shows the internal view of the chamber, figure 3 shows examples of wave fields and their spectra for different sources.

The pulse powder source of elastic vibrations consists of a chamber 1 with a thrust bracket 2 at the lower end, a receiver 3, a shock mechanism body 4 with a metal button 5 at the upper end, a rod 6 with a rubber seal 7, a movable protective disk 8, a cross with handles 9 and a safety a device in the form of a plug 10. The inside of the chamber has a narrowing in the form of a ledge 11 of a rectangular shape, and its muzzle is made in the form of a cone expanding in the direction of the muzzle cut 12. The chamber is connected to the receiver by gozahodnoy thread 13.

Mechanical initialization (pricking) of the cartridge is carried out by striking with a light hammer on a metal button 5 located on the upper end of the rod passing inside the rod 6.

The rubber seal 7 located on the rod 6 has a diameter comparable to the diameter of the well, thus when the device is in the working position it tightly closes the wellhead and prevents the release of powder gases, which ensures a more complete transfer of shot energy to the ground, and therefore, the depth increases penetration of seismic signals.

The protective disk 8 is made of plastic or hard rubber and moves freely along the rod 6. During the excitation of vibrations, it additionally compacts the well and eliminates the emission of soil particles towards the operator, ensuring its safety.

The crosspiece with two rubber handles 9 provides a convenient and safe hold of the device during operation.

Inside the chamber 1 of the inventive device (figure 2) there is a transition of the inner diameter in the form of a ledge 11 of a rectangular shape from a larger diameter (outer diameter of the cartridge) to a smaller one (diameter of the bore). The step 11 provides for the delay of the wad-shutters with their subsequent destruction during the shot, while the forcing pressure necessary for the full and maximum rapid combustion of the charge of smokeless hunting powder develops. According to bench tests, with this design, the boost pressure increases by at least 3 times, which in turn allows you to maximize the energy of the generated pulse, reduce its duration and expand the spectrum of excited vibrations.

The muzzle part of the chamber 1 is made in the form of a conical expansion (nozzle) in the direction of the muzzle section 12. The proposed shape of the outlet ensures a uniform distribution of powder gases over the volume of the bottom of the well, which reduces the amount of irreversible plastic deformation of the soil, which reduces the resulting vibrational excitation energy.

At the lower end of the chamber there is a stop bracket 2, which, in case of unauthorized loading of the throwing element into the cartridge, prevents its ejection from the barrel, ensures a constant distance between the muzzle section of the chamber and the bottom of the well and prevents clogging of the muzzle section by soil, thereby increasing the stability of the pulse energy indicators from shot to shot.

The connection of the chamber 1 and the receiver 3 is carried out by multi-thread 13, which provides high locking strength and the ability to quickly replace the spent cartridge case with a new charged cartridge. The duration of the recharge of the source is not more than 30 seconds.

In the upper end part of the rod 6 there is a safety device in the form of a fork 10 that locks the rod of the percussion mechanism, which ensures safe handling of the device during transportation and in preparation for the shot.

The proposed device operates as follows.

Along the seismic profile at each picket (physical point), a hole with a diameter of 6 cm (comparable to the diameter of the o-ring) and a depth of 50-100 cm is drilled with a manual or portable motor drill. The proposed source of vibrations is inserted into the well. At the command of the operator of the seismic station, the source operator, holding the cross 9 with his hand and the protective disk 8 with his foot, strikes the metal button 5 with a light hammer, after which a special blank cartridge is initialized. Gases released during sharp combustion of smokeless powder hit the bottom of the well, thereby exciting elastic vibrations in the soil. These oscillations are recorded by seismic sensors placed along the profile. After working out the physical point, a transition to the next one takes place, during which the source is recharged. The operator unscrews the chamber 1, removes the spent sleeve, inserts a new cartridge, tightens the chamber 1, puts the source in the well pre-drilled at the next picket.

For the operation of the device, specially equipped idle cartridges in a 12-gauge plastic sleeve with a charge of smokeless powder intended for use in shot hunting cartridges and plastic wad-obturators that are destroyed during the firing are used.

The claimed device was used during shallow seismic exploration at the Verkhnekamsk potassium-magnesium salts deposit. More than 20,000 physical points have been tested in various surface and weather conditions.

As a result of using the claimed device, the registered wave fields made it possible to study the structure of the rock mass to a depth of 500 m with more detail, and the time spent on running a running kilometer of the profile was reduced by a factor of 1.5. The width of the spectrum of the excited oscillations reached 100 Hz and significantly exceeded the similar characteristics of other types of sources. Figure 3 in comparison shows the wave fields and their spectra for the types of sources: a - incident load of 40 kg from a height of 2.5 m; b - mechanized source "GeoStrike" (USA); in - the claimed device.

Thus, the pulsed powder source of elastic vibrations in the claimed performance ensures the achievement of a technical result. The technical result is an increase in the effectiveness of field seismic exploration in the study of shallow depths, is as follows:

- increasing the mobility of the device by eliminating additional power generating devices (batteries);

- reduction of the time spent on developing a physical point due to the speed and simplicity of recharging;

- expanding the spectrum and increasing the energy of the excited pulse and, accordingly, the resolution and depth of research;

- increase the level of safety during operation of the device;

- reduced application restrictions due to surface conditions;

- low cost of cartridges made using standard, generally available components.

The industrial applicability of the claimed device is not in doubt, the more it allows you to abandon heavy shock sources, cartridges equipped with a propelling charge, to use repeatedly and in any conditions. The claimed device has passed certification No. ROSS RU.SA02.B11988), according to which it complies with TU 4314-004-04538067-2007 and meets the requirements of GOST R 50529-93 and TU 4314-004-04538067-2007 for strength and safety.

Information sources

1. Nikitin V.N. Fundamentals of engineering seismic. - M., Publishing House of Moscow State University, 1981.

2. Schneerson MB, Mayorov VV Ground seismic with non-explosive sources of oscillation. - M .: Nedra, 1980.

3. Impose VV, Popov A.Ya., Dick P.I. Seismic exploration of shallow depths. - M .: Nedra, 1989.

4. Patent of the Russian Federation No. 2322685, cl. G01V 1/147, 2006.

5. Patent of the Russian Federation No. 2246740, cl. G01V 1/147, 2002.

6. Miller R. D., Pullan S. E., Waldne J. S., Haeni F. P. Field comparison of shallow seismic sources // Geophysics. 1986. V. 51, P.2067-2092.

7. US patent No. 4867266, IPC G01V 11/04, 1989.

Claims (1)

An impulse powder source of elastic vibrations, consisting of a chamber, receiver, rod, protective disk, crosspiece with handles, a generating element, characterized in that the generating element is made in the form of a shock mechanism that provides mechanical initiation of the blank cartridge, while the shock mechanism is equipped with a safety device in the form of a plug, the chamber inside has a narrowing made in the form of a ledge of rectangular shape, while the muzzle of the chamber is made in the form of a cone, expanding in muzzle cut, on the lower end of the chamber there is a stop bracket, the rod is equipped with a rubber seal comparable to the diameter of the borehole, the chamber and receiver are connected using multi-thread.

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