RU2055148C1 - Well demolition torpedo - Google Patents

Abstract

FIELD: mining industry. SUBSTANCE: torpedo charge is made of successively alternating members of high explosive of powder or pyrotechnic composition and explosive ensuring conversion of burning into detonation. Explosive ensuring conversion of burning into demolition is located in powder or pyrotechnic composition. Torpedo has additional layer of powder and/or pyrotechnic composition located under shall on charge external surface. EFFECT: higher efficiency and extended functional potentialities of torpedo due to generation of a series of periodically reiterating pressure pulses. 3 cl, 3 dwg

Description

 The invention relates to the mining industry, in particular to perforating-blasting operations in oil and gas wells, and is intended to shake stuck drill pipes, as well as call the inflows and increase the hydrodynamic connection of the formation with the well.

 The use of a borehole high-explosive torpedo, which, in the process of triggering, creates a series of successive shock-wave pulses, will significantly increase productivity and reduce wear on the cable, equipment and tools.

 Known selective perforating-explosive apparatus [1] containing several separately fired explosive charges (explosives) and means of their initiation, as well as an electromagnetic switch that provides undermining of charges in the required sequence. Each initiating means (detonator) is connected to a separate electric line exiting the switch.

 The disadvantages of this apparatus are the difficulty of installing an electric blast network, the high consumption of initiation means (one detonator per explosive charge), and relatively large (tens of seconds) times between detonation of individual charges.

 Closest to the proposed technical solution is a device [2] containing several elongated explosive charges in plastic tubes, on which steel sleeves are put on to periodically reduce the parameters of the shock wave affecting the structure of the well and the surrounding rocks. Each elongated charge has its own detonator with a given degree of deceleration. All detonators are activated simultaneously and initiate elongated charges with delays of 1.5-2.5 s.

 The disadvantages of such a system include the need to use many different detonators, the lack of separation in time of shock wave pulses during detonation within one elongated charge.

 The purpose of the invention is improving the efficiency and expanding the functionality of a borehole high-explosive torpedo.

To do this, in a known torpedo, lowered into the well on a single-core cable and including an elongated explosive charge and initiating means, the explosive charge is made in the form of sequentially alternating elements consisting of a blasting explosive, a powder or pyrotechnic composition and an explosive capable of translating the combustion process into detonation. Such a device during descent into the well and subsequent blasting provides:
treatment of a well in one run with a series of sequentially repeated shock-wave pulses generated by a torpedo with delays from one another within 0.1-5.0 s and more;
simplicity and safety of installation of the explosive chain and its reliability;
increasing the efficiency and likelihood of eliminating the accident in one launch of the torpedo.

 In addition, the proposed torpedo allows for processing of the borehole zone of the formation in a regime of cyclic controlled influences, each of which includes a shock wave impulse from a blasting explosive and a pressure impulse created by a burning powder or pyrotechnic element.

 The analysis of scientific and technical sources showed that it is not known to use the combination of distinctive features proposed in related fields of technology, which suggests that the proposed technical solution meets the criterion of "significant differences".

 Figure 1-3 presents a borehole high-explosive torpedo.

 In FIG. 1 shows a schematic diagram of the proposed torpedo. The torpedo contains a shell 1, for example, of aluminum, polyethylene or a heat-shrinkable polymer, combined as LH and other detonator 2, explosive elements 3 of a heat-resistant blasting explosive, for example, HMX-based elastite, powder or pyrotechnic elements 4, charges 5 of a special Explosive, which translates the combustion process into detonation, as well as a torpedo may contain an additional charge of gunpowder 4, which is located directly under the shell 1 along the entire length of the torpedo.

 Downhole high-explosive torpedo works as follows.

 The torpedo is mounted on a cable or logging cable, an “electric butt” detonator 2 is connected to it, which is connected to the electric line of the cable and is lowered into the well to a predetermined interval. When an electric pulse is applied to the circuit, a detonator is triggered, which excites detonation in the first element from the blasting explosive 3. After element 3 has completely detonated, it excites combustion in the next element 4, which is accompanied by intense gas evolution, and the specified period continues time depending on the length of the element and external pressure. After the combustion front reaches charge 5, the latter develops combustion, which within the same charge 5 goes into detonation. From charge 5, detonation is transmitted to the next element 3 from a blasting explosive, then the entire cycle is repeated. When at the initial stage it is required to obtain a slower increase in the pressure amplitude, the powder element 4 is installed first and the detonator 2 is attached to it.

 Figure 2 presents an embodiment of a torpedo, in which, to increase safety, a charge 5, providing the transfer of combustion to detonation, is placed completely inside the powder charge 4.

 In FIG. Figure 3 shows an embodiment of a torpedo intended primarily for processing the borehole zone of a formation. In it, under the shell 1, an additional powder element 4 is placed, which provides a reduction in the blasting effect of a torpedo and an increase in the intensity of exposure to powder gases.

 The proposed torpedo allows a wide range to change the gas dynamics of the explosive impact on the object and choose it depending on the type of technological operations performed in deep wells, as well as increase efficiency and expand the functionality of blasting.

Claims (3)

 1. Borehole explosive torpedo, comprising a supporting frame, means of initiation and explosive charge in the shell, characterized in that the charge along the length is made in the form of sequentially alternating elements of blasting explosive, powder or pyrotechnic composition and explosive, providing the transfer of combustion into detonation .  2. The torpedo according to claim 1, characterized in that the explosive, providing the transfer of combustion into detonation, is placed in a powder or pyrotechnic composition.  3. Torpedo according to claims 1 and 2, characterized in that the torpedo is equipped with an additional layer of powder and / or pyrotechnic composition, placed under the shell on the outer surface of the charge.

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