RU2396416C1 - Well string boring machine - Google Patents

Abstract

FIELD: oil and gas production.

SUBSTANCE: invention refers to oil and gas recovery, particularly - to a machine for removing a segment of a well string by electrochemical treatment. The well string boring machine accommodates a direct current power supply, electrodes, an electrolyte tank, a pipe valve for electrolyte injection, a dielectric pipe to inject electrolyte into the anodic dissolution zone and to sink a cathode cable. An anode is presented with the pipes, while a cathode is a special electrode connected within the removed pipe segment. The electrolyte is a conductor and during anodic dissolution, it is found in a zone of the cathode from any height. The cathode is shaped after the removed pipe segment. The cathode height is equal to the length of the removed pipe segment.

EFFECT: cutting time and reduced cost of removing the required pipe segment by metal anodic dissolution.

1 dwg

Description

The invention relates to the field of oil and gas production and can be used in the oil and gas industry.

Known riber to remove part of the casing [1]. Its disadvantages are: during prolonged operation, it becomes on the head of the shank and rotates together with the production casing without milling the pipe wall; if there is a threaded connection between the pilot riber and the shank, it is necessary to fix the latter, in order to prevent unscrewing, by means of a locking screw or to make the riber whole; the milling interval of some designs should be no more than 50-60 cm, since with a larger milling interval, the shank begins to work for wear; metal chips formed during milling fall on the bottom of the well, clogging it.

A device is known that implements the method of electrochemical processing of oil and gas wells, in which a direct electric current is passed through a multicomponent well mixture, and includes a cathode, which is a casing pipe, and an anode, which is a special electrode installed in the pipe perforation zone [2 ].

The disadvantage of this device is the impossibility of organizing the electrochemical process of dissolving the required part of the well string, since the multicomponent mixture does not have the desired composition and concentration of the solution.

The closest in technical essence to the claimed device is a device selected as a prototype that implements a method of influencing an oil reservoir containing a cathode, which is a well casing, and an anode, which is a special electrode installed in the perforation zone of the pipe. In this case, a constant voltage is supplied, which ensures the flow of electric current through the cathode, a multicomponent mixture of the well, the anode [3].

The main disadvantage of this device is the impossibility of organizing the process of electrochemical dissolution of the metal of the column, since the multicomponent mixture does not contain the required components and their required concentration.

The aim of the invention is to provide a device capable of destroying part of the column, for example in the field of perforation, by an electrochemical method.

This goal is achieved by connecting the casing (or any other) string to the positive pole of the current source, and a special electrode located inside the string at the level of the removed section to the negative pole, while inside the string, through a polyethylene pipe (or made of any other dielectric material) , an electrolyte is pumped, for example a solution of sodium chloride NaCl, to the upper level of a special electrode. When passing a constant electric current through the pipe, the electrolyte and a special electrode, anodic dissolution of the pipe section located opposite the special electrode will occur around its entire perimeter.

The essence of the claimed invention lies in the fact that the installation for the destruction of the well string in a certain area by electrochemical dissolution of the metal of the column includes a generator or any other source of constant electric current, a container for electrolyte with a tap, a pipe made of dielectric material, for example polyethylene, in which cable from the negative pole of the generator and through which electrolyte is fed into the treatment zone, a special electrode placed inside the column opposite the beats of the removed section with a certain gap, repeating the cross-sectional shape of the removed column, mainly round, and having a longitudinal size equal to the length of the removed section, while the destroyed column is connected to the positive pole of the electric current source, and a special electrode to the negative, through the cable in dielectric the pipe.

Comparative analysis with the prototype shows that the inventive installation is characterized by the presence of new elements and their relative position:

- a tank with electrolyte and a tap for opening and closing the pipeline;

- pipes made of dielectric material;

- electrolyte in the zone of removal of the column section;

- the shape of a special electrode that repeats the cross-sectional shape of the removed column, that is, basically round, and equal in length to the size of the removed section of the column in height;

- connecting the poles of the current source to the electrodes: the positive pole is connected to the column, and the negative to the special electrode.

Thus, the inventive installation meets the criteria of the invention of "novelty."

An analysis of the known technical solutions (analogues) in the study area allows us to conclude that there are no signs in them that are similar to the essential distinguishing features in the inventive installation, and to recognize it as meeting the criterion of “Significant differences”.

The application of all new features allows the proposed installation to remove part of the well string using an electrochemical method.

Figure 1 presents the installation diagram for the destruction of the well string. It contains a column 1, a pipe of dielectric material 2, a constant current electric power source 3, cables 4 and 5, a special electrode 6, an electrolyte tank 7, a valve 8. The positive pole of the power source is connected to the column 1 through cable 5, and the negative pole - with a special electrode 6 through cable 4.

Installation works as follows. The valve 8 is preliminarily opened, and the electrolyte from the tank 7 is drained through the pipeline into the upper part of the pipe 2, through which it fills the inner part of the column 1 to the upper level of the special electrode 6, which before this is located opposite the deleted section, then the valve 8 is closed. After that, the power source 3 is turned on, which ensures the flow of electric current along the circuit: “plus” of the power source 3, cable 5, pipe 1 of column 1, electrolyte inside the column, special electrode 6, cable 4, “minus” of the power source. When a constant electric current flows through the specified circuit, anodic dissolution of the wall of the column pipe takes place in the required section until it is completely dissolved through the wall thickness. The presence of a pipe 2 of dielectric material ensures that the electrolyte flows from the tank 7 along the wall of this pipe, and not along the wall of the column 1, and also ensures that the cable 4 does not touch the wall of the column 1, providing better insulation. After the destruction of the intended area, the power source 3 is turned off. Special electrode 6 and polyethylene pipe 2 are removed from the well.

The use of the claimed invention can significantly reduce the time required to remove the required section of the well string and reduce the cost of this operation.

Information sources

1. Gilyazov P.M. Drilling oil wells with sidetracks. - M .: Nedra, 2002 .-- 256 s.

2. RF patent No. 2087692, 1997.

3. RF patent No. 2163662, 2001.

Claims (1)

Installation for destruction of the well string containing a DC power source, electrodes, which are the pipe strings and a special electrode installed in the area of removal of the pipe section, characterized in that, in order to ensure anodic dissolution of the metal of the removed section of the pipe string, the installation is equipped with a tank with an electrolyte , for example, a solution of sodium chloride NaCl, and a valve for opening and closing the pipeline for supplying this electrolyte into the well string, as well as a small diameter pipe made of dielectric the material along which the electrolyte is supplied to the anode dissolution zone and in which the cathode cable is laid, which ensures its additional isolation from the electrode opposite in sign, and the special negative electrode is made in the form of a removed pipe section from its inner side in a removed cross section and in height equal to the length of the removed section, while this electrode is connected to the negative pole of the source of constant electric current, and the pipe of the column to the positive the pole, and, in addition, in the area where the special negative electrode is located, there is an electrolyte that has come across the entire height of the electrode from the tank through a dielectric pipe and is a conductor of direct electric current through the circuit: “plus” of the power source, column pipe, electrolyte, special electrode, “ minus "the power source, which provides anodic dissolution of the metal walls of the pipe columns in the desired area.

Images