RU2282706C1 - Casing pipe shoe - Google Patents

Abstract

FIELD: mining, particularly to lower casing pipe in well bore during well construction.

SUBSTANCE: casing pipe shoe comprises hollow cylindrical body provided with connection thread at upper part thereof. The connection thread is adapted to connect the body to casing pipe. Guiding plug having axial channel, through axial slots and conical lower part is fixedly secured to the body. The shoe also has deflecting members and fingers. The deflecting members are made as bent double-armed levers having T-shaped cross-sections. Each lever includes base and support plate. Outer surface of support plate defines round billet sector in cross-section. Lever bases are located in through axial slots of guiding plug. Guiding plug and lever bases are provided with radial channels for finger receiving. The levers are uniformly installed on outer side surface of guiding plug by means of fingers and may rotate about the fingers. Major lever arms are directed towards lower end of guiding bush, minor ones are directed towards the body.

EFFECT: increased reliability of casing pipe lowering and installation in abnormal well bore.

2 cl, 4 dwg

Description

The invention relates to the mining industry and can be used to lower the casing string into the wellbore during its construction.

Known column shoe, consisting of a cylindrical body with a connecting thread at the upper end and through radial channels. The housing is rigidly connected with a guide plug with a rounded lower end made of easily drilled material [1].

However, the known device, due to its design features, does not provide sufficient passability of the casing when it is lowered into a complicated wellbore.

A well-known casing shoe, including a hollow cylindrical body, having in the upper part a connecting thread for connection with the casing, and a guide plug rigidly connected to the body with an axial channel, with through axial grooves and a conical lower part [2]. The specified device can be taken as a prototype.

The disadvantages of the known device should also include the likelihood of not allowing the casing to the design depth in the complicated (having kinks, cavities, ledges, troughs, etc.) of the wellbore.

The objective of the present invention is to improve the reliability of the descent and installation of the casing in a complicated wellbore.

This goal is achieved in the proposed technical solution due to the fact that the casing shoe, including a hollow cylindrical body with a connecting thread in the upper part for connection to the casing, a guide plug rigidly connected to the body and having an axial channel, through axial grooves and a lower conical the part is equipped with fingers and deflecting elements made in the form of curved two-arm levers of a T-shaped section, each of which consists of a base and a base plate, the outer surface of which Oh in cross section has the form of a sector of a tube billet. The base of the levers are installed in the through axial grooves of the guide tube. Radial channels are made in the guide plug and in the bases for placing fingers therein. The levers are evenly mounted on the outer side surface of the guide plug with the help of fingers with the possibility of rotation around them, with the large shoulders of the levers directed towards the lower end of the guide plug, and the small ones toward the body. The length of the large shoulder of the lever can be several times greater than the length of its small shoulder.

The shoe structure is illustrated by drawings, where FIG. 1 shows a general view of a shoe in a transport position, and FIG. 2 shows a general view of a shoe in a working position.

The casing shoe consists of a hollow cylindrical body 1, in the upper part of which a connecting thread is made for connection with the casing (not shown in the drawings). A guide tube 2 is rigidly connected to the housing 1 with an axial channel and a conical lower part. The guide plug is usually made of easily destructible material.

In the guide plug 2 there are through axial grooves for accommodating deflecting elements in them, which are made in the form of curved two-arm levers of a T-shaped section. The length of the large shoulder of the lever can be multiple times the length of the small shoulder.

Each lever consists of a base 3 and a base plate 4, which are rigidly interconnected. The outer surface of the base plate 4 in cross section has the form of a sector of a tube billet.

The levers are evenly mounted around the outside of the guide plug 2, connected with it using fingers 5 and have the ability to rotate around them. To accommodate the fingers 5 in the bases of 3 levers, as well as in the guide tube 2, radial channels are made. The bases of the 3 levers are installed in the axial grooves of the guide plug 2, and the base plates of the 4 levers are outside it.

The levers are installed in such a way that their small shoulders are turned towards the housing 1, and the large shoulders are towards the lower end of the guide tube 2.

The proposed device operates as follows.

The lower end of the casing string is equipped with a shoe before it is lowered into the wellbore. When passing through the complicated part of the trunk, in which sharp bends, cavities, ledges, grooves, etc. can occur, the deflecting elements provide the possibility of self-orientation of the shoe, thereby increasing the likelihood of lowering the casing without complications and accidents. The interaction of the large shoulder of one of the levers (or at the same time two or three levers) with the wall of the wellbore leads to the appearance of a certain moment of rotation on it, due to which the lever is rotated around finger 5. At the same time, the small lever shoulder with an effort that is a multiple of the force acting on the large lever arm, rests against the wall of the wellbore, pushing the shoe away from it. This ensures the self-orientation of the casing shoe relative to the wellbore.

Information sources

1. K.V. Johansen. Directory. Driller's satellite. M., Nedra, 1990, p. 159.

2. E.M. Soloviev. Well completion. M., Nedra, 1979, p. 171.

Claims (2)

1. The casing shoe, comprising a hollow cylindrical body, having in the upper part a connecting thread for connection with the casing and a guide plug rigidly connected to the body with an axial channel, through axial grooves and a conical lower part, characterized in that it is equipped with deflecting elements and fingers, and the deflecting elements are made in the form of curved two-arm levers of a T-shaped section, each of which consists of a base and a base plate, while the outer surface of the base plate in pop the river section has the form of a sector of a tube billet, with the base of the levers installed in the through axial grooves of the guide plug, and the guide plug and the base of the levers have radial channels for placing fingers in them, while the levers are evenly mounted on the outer side surface of the guide plug with the fingers with the possibility of rotation around them, and the large shoulders of the levers are directed towards the lower end of the guide tube, and small - towards the body. 2. The casing shoe according to claim 1, characterized in that the length of the large arm of the lever is several times greater than the length of its small arm.

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