RU2499123C2 - Spring centraliser with automatic locking at casing string - Google Patents

Abstract

FIELD: oil-and-gas industry.

SUBSTANCE: spring centraliser to be automatically locked at casing column consists of centering plates and two seamless rings. Ends of said seamless rings are jointed by weld seam. Note here that lower ring has special inclined two-six pockets (depending upon centraliser size). Said inclined pockets accommodate two forged rolls coupled by torsion spring locked by retainer in transport position. Centraliser locking in rolls displacement by the spring in wedge pocket after removal of retainer is effected by the principle of overrunning coupling. Wedge pocket is formed by centraliser ring and casing column. One roll lock centraliser against downward displacement while another one inhibits upward displacement.

EFFECT: perfected design.

2 dwg

Description

The invention relates to the oil and gas industry, in particular casing fastening of wells while drilling for oil and gas.

Known centralizer, consisting of two steel rings, which are rigidly fastened to each other by spring arched strips [1]. Their fixation on the casing is achieved by placing a centralizer on both sides of the casing sleeve.

The disadvantage of this design is the low centering ability, limited patency along the wellbore and high metal consumption.

Known hard centralizer with freedom of rotation on the casing, fixed from movement along the pipe by two rings [2]. Such a centralizer allows you to rotate the casing during cementing, which improves the quality of fastening.

The main disadvantage of such a centralizer is its low cross-hole ability.

Known centralizer, consisting of centering strips attached to rings placed on the casing, and a locking device located inside the rings of the centralizer. The locking device is made in the form of a locking ring having stoppers [3]. Around the axis of the stoppers, the ring is rotated (swinging) and due to this skew, the centralizer is fixed on the casing.

The disadvantage of this centralizer is the difficulty of installing the retaining ring inside the centralizer when mounted on the casing.

Known spring centralizer, comprising two fasteners and spring bars connected to them, made of one-piece, while in the lower fastener there are threaded holes in which are installed fixing screws with sharp chamfers, which allow securely fastening the centralizer to the casing [4].

The main disadvantage of this centralizer is the duration of the fixation on the casing, as it is necessary to tighten several screws.

The aim of the invention is to provide a centralizer for centering casing, providing centering of the casing in the well and automatic fixation of the centralizer on the body of the casing.

This goal is achieved by the fact that in the spring centralizer, consisting of centering strips and two whole-cut shells, the ends of which are connected by a weld, special inclined pockets are made in the lower shell (from two to six - depending on the size of the centralizer), in which two hardened rollers connected by a torsion spring fixed in the transport position by a check (lock), the centralizer is fixed on the casing by moving the rollers using the spring along the wedge groove (pocket), formed by the centralizer shell and casing after removing the checks (retainer) according to the principle of overrunning clutch care, with one roller fixing the centralizer from moving down and the second up, thus the technical result is a reliable fastening of the centralizer to the casing with a significant reduction in fixing time, since the fixing process itself is reduced to simple removal of the checks (latch) and the resulting automatic fastening of the centralizer to the casing.

In FIG. 1 shows a structural diagram of a centralizer, and in FIG. 2 is a diagram of a centralizer installation on a casing string.

This combination and the shape of the centralizer elements allow you to maintain its fixed position on the casing.

The analysis of the prior art, including a search by patent and scientific and technical sources of information, allowed to establish that the applicant has not found an analogue corresponding to the features of the claimed invention.

Therefore, the claimed method and device meet the requirements of "novelty."

The claimed method and device are not obvious and do not follow for a specialist explicitly from the prior art.

Therefore, the claimed method and device meet the requirement of "inventive step" under applicable law.

The drawings show:

FIG. 1 is a structural diagram of a centralizer. Figure 2 - technological installation of the centralizer on the casing.

FIG. 1 - casing 1, a centralizer with fixation elements on the casing.

FIG. 2 - casing 1, lower centralizer shell with a special stamping 2, torsion spring (shown in the locking position of the centralizer of the check removed) 3, roller (shown in two positions - transport and locking position thinly) 4, check 5.

Information sources

1. Bulatov A.I., Avetisov A.G. Handbook of a drilling engineer. In 2 volumes, Volume 1. - M., Nedra, 1985, p. 328.

2. Composite catalog of oil filld equipment & services, 43 rd edition 1998-1999, in 2 volumes, 1 vol., A Gulf pablishing Company Pablication, p. 483.

3. Patent RU 2224871 C2.

4. Patent for utility model No. 91737.

Claims (1)

The spring centralizer with automatic fixation on the casing consists of centering strips and two whole-cut shells, the ends of which are connected by a weld, with special inclined pockets in the lower shell, from two to six, depending on the size of the centralizer, in which there are two red-hot rollers connected by a torsion spring fixed in the transport position by a check-lock, the centralizer is fixed on the casing by moving the rollers with the spring along the wedge groove at the (pocket) formed by the centralizer shell and the casing after removing the locking pins, according to the principle of the overrunning clutch, with one roller securing the centralizer from moving down and the second up, so the technical result is a reliable fastening of the centralizer to the casing with significant reduction of fixing time, since the fixing process itself is reduced to simple removal of the locking pins and the resulting automatic fastening of the centralizer on the casing.

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