GB2134613A

GB2134613A - Production-tube connection for an oil well

Info

Publication number: GB2134613A
Application number: GB08401131A
Authority: GB
Inventors: Paul Helderle
Original assignee: Compagnie Francaise des Petroles SA
Current assignee: Total Compagnie Francaise des Petroles SA
Priority date: 1983-01-26
Filing date: 1984-01-17
Publication date: 1984-08-15
Also published as: JPS59137692A; GB8401131D0; NO840279L; FR2539806A1

Abstract

A production-tube connection for an oil well, comprises a cylindrical outer sleeve (22) provided with an inner annular shoulder (23). A plurality of internally profiled rings (25, 29, 31, 33, 35) which are coaxial with the sleeve, are inserted into the sleeve, and are clamped axially against the shoulder to form the inner profile of the connection. <IMAGE>

Description

SPECIFICATION Production-tube connection for an oil well The present invention relates to the connections inserted in an oil-well production tube to perform certain functions, such for example as those of a receptacle, a stop means, a means of introducing a fluid laterally, protection against abrasion, etc. To perform these functions, it is necessary to have connections with a treated inner surface and/or with varied and complicated inner profiles which are difficult to produce and which are specific to the intended function. This results in high manufacturing costs and large stocks of connections kept in the vicinity of the places of use. Furthermore, the quality control of these connections is difficult to carry out, and the treatments of the inner surfaces of these connections give uneven results.

According to the invention there is provided a production-tube connection for an oil well comprising a cylindrical sleeve provided with an inner shoulder facing a first end of the sleeve, and at least one profiled ring which is coaxial with the sleeve and has a radially inner profile designed for a function to be performed by the connection and which is inserted into the sleeve and is clamped longitudinally between the shoulder and a clamping ring located on the first end of the sleeve.

Between this shoulder and the clamping ring it is possible to install a plurality of profiled rings. It is possible, in this way, to obtain complicated inner profiles in the connection by providing a longitudinal sequence of several profiled rings which are individually easy to produce. Stocking the sleeves and profiled rings separately allows desired combinations to be made as required.

Furthermore, some rings can be made of special materials befitting the working conditions of these rings.

The clamping ring can be a special ring mounted on the sleeve, but it is preferably provided by the threaded end of an adjacent production-tube element which is screwed onto the first end of the sleeve.

At least some of the profiled rings may have at their longitudinal ends means for engagement with an adjacent component formed by a ring or the shoulder.

It is possible, in this way, to avoid assembly errors and, when appropriate, prevent any possibility of rotational movement of the profiled rings.

At least one profiled ring may be provided with an O-ring seal on its radially outer periphery.

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings.

In the drawings: Figure 1 is a longitudinal half-section showing three successive conventional elements, shown spaced from one another, of a production tube; Figure 2 is a longitudinal half-section showing two successive elements of a production tube, which elements are shown spaced from one another, which includes an embodiment of a production tube connection according to the invention, and which performs the same function as the three conventional elements of Figure 1; Figure 3 is a longitudinal half-section showing two other successive elements of another embodiment of a production tube connection, which elements are shown spaced from one anqther, according to the invention; Figure 4 is a longitudinal half-section showing another assembly of profiled rings of another embodiment of a production-tube connection according to the invention; and Figure 5 shows, in perspective, a production tube connection sleeve and an assembly of profiled rings according to the invention before they are inserted in the sleeve.

The one-piece connection 1 shown in Figure 1 is provided on its radially inner surface with an anchoring recess 2, a machined upper bearing surface 3, a machined lower bearing surface 4, and an orifice 5, which is intended for the inflow of a control fluid and which passes through the connection 1, and opens in the gap between the bearing surfaces 3 and 4. This connection 1 carries in its upper part a female threaded portion 6 of the oil-well type and in its lower part a male threaded portion 7 of the oil-well type. A flow pipe 8, provided in its upper part with a female threaded portion 9 of the oil-well type and in its lower part with a male threaded portion 10 of the oil-well type, is joined to the connection 1 by mutual engagement of the threaded portions 6 and 10.Likewise, a flow pipe 1 provided in its upper part with a female threaded portion 1 2 of the oilwell type and in its lower part with a male threaded portion 1 3 of the oil-well type, is joined to the connection 1 by mutual engagement of the threaded portions 7 and 12.

In the embodiment according to the invention shown in Figure 2, the three elements 1, 8 and 11 of the production tube of Figure 1 have been replaced by two elements 14 and 1 5. The element 14 is a flow pipe similar to the pipe 8. It is provided in its upper part with a female threaded portion 1 6 of the oil-well type, like the threaded portion 9, but is provided in its lower part with a conventional cylindrical male threaded portion 1 7 and an O-ring seal 1 8.

The element 1 5 is provided in its lower part with a male threaded portion 1 9 of the oil-well type, like the threaded portion 13, and in its upper part with a conventional cylindrical female threaded portion 20 which engages with the threaded portion 1 7 to join the elements 1 4 and 1 5 together.

The element 1 5 has a thick lower cylindrical part 21 which forms a flow pipe on the inside, and a thin upper cylindrical part 22, the offset between the cylindrical parts 21 and 22 forming an annular shoulder 23. The thin upper cylindrical part 22 is provided with an orifice 24 similar to the orifice 5.

A succession of rings are installed within the cylindrical part 22. They comprise a ring 25 which has a cylindrical portion 26, the inside diameter of which is the same as that of the element 14 and a frusto-conical portion 27 which forms one of the edges of a recess 28 similar to the recess 2. The bottom of the recess 28 is provided by another ring 29. The other edge of the recess 28 is provided by a frusto-conical portion 30 of a third ring 31. Ring 31 has a cylindrical portion 32 which forms a machined bearing surface having an inside diameter a little less than that of the cylindrical portion 26. A small cylindrical ring 33 having an inside diameter greater than that of the cylindrical portion 32 has an orifice 34 communicating with the orifice 24.A fifth ring 35 which is cylindrical forms a machined bearing surface having an inside diameter a little less than that of the cylindrical portion 32. The rings 31 and 35 are provided on their outer periphery with O-ring seals 36 and 37 respectively, which ensure leak-proofing between these rings and the thin surface of the upper cylindrical part 22 of the element 15.

These profiled rings 35, 33, 31,29 and 25 are inserted into the cylindrical part 22, the ring 35 abutting the annular shoulder 23. The ring 25 is pushed by the threaded portion 17, during mutual engagement of the threaded portions 1 7 and 20, in the direction of the shoulder 23, the threaded portion 17 thus performing the function of a clamping ring for all the profiled rings.

In the embodiment of Figure 3, it is assumed that there is no need for the flow pipes consisting of the element 14 and the cylindrical part 21, thus making it possible to use shorter elements 38 and 39 which respectively replace the elements 14 and 15 of Figure 2. The same reference numerals 1 6, 1 7, 19 and 20 have been retained in this Figure 3 for the threaded portions. The element 39 comprises a short and thick cylindrical part 40 and a thin cylindrical part 41 corresponding to the thin cylindrical part 22 of Figure 2 and forming a shoulder 42 with the cylindrical part 40.

It has been assumed in the embodiment of Figure 3 that only a single machined bearing surface is needed and that no fluid inflow orifice is required. There are, therefore, a ring 25 having a lower frusto-conical portion providing one edge of a recess, a ring 29 providing the base of the recess, a ring 43 having an upper frusto-conical portion providing the other edge of the recess and a lower cylindrical portion, a ring 44 forming a machined inner cylindrical bearing surface and having an O-ring seal 45 on its outer periphery, and a spacer ring 46.

The rings 25, 29, 43 and 44 of Figure 3 are shown again in Figure 4. In this embodiment the ring 46.of Figure 3 has been replaced by an antipacking ring 47 and a spacer and stop ring 48 provided with an anti-packing groove.

Figure 5 shows the five profiled rings 25, 29, 31, 33 and 35 of Figure 2. It will be seen that these rings are provided at their longitudinal ends with projections such as 49 and recesses such as 50. This produces a mortise-and-tenon fitting system which can be different for the various rings to prevent them from being transposed during assembly. At the same time, a similar system for fitting the ring 35 relative to the shoulder 23 prevents any rotation of the rings.

Only a few exampies of profiled rings have been given,~but it will be appreciated that it is possible, as required, to use profiled rings of extremely varied configurations, and the invention specifically makes it possible to produce with a high degree of accuracy complicated connection profiles which could not be envisaged when the.

previous technique was used.

There is thus provided a production-tube connection for an oil well which is much simpler and more reliable to produce and which, since it consists of a plurality of elements, can be assembled, as required, from a stock of components, which reduces stock commitment.

Claims

1. A production-tube connection for an oil well comprising a cylindrical sleeve provided with an inner shoulder facing a first end of the sleeve, and at least one profiled ring which is coaxial with the sleeve and has a radially inner profile designed for a function to be performed by the connection and which is inserted into the sleeve and is clamped longitudinally between the shoulder and a clamping ring located on the first end of the sleeve.

2. A connection according to claim 1, wherein the clamping ring is provided by the threaded end of an adjacent production-tube element which is screwed onto the first end of the sleeve.

3. A connection according to either claim 1 or claim 2, wherein at least one profiled ring is provided with an O-ring seal on its radially outer periphery.

4. A connection according to any one of the preceding claims, comprising a plurality of profiled rings, at least some of which have at their longitudinal ends means for engagement with an adjacent component formed by another ring or the shoulder.

5. A production-tube connection substantially as herein described with reference to Figures 2 to 5 of the accompanying drawings.