Flexible well tool coupling

Nov. 9, 1965

3,216,751

R, W. DER MOTT

FLEXIBLE WELL TOOL COUPLING

Filed April 30, 1962

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United States Patent Office

3,216,751

Patented Nov. 9, 1965

3,216,751

FLEXIBLE WELL TOOL COUPLING Raymond W. Der Mott, Houston, Tex., assignor to

Schlumberger Well Surveying Corporation, Houston, Tex., a corporation of Texas

Filed Apr. 30, 1962, Ser. No. 190,937 3 Claims. (Cl. 285—264)

The invention relates to well tools and, more particularly, to well completion apparatus arranged for passage through small diameter strings of pipe wherein such apparatus may have considerable length and wherein the string of pipe is expected to have bends or curvatures along its length which might prohibit the passage of apparatus therethrough.

A recently developed technique in well production is the so-called multiple completion of wells wherein a plurality of strings of tubing each having relatively small diameter are cemented or otherwise disposed in a well bore. The tubing strings generally extend to different production zones and perforating of the tubing strings independently of interference with adjacent strings is desirable. In actual practice it has been found that one or more tubing strings may have a somewhat spaghettitype of configuration along the length of a bore hole which prevents or impedes the passage of elongated well tools therethrough. The incompatibility between a relatively long and rigid tool with little flexibility and the curvature or bends in long strings of tubing has presented problems which are not easily solved. For example, to further reduce the diameter of an apparatus relative to a small diameter string of tubing is generally expensive and generally introduces undesirable limitations in the apparatus. Also, in perforating devices, a reduction in diameter generally reduces operational and performance characteristics. Hence, it is generally desirable not to reduce the diameter of a tool below a maximum dimension necessary to pass through a relatively straight tubing string.

Accordingly, it is an object of the present invention to provide a new and improved elongated well tool in which sections of the tool have a cross-section sized for running clearance in a pipe string and are pivotally connected to one another along its length with provision for interconnecting the interior of the tool sections through the pivotal connection.

Another object of the present invention is to provide a new and improved jointed tool wherein a pressure sealed conduit is provided between joined sections of the tool.

Apparatus in accordance with the present invention includes a well tool having a plurality of housing sections with adjacent sections pivotally coupled to one another. The pivotal coupling for adjacent housing sections, comprises interfitting members including a spherically shaped socket portion and a spherically shaped ball portion received in the socket portion. Means are provided to retain the ball portion in the socket portion. A tube member having a relatively small diameter passes through bores in the ball and socket portions and is sealed with respect to such portions. Extension of electrical conductors and pressure balancing between adjacent housing sections is therefore possible while the housing sections are pivotally connected to one another. Means are provided to prevent rotation between the pivotal connecting portions without hindering their pivotal action.

The novel features of the present invention are set forth with particularity in the appended claims. The present invention, both as to its organization and man- ⁷θ ner of operation, together with further objects and ad2 vantages thereof, may best be understood by way of illustration and example of certain embodiments when taken in conjunction with the accompanying drawings in which:

FIG. 1 is a view of a well tool in which the present invention is embodied;

FIG. 2 is a view shown in partial cross section along the length of a coupling unit embodying the present invention and ₁₀ FIG. 3 is a view taken along line 3—3 of FIG. 2.

A well tool 10 as shown in FIG. 1, is arranged for use in a small diameter tubing string such as would be found in a multiple well completion and wherein tortuous configurations of the tubing string are expected. A 15 cable 11 is typically connected to a connector head 12 and the tool further may include a casing collar locator 13, an indexing device 14, a first radioactivity section 15, a second radioactivity section 16, and at the bottom of the tool one or more directional perforating 20 devices 17. Tool 10, in use, may be lowered into one of a number of adjacent tubing strings to a level or zone where perforation of the one tubing string is desired to provide communication between the earth formations and tubing string. At the level to be perforated, springs 25 20 on the indexing device 14 are in frictional engagement with the interior of tubing string and the indexing device 14 permits manipulation of the tool to rotate the radioactivity sections 15 and 16 as well as the perforating device 17 relative to the tubing. The radio30 activity section 15 can include means to directionally detect radioactivity relative to adjacent strings of tubing while section 16 can include a radioactivity source. Hence, with the detection of adjacent strings of tubing, the perforating gun 17 may be positioned in a selected 35 rotative position relative to the adjacent tubing strings. The foregoing, briefly described, apparatus as well as its operation techniques will not be further described herein since such description is not germane to the present invention and since such apparatus is known to 40 those skilled in the art of multiple well completion tools. Insofar as the present invention is concerned, tool 10 is made up of a number of relatively short housing sections which are joined to one another by a pivotal connection permitting pivotal movement of adjacent hous45 ing sections relative to one another and also permitting the housing sections to rotate in unison.

The pivotal connection 21, as shown more specifically in FIG. 2, includes a tubular coupling member 24 which is threadedly and sealingly received within a central bore of an exemplary housing section 15. Coupling member 24 has a cylindrical depending portion 25 terminating at a spherically shaped end portion 26. The radius of the spherical end portion has its origin at a point 27 lying on the central longitudinal axis of the ⁶⁵ member 24, the diameter of the end portion perpendicular to the central axis being greater than the diameter of cylindrical portion 25. A sub 28 is threadedly and sealingly coupled to an exemplary housing section 16. The interior of sub 28 has a bore 29 sized to receive the sphere portion 26 and an adjoining complementarity spherically shaped seal 30 upon which the end portion 26 rests. A tubular locking nut 31 is slidably received over coupling member 24 and threadedly connected to an internal thread in sub 28. The lower end ®³ of nut 31 is provided with a spherically shaped surface 32 which is complementary to the spherical curvature of end portion 26 and thus retains the sphere end portion 26 in the seat 30. A bore 33 in nut 31 extends between the spherically shaped surface 32 and an outwardly tapered surface 34. The diameter of bore 33 and tapered surface 34 are arranged to provide a

3,216,751 clearance space from the cylindrical portion 25 permitting limited pivotal movement of member 24 relative to sub 28.

To prevent rotation between member 24 and sub 28 a lengthwise extending slot 35 is provided in sphere portion 29 and a cylindrical pin 36 is mounted in sub 28 in registry with the slot. The central axis of the pin is arranged to intersect the origin point 27. The pin 36 is sized to the width of slot 35 and because pin 36 intersects origin point 27, the pivotal movement between the member 24 and sub 28 is not hindered in any way.

Coupling member 24 has a bore 37 therethrough including a bore portion 38 in which an enlarged end portion 39 of a hollow, thin-walled tube 40 is sealingly received. Sub 28 likewise has a bore 41 and a bore portion 42, the remaining end 43 of the tube 40 being sealingly received in the bore portion 42.

From the description thus far it will be seen that two housing sections 15 and 16, for example, can be connected to one another in a fluid tight relationship by the tube 40 while the interior of the tube permits the passage of conductors (not shown) therethrough without exposing the conductors to the effects of the well fluid. Also, pressure balancing of fluid in the interior of housing sections 15, 16 is possible because of the sealed tube or, alternatively the interior of the housing sections 15, 16 may be at atmospheric pressure. At the same time, the two housings can be pivoted freely relative to one another the tube 40 bending to permit the pivotal movement. Of course, the degree of pivoting desired can be preselected by appropriate proportioning of the parts forming the connection.

While a particular embodiment of the present invention has been shown and described, it is apparent that changes and modifications may be made without departing from this invention in its broader aspects and, therefore, the aim in the appended claims is to cover all such changes and modifications as fall within the true spirit and scope of this invention.