US3340932A

US3340932A - Sub-surface connector for plural tubing elements

Info

Publication number: US3340932A
Application number: US449824A
Authority: US
Inventors: Peter S Bloudoff
Original assignee: Armco Inc
Current assignee: Armco Inc
Priority date: 1965-04-21
Filing date: 1965-04-21
Publication date: 1967-09-12
Anticipated expiration: 1984-09-12

Description

Sept. 12, 1967 P. S. BLOUDOFF UB-SURFACE CONNECTOR FQR PLURAL TUBING ELEMENTS Filed April 21. 1965 Ens m I ll???" l I v v 3 5 l h may I. ll Y Fiat?! ul 3 q P. a 6 R m y 7 O 7 8 3 3 .M m m T E w m m 255M 5 ,5. q mmmmmm m I 5 l R E T m E Y P B Y United States Patent 3,340,932 SUB-SURFACE CONNECTOR FOR PLURAL TUBING ELEMENTS Peter S. Bloudotf, Whittier, Calif., assignor to Armco Steel Corporation, Middletown, Ohio, a corporation of Ohio Filed Apr. 21, 1965, Ser. No. 449,824 6 Claims. (Cl. 166-243) ABSTRACT OF THE DISCLOSURE This invention relates to a sub-surface connector assembly for oil wells or the like in which a plurality of separate strings of tubing extend from the surface to a downwell pumping system.

There are many instances in which present practices relating to the recovery of oil dictate the use of a plurality of separate strings of tubing run side by side in the oil well casing. Pumping from dual producing zones and pumping by hydraulically actuated downwell pumps are the most frequent. Because in this instance one or more of the tubing strings will convey fluid at very high pressure, the hydraulically actuated downwell pumping case is, perhaps, the most demanding.

At the present time, fluid actuated downwell pumps are frequently used as free pumps; that is, the unit is seated in a prepared cavity at the production zone without any mechanical connection to the surface. The cavity in which the pump is seated during operation comprises a number of precisely located and related cylindrical elements having ports for the introduction of power oil at high pressure, for the removal of spent power oil, and for the removal of produced oil. The prepared cavity is adapted to receive a movable assembly of tubing and packing elements that are related to each other both radially and longitudinally in such a manner that when seated in the cavity the necessary separate connections to the several tubing strings are established. This assembly is prepared at the surface and is lowered into the cavity. In those instances where two or more separate strings of tubing extend from the sub-surface. assembly to the surface, it is advantageous and customary to run a primary tubing into the well along with all of the elements that make up the lower cavity assembly and carrying a landing collar to which these cavity elements are attached. After the primary tubing and the cavity assembly are run and seated in the well, the separate side string or strings are run in and are connected to the landing collar in which a coupling is established between the cavity assembly elements and the side strings. In many instances, attempts have been made to latch the side strings in place in the landing collar, but these attempts have given mechanical trouble particularly when for some reason it became necessary to remove all for some of the tubing strings for the well.

Where it has been attempted to establish a hydraulic seal between the side strings and the conduits extending into the landing collar, it has been found difiioult to lower the sealing elements into the well without dam- Patented Sept. 12, 1967 aging them to the extent that they would fail to function against the relatively high hydraulic pressures that prevail. The damage has been due largely to the abrasive action of the casing joints that the seals pass in their trip from the surface to the landing collar.

The present invention has for its primary object to overcome the disadvantages of the prior art and to provide a sub-surface connector that will enable the precise adjustment of the elements of a cavity assembly prior to its insertion into a well and will thereafter accept, locate, and seal the connectors carried by the subsequently lowered side strings.

Another object of the invention is to provide a sealing arrangement for a subsequently inserted side string in which only internal, and thus protected, seals are used.

Other objects and advantages of the invention will become apparent from the following detailed description of a prefered embodiment thereof, reference being had to the accompanying drawings, in which:

FIG. 1 is a perspective view, with parts broken away, and parts in section, of a sub-surface assembly embodying the present invention;

FIG. 2 is a section on line 22 of FIG. 1;

FIG. 3 is a section on line 33 of FIG. 1; and

FIG. 4 is a central, vertical, sectional view of a protected seal element.

Referring to the drawings and particularly to FIG. 1, the present invention is shown as a part of a sub-surface assembly in which connections and seals are made to three separate strings of tubing that, when installed, will extend from the cavity to the surface. The tubing strings as shown comprise a primary string 10 and parallel side strings 11 and 12. The primary string 10 may be of a diameter to accept a standard downwell pump, to be operated as a free pump.

The

tubing strings

10, 11 and 12 may be considered as terminating in a landing collar 13. Below the landing collar there are conduits and conductors that correspond to the several tubing strings, but that form a part of a prepared cavity that cooperates with the stationary elements of a movable assembly whether the stationary elements comprise parts of a dual zone pumping system or parts of a fluid actuated downwell pumping system. The primary tubing string 10 is threaded into the landing collar 13 by straight threads, in a known manner, and a cavity extension tubing of corresponding diameter is inserted in the opposite side of the collar as is conventional. These threads are not shown in the drawing, since they are commonly used, although the cavity extension tube is designated 10a in FIG. 1.

The landing collar 13 is also provided with

side passages

15 and 16 that are conically enlarged at the upper end to form respective guide recesses or sockets 17 and 18. At the lower end the

passages

15 and 16 are threaded at 19, 19a to receive

landing stern adapters

20 and 21. Since the assemblies associated with each of the

passages

15 and 16 are similar, only one will be described in detail and the parts thereof shown in FIG. 2.

In addition to being threaded at its upper end for insertion into the landing collar 13, the landing stern adapter is internally threaded at the lower end to adjustably receive a landing stem 22.

The landing stem 22 comprises a tubular body adapted to receive a conductor pipe 24 at its lower end in a threaded or other joint 25. Due to manufacturing tolerances, the length of the conductor pipe may vary somewhat so provision is made for longitudinal adjustment in the connection of the landing stem to the adapter 20 and thus to the landing collar 13. As above noted, the connection between the two. parts is preferably made by threads on the adapter and a long series of threads 26 on the landing stem 22. A lower locknut 27 is first placed over the threads 26 and an upper locknut 28 is threaded over the upper portion of the same threads, and will bear against a shoulder 29 within the landing stem adapter when the parts are finally located in the proper longitudinal relationship. By using the

opposing locknuts

27 and 28 against the external and internal surfaces respectively of the landing stem adapter, adjustment of the landing stem will be preserved While the assembly is lowered into the well. A tack weld between the landing stem 22 and the conductor pipe 24 can also be used to maintain the adjusted position of the parts.

At its upper end the landing stem 22 is formed with a spear or pin extension 30 having a smooth exterior and a tapered upper extremity. The ultimate seal for the subsequently lowered side string is made against the exterior of the spear or pin extension 30.

The landing stem adapter 20 is provided with a peripheral series of milled slots 31 to assure the passage and expulsion of trash or dislodged foreign matter that may enter the space around the landing stem during the running of the side strings. The foreign matter is thus prevented from lodging against the sealing surface of the pin 30.

Each side tubing string 11 and 12 carries a similar seal and packing assembly at its lower end, so that it will be necessary to describe only one, as shownin FIG. 2.

A landing spear housing 33 is attached to the tubing string 11 by a coupling 34, and carries a friction ring 35 on its outer periphery just below the coupling. The friction ring 35 is preferably formed of brass or a metal having a similar modulus of elasticity and similar anti-galling characteristics. The landing spear housing 33 has an' enlargement in the inner diameter at 36 to receive a series of packing rings 37 that are held in place by a guide nose 38 threaded into the lower end of the housing 33. The packing rings 37 are preferably of the reverse chevron type for most effective sealing and are dimensioned for a close packing fit around the smooth exterior of the spear or pin 30. The internal diameter of the tubing string 11 and the landing spear housing 33 is purposely made slightly larger than the bore of the conductor pipe 24 and the bore of the landing stem. In this way, high pressure Within the side string 11 will exert a hydraulic downward force on the packing rings 37 tending to hold the spear firmly in place around the pin 30. Thus the pressure within the tubing will not act in a direction tending to blow the tubing ofi? its seat in the landing collar.

All of the parts below and attached to the landing collar 13 are assembled on the surface, with the proper longitudinal adjustment of the conductor pipes being made prior to tightening the upper and

lower locknuts

27 and 28. When these parts are properly assembled, they are lowered into the well by attachment to the primary tubing until they are properly located in the well casing.

When the parts are located in the casing of the Well, one of the side strings 11 or 12 is run in until the guide nose 38 enters the flared socket 17 in the landing collar 13. Inasmuch as there may be several thousand feet of the small tubing made up at this time, it is not possible for the operator at the surface to know which of the two or more conical socket surfaces of the landing collar has been engaged by the guide nose 38. He knows only that the parts have landed on the landing collar. The operator next elevates the entire side string by a foot or eighteen inches and then makes up and runs the second side string, placing it properly in the right or left side of the casing as indicated in FIG. 3. There is not enough room in the casing for the small tubing strings to cross each other so that the second tubing is necessarily run down the proper side of the well and the first tubing is forced to overlie its proper socket in the landing collar. The second tubing string may be run and fully seated while the first string is still elevated.

Seating of the tubing string comprises entry of the guide nose 38 over the tapered upper end of the pin extension 30. This entry continues until the guide nose seats against the lower end of the pin extension at which time the packing rings 37 will completely surround the pin or spear extension 30. The friction ring 35 engages the bore in the landing collar at this time. It is possible to tell from the surface whether the parts are properly seated because the increased friction imparted by the ring 35 will make elevation of the string somewhat more difficult than the similar raising of the previously lowered string which is still elevated somewhat above the landing collar. It will be noted that the friction ring 35 is not called upon to perform any sealing function but merely to serve as an indicator to the operator at the surface that the parts are, in fact, in their desired location.

Once the second side string has been properly located and sealed, the previously elevated companion string may then be lowered fully into place, again using the friction ring 35 to indicate whether or not a full seating has been obtained. Since the mass of the ring 35, the area of its contacting face, the coefficient of friction, and other parameters are known, the configuration of a proper friction ring can be calculated to give a highly consistent interference fit between the seated parts.

It will be noted that the packing rings 37, upon which reliance is placed to prevent loss of pressure of fluid in the side string, are fully protected by the guide nose 38 and by the housing 33 during the entire time that the assembly is being lowered into the well. These parts cannot become damaged by the abrasive action of the casing joints that they necessarily pass during their entry operation. Any foreign matter that is dislodged by the guide nose 38 or the coupling 34 or by the remainder of the tubing string that is run into the well will pass out of the system through the milled slots 31 in the landing stem adapter and will not lodge in any position in which they may prevent the proper seating of the parts.

It will be seen that the present invention provides an arrangement whereby certain of the parts may be conveniently assembled at the surface with a precise adjustment and that thereafter the side strings may be run into the well and positively sealed with respect to the previously lowered movable well assembly element.

While the invention has been described in conjunction witha specific form and disposition of the parts, it should be understood that numerous modifications and changes may be made without departing from the scope of the appended claims. The disclosure has been made in conjunction with a primary tubing and two side strings, but it is equally adapted to one or more side string assemblies as will be readily apparent.

What I claim is:

1. In a sub-surface connector having a plurality of tubing elements extending downwardly therefrom when located in a well casing and constructed and arranged to receive a plurality of tubing strings extending from the surface, one of said tubing elements acting as a primary tubing, a landing collar supported initially by said primary tubing, adapter means forming a separate and adjustable threaded connection between said landing collar and at least one other of said downwardly extending tubular elements, said adjustable threaded connection comprising upper and lower locknuts engaging a portion of said adapter means, said landing collar having a downwardly tapering recess overlying at least one of said tubing elements adapted to guide into a predetermined location a subsequently lowered tubing string, and means carried within said recess to form a packing connection between said subsequently lowered tubing string and one of said downwardly extending tubing elements.

2. In a sub-surface connector having a plurality of tubing elements extending downwardly therefrom when located in a well casing, the improvement comprising a landing collar having separate threaded means operatively connected to each of said tubing elements, said threaded means including a landing stem having a packing pin extending into said landing collar, said landing collar having a downwardly tapering recess overlying and surrounding said packing pin and adapted to guide a subsequently lowered tubing string into a predetermined position, and packing members carried internally of said subsequently lowered tubing string cooperating with the exterior of said packing pin to form a fluid tight connection therewith.

3. In a sub-surface connector having a plurality of tubing elements extending downwardly therefrom when located in a well cavity, the improvement comprising a landing collar having separate means operatively connected to each of said tubing elements, said means including a landing stem having a packing pin extending into said landing collar, said landing collar having a downwardly tapering recess overlying and surrounding said packing pin and adapted to guide a subsequently lowered tubing string into a predetermined position, and packing members carried internally of said subsequently lowered tubing string cooperating with the exterior of said packing pin to form a fluid tight connection therewith.

4. The improvement defined in claim 3 in which the effective internal diameter of said subsequently lowered tubing string is large enough to create a hydraulic force tending to move said packing members over said packing pin in a sealing direction.

5. The improvement defined in claim 3 in which said subsequently lowered tubing string carries a friction ring engageable with a wall of said landing collar recess to resist displacement of said subsequently lowered tubing string from its landed position in said landing collar.

6. In a sub-surface connector having a plurality of tubing elements extending downwardly therefrom when located in a well casing, the improvement comprising a landing collar, an adapter between said landing collar and at least one of said tubing elements, a landing stem threaded into, said adapter, said adapter having at least one peripheral recess for the disposal of foreign matter from around said landing stern, said landing stern having a packing pin extending upwardly into said landing collar recess, said landing collar having a downwardly tapering recess overlying and surrounding said packing pin and adapted to guide a subsequently lowered tubing string into a predetermined position, and means carried within said recess to form a packing connection between said subsequently lowered tubing string and the exterior of said packing pin.

References Cited UNITED STATES PATENTS 171,615 12/1875 Hardison 166-189 X 2,488,931 11/1949 Penick 166-45 2,976,934 3/1961 Todee 166243 2,999,544 9/1961 Conrad et a1 166134 3,083,768 4/1963 Althouse et a1. 166189 X 3,098,524 7/1963 Brown 166-52 CHARLES E. OCONNELL, Primary Examiner.

I. A. CALVERT, Assistant Examiner.

Claims

3. IN A SUB-SURFACE CONNECTOR HAVING A PLURALITY OF TUBING ELEMENTS EXTENDING DOWNWARDLY THEREFROM WHEN LOCATED IN A WELL CAVITY, THE IMPROVEMENT COMPRISING A LANDING COLLAR HAVING SEPARATE MEANS OPERATIVELY CONNECTED TO EACH OF SAID TUBING ELEMENTS, SAID MEANS INCLUDING A LANDING STEM HAVING A PACKING PIN EXTENDING INTO SAID LANDING COLLAR, SAID LANDING COLLAR HAIVNG A DOWNWARDLY TAPERING RECESS OVERLYING AND SURROUNDING SAID PACKING PIN AND ADAPTED TO GUIDE A SUBSEQUENTLY LOWERED TUBING STRING INTO A PREDETERMINED POSITION, AND PACKING MEMBERS CARRIED INTERNALLY OF SAID SUBSEQUENTLY LOWERED TUBING STRING COOPERATING WITH THE EXTERIOR OF SAID PACKING PIN TO FORM A FLUID TIGHT CONNECTION THEREWITH.