Patent ID: 12215560

DESCRIPTION OF THE INVENTION

The present invention refers to an elastomeric seal (1), made of elastic or polymeric material, which embraces the electrical conductors (5) that cross the wellhead, said seal comprises an upper cylindrical portion (11), a lower portion in a frustoconical shape (12), one to three through holes (13), which longitudinally cross the seal (1) and one to three longitudinal cuts that go from the periphery of said through holes to the seal periphery (14).

Usually, the electrical equipment used inside the well uses medium voltage electrical sources, which require the use of three-phase cable systems (6), that is, they use three phases or electrical conduction cables (5), which makes it necessary to have seals in which each electrical conductor (6) can be sealed individually or the set of two or three phases can be sealed at the same time.

In an alternative of the invention, the seal (1) comprises a through hole (13) and a longitudinal cut that goes from the periphery of one of the through holes to the seal periphery (14). Thus, the seal (1) opens longitudinally to allow the passage of the electrical conductor (5) through it and allow it to be located in the through hole (13).

In the preferred alternative of the invention, which is shown inFIG.1, the seal (1) comprises more than one through hole (13), preferably three through holes (13), a longitudinal cut that goes from the periphery of one of the through holes to the seal periphery (14) and one or two longitudinal cuts that go from the periphery of one of said through holes to the periphery of another through hole (15). In this case, the elastomeric seal (1) opens as shown inFIG.3, to allow the location of each phase or cable of the electrical conductor system in a through hole (13).

Similarly, part of the invention is the alternative in which the seal (1) comprises more than one through hole (13), preferably three through holes (13), and three longitudinal cuts that go from the periphery of one of the through holes up to the seal periphery (14), as illustrated inFIG.2, thereby allowing the location of each phase or cable of the electrical conductor system in a through hole (13).

Likewise, part of the present invention is a modular mechanical device (10) to seal conductive elements that pass through wellheads that includes the elastomeric seal (1), defined in the previous paragraphs, which is located just below a modular retaining ring system (2), whose parts are mechanically assembled, the elastomeric seal (1) together with the retaining ring (2) are located inside a seal chamber (3) and this chamber (3) fits through a threaded system with a seal chamber cover (4), as shown inFIG.3. These last two elements, the seal chamber (3) and the seal chamber cover (4), have variable external geometries that allow it to be adapted and assembled to heads of different sizes and different types of hangers (9), as can be seen inFIG.4andFIG.9.

Now, the retaining ring (2), which is shown in detail inFIG.5, is made of non-conductive material (dielectric), its external shape is cylindrical compatible with the internal seal area (31) of the seal chamber (3), comprises one to three through holes (21), through which the electrical conductors (5) pass, one to six cuts (22) that communicate the holes with the outer diameter, one to three cuts (24) that communicate the through holes (21) with each other, and one to three grooves to house the same number of seal rings (23), preferably, said seal rings or gaskets are O-rings.

For its part, the seal chamber (3), shown inFIG.6, comprises from top to bottom a first seal area (31), where the retaining ring (2) is housed, which presents on its external surface a thread system (34) and one or more housings for the ring seal (33), which is attached to the seal chamber cover (4); under the first seal area a second seal area (35) is located, where the elastomeric seal unit (1) is located; then, it has a thread system (36) on the external surface that adapts and joins the different types of pipe hanger (9); then on the same external surface it has one or several housings for seal rings (32) that seal against the pipe hanger (9), and under the second seal area (35), it has an internal passage area (37), through which the electric cable (6) or the electric conductors (5) pass.

Complementing the seal chamber (3), the device comprises a seal chamber cover (4), shown inFIG.7, which has on its outer surface one to five seats for seal rings (41), which seal against a through hole in the upper section of the wellhead (8), one or two thread systems (42,44), which adapt and assemble to one or two seal chambers (3), in the latter option, the thread (42) of the cover receives the thread (34) of a first seal chamber (3) and the thread (44) of said cover receives the thread (36) of a second seal chamber (3), and one or two seal areas (43).

In the device of the present invention, the seal chamber (3) and the seal chamber cover (4) are made of metallic material with essentially cylindrical internal and external shapes, except for the area (35) that receives the lower portion of the seal (1) and has a frustoconical shape.

Finally,FIG.8shows the typical electrical conductors (5) for electro-submersible pumps (BES), which are composed of a central conductor copper core (53) with a dielectric insulation of Ethylene Propylene Diene Type M (EPDM) (52) and a lead mechanical protection (51).

During its operation, the seal chamber (3) that joins and seals the pipe hanger (9), which houses inside it the elastomeric seal (1) being compressed towards the electrical conductor(s) (5), by means of a retaining ring (2) and the union and closure of the seal chamber cover (4) threaded in the upper part of the seal chamber (3), where the outer part of the seal chamber cover (4) joins and seals with the top of the wellhead (8).

The version of the modular mechanical device (10) to use will depend on the configuration of the wellhead. If a concentric pipe hanger (9) with three individual holes is used, where the sealing device to be used is the one that has an elastomeric seal (1) with a single through hole (13), which receives a single conductor (5), which is located so that it coincides with said hanger hole, passing a single electrical conductor (5) through each hole (13) and each device (10), making it necessary to have three devices (10), or if an eccentric pipe hanger (9) is used with a single hole where it will use a single sealing and/or repair device through which the three electrical conductors (5) will pass at the same time, which are located in three through holes (13). The latter is the most widely used embodiment of the invention and which will serve as a reference in the different Figures of the device (10).

In the same way, the device of the invention (10) can be used from one to three times in line, one above the other, joining the thread (36) of the seal chamber (3) of a second or third device with the system thread (44) of the seal chamber cover (4) of the first or second device, in order to increase the resistance to pressure, making redundant or backup barriers.

When two devices are joined, the device will comprise two chambers (3), with their respective elastomeric seals (1) and retaining rings (2), and two seal chamber covers (4), where the thread (42) of the first cover (4) receives the thread (34) of the first seal chamber (3) and the thread (44) of the first cover (4) receives the thread (36) of a second seal chamber (3), the thread (34) of the second seal chamber (3) is screwed into the thread (42) of the second cover (4) and the thread system (36) of the first seal chamber (3) is fixed to the hanger of pipe (9) located between the lower section of the wellhead (11) and the upper section of the wellhead (8), where through the use of seal rings (o-rings) it closes.

In the case where three devices are joined, the modular mechanical device (10) will comprise three chambers (3), with their respective elastomeric seals (1) and retaining rings (2), and three seal chamber covers (4), where the thread (42) of the first cover (4) receives the thread (34) of the first seal chamber (3), the thread (44) of the first cover (4) receives the thread (36) of a second seal chamber (3), the thread (34) of the second seal chamber (3) is screwed into the thread (42) of the second cover (4), the thread (44) of the second cover (4) receives the thread (36) of a third seal chamber (3), the thread (34) of the third seal chamber (3) is threaded in the thread (42) of the third cover (4), and the system of thread (36) of the first seal chamber (3) is fixed to the pipe hanger (9) located between the lower section of the wellhead (11) and the upper section of the wellhead (8), where through the use of ring seals (o-rings) it closes.

Specifically,FIG.9shows a generic and commonly used wellhead, where the electrical conductors or cables (6) coming from the bottom of the well pass through the device (10) object of the invention to be sealed inside, the device is threaded and sealed to the pipe hanger (9) located between the lower section of the wellhead (11) and the upper section of the wellhead (8), where through the use of O-rings it closes, seals and gives pressure integrity to the wellhead, allowing the cable (6) to connect with the remote external electrical source (7) maintaining hydraulic control and pressure integrity between the well and the external atmosphere.

Example 1. Operation of the Elastomeric Seal (1) and the Device (10) Containing it

In accordance with the previous description of components, we can illustrate its operation as follows:a. The device (10) is installed starting with the seal chamber (3) being screwed into the upper part of the pipe hanger (9),b. The conductor cable (6) that comes from the bottom of the well is removed from the metal shell that holds it together in the area where it is going to be sealed, in order to release and expose the electrical conductor(s) (5), then it passes through the inside of the seal chamber (3),c. The elastomeric seal (1) is opened through its cuts and the conductor or conductors (5) are introduced through the cuts (14) and (15) and are located in the through holes (13), in such a way that said seal embraces the conductors without being necessary to break the circuit, which is why the seal can be installed any length from the conductor cable (6) regardless the amount of cable before or after the seal area,d. The elastomeric seal (1) is slid into the seal area (35) inside the seal chamber (3),e. The retaining ring (2) is installed on top of the elastomeric seal (1),f. The seal chamber cover (4) is installed and threaded on the thread (34) of the seal chamber (3), the cover (4) pushes the ring (2) and compresses the elastomeric seal (1), closing the space and creating an airtight barrier seal.

The components of the device object of this invention can be placed in line or in series of two or even three complete devices one above the other, in order to increase the sealing force, generating backup barriers and thus making the system more reliable according to the requirements of the end user.

Assembled in series of one, two or three devices, the cable (6) can be connected to the external power unit (7) without requiring any type of additional connection box attached to the wellhead.