Abstract
A splice connector for a spoolable tube includes a center portion having an outer diameter equal to an outer diameter of the tube. A longitudinal extension extends in each longitudinal direction outwardly from the center portion. The longitudinal extensions have a plurality of spaced apart segments having an outer diameter equal to an inner diameter of the tube and a plurality of longitudinally spaced apart crimp grooves disposed between the spaced apart segments. An inner diameter of the splice connector is selected such that when the splice connector is assembled to the tube on each longitudinal extension, the splice connector is bendable to a radius of curvature of a winch reel used to deploy the tube into a wellbore.
Claims
1. A method for retrieving an electric submersible pump (ESP) from a well where the ESP is deployed at one end of a tubing encapsulated electrical cable (TEC), comprising: exposing a free end of the TEC extending above a surface end of the well; drilling out electrical conductors in the TEC for a longitudinal distance corresponding to a length of a first longitudinal extension of a splice connector; inserting the first longitudinal extension of the splice connector into the free end of the TEC, the splice connector having a completely solid filled, impermeable cross-section wherein the splice connector is bendable so as to be spoolable onto a winch which contains a length of the TEC, the splice connector comprising a center portion having an outer diameter equal to an outer diameter of the TEC, the splice connector comprising the first longitudinal extension extending in one direction and a second longitudinal extension extending in an opposed longitudinal direction outwardly from the center portion, the first and second longitudinal extensions each comprising a plurality of spaced apart segments having an outer diameter equal to an inner diameter of the tube and a plurality of longitudinally spaced apart crimp grooves disposed between the spaced apart segments wherein a transition between the spaced apart segments and each of the crimp grooves is square; crimping the TEC into the crimp grooves in the splice connector; and retracting the TEC with the ESP attached thereto by withdrawing the TEC and splice connector onto the winch until the ESP is disposed above a wellhead at an upper end of the well.
2. The method of claim 1 further comprising reinserting the ESP into the well to a depth enabling a selected length of the TEC to extend above the wellhead; securing the TEC longitudinally in the wellhead; and exposing the electrical conductors in the extended TEC to make electrical connection to the ESP in the well.
3. The method of claim 2 wherein a spacer is connected between the end of the TEC and the ESP, the spacer having a length selected to adjust for a length of the TEC removed during the retrieval of the ESP from the well.
4. The method of claim 1, wherein the crimping comprises making a first crimp at each crimping groove followed by a second crimp at each crimp groove rotated 90 degrees from the first crimp.
5. The method of claim 4 wherein the splice connector is formed from at least one of titanium and alloys thereof.
6. The method of claim 1, further comprising closing a valve in the wellhead; and retrieving the ESP from a lubricator coupled to the wellhead.
7. The method of claim 1, wherein the crimp grooves comprise an outer diameter smaller than the outer diameter of the segments by an amount equal to a wall thickness of the TEC.
8. The method of claim 1 wherein the splice connector is pre-assembled to the length of the TEC disposed on the winch.
Description
BRIEF DESCRIPTION
(1) FIG. 1 shows an example of a splice connector to mechanically join two ends of a tubing encapsulated cable (TEC) or other tube.
(2) FIG. 2 shows the splice connector of FIG. 1 assembled to two ends of a TEC.
(3) FIG. 3 shows the splice connector attached to an end of a TEC spooled on a winch.
(4) FIG. 4 shows the upper end of a cut to length TEC as it may protrude from a well head.
(5) FIG. 5 shows the splice connector being inserted into a prepared end of the TEC protruding from the well head.
(6) FIG. 6 shows the same view as FIG. 5 with mode detail as to a safe working area below a “lubricator” conduit.
(7) FIG. 7 shows using a crimping tool to attach the splice connector to the well head end of the TEC.
(8) FIG. 8 shows a completed splice.
(9) FIG. 9 shows the spoolable splice connector disposed on a winch reel as the TEC is withdrawn from the well.
(10) FIG. 10 shows an example deployment of an ESP on the end of a TEC.
DETAILED DESCRIPTION
(11) FIG. 1 shows an example of a spoolable splice connector 10. The spoolable splice connector 10 may comprise a centrally disposed “full diameter” section 10A which has an outer diameter substantially the same as a tubing encapsulated cable (TEC, see FIG. 2) or other tube to be spliced together. A plurality of crimp grooves 10B may be disposed on longitudinal extensions 10C extending from each longitudinal end of the full diameter section 10A. The crimp grooves 10B are disposed between longitudinal segments 10D on each longitudinal extension 10C. The longitudinal segments 10D may have an outer diameter approximately the same as an internal diameter of the TEC or tube to be spliced. The crimp grooves 10B may have a depth approximately equal to the wall thickness of the TEC or other tube to be spliced. An outer diameter of the splice connector 10 may be selected such that when the splice connector 10 is assembled to two separated ends of a tube such as the jacket of a TEC, the splice connector 10 and the assembled TEC or tube ends (see 12A, 12B in FIG. 2) have a substantially constant outer diameter over the entire length of the splice. Such outer diameter may be substantially the same as the nominal outer diameter of the tube or TEC. An inner diameter of the splice connector may be selected such that when the splice connector is assembled to the tube on each longitudinal extension, the splice connector and the tube are bendable to a radius of curvature of a winch reel (see FIG. 9) used to deploy the tube in a wellbore.
(12) In some examples, the edges of the crimp grooves 10B may have sharp (very small radius) edges to ensure sufficient axial load strength to the assembled crimp connector 10 and tube ends. In some examples, the spoolable splice connector 10 may be made from a high strength, ductile (and therefore bendable) material such as titanium and alloys thereof.
(13) FIG. 2 shows an example of a splice connector 10 having its two longitudinal extensions 10C in FIG. 1 disposed in open ends 12A, 12B of a TEC or other tube to be spliced together. Example longitudinal positions for crimping the tube at its separate longitudinal ends 12A and 12B are shown at 14A, 14B, and 14C.
(14) In some examples, a service vehicle or other supporting platform having a winch thereon may have spoolable TEC or other spoolable tube (e.g., coiled tubing) on the winch prior to commencement of ESP retrieval operations. FIG. 3 shows an example of a splice connector 10 already crimped onto a free end of a TEC or tube extending from a winch (see FIG. 9). One of the longitudinal extensions (10C in FIG. 1) is already disposed inside the end 12A of the tubing or TEC substantially as shown in FIG. 2. The other longitudinal extension 10C of the splice connector 10 is exposed, showing the longitudinal segments 10D and crimp grooves 10B substantially as explained with reference to FIG. 1.
(15) FIG. 4 shows the other end 12B (e.g., the end of the TEC protruding from the well head) or other tube to be spliced by coupling to the splice connector (10 in FIG. 3). The other end 12B in the present example is an end of a TEC and comprises electrical conductors 12C, a longitudinal portion of which will be removed prior to splicing the other end 12B to the splice connector (10 in FIG. 3). Removing the longitudinal portion of the electrical conductors 12C in a TEC may be performed using a drill or similar tool. In some examples, the drill may comprise a bit having a hardness sufficient to cut through copper or aluminum electrical conductors and plastic or other insulation surrounding the electrical conductors 12C but not sufficiently hard to readily drill through the encapsulating tube 12D. In some examples, the length of the electrical conductors to be removed is approximately the same as the length of the longitudinal extension (10C in FIG. 3) of the splice connector 10.
(16) FIG. 5 shows the splice connector 10 inserted into the free end 12B of the TEC protruding from the well head after the electrical conductors have been drilled out and the interior surface of the TEC has been smoothed, such as by deburring or honing. FIG. 6 shows the same view as FIG. 5 with more detail as to a safe working 22 area below a “lubricator” conduit 20 that has been raised above the well head (not shown in FIG. 6).
(17) FIG. 7 shows using an hydraulic crimping tool 24 to crimp the tube end 12B into the crimp grooves (10B in FIG. 1) on the longitudinal extension (10C in FIG. 2) of the splice connector 10. In the present example, a full circumference crimp is not required. In some examples, a crimp pattern may be arranged such that for each crimp groove (10B in FIG. 1), a first crimp is made in the tube or TEC end 12B, followed by a second crimp made in the same crimp groove (10B in FIG. 1) oriented 90 degrees rotated with respect to the previous crimp in that same crimp groove. Thus, in the example of the splice connector shown in FIG. 1, in which there are three crimp grooves (10B in FIG. 1) on each longitudinal extension (10C in FIG. 1), a total of twelve individual crimps may be made in the TEC tube or other tube. In some examples, the crimp procedure may begin at the longitudinally most distant crimp groove (10B in FIG. 1) from the full diameter section (10A in FIG. 1) successively inwardly toward the full diameter section (10A in FIG. 1) to yield tube material up against the shoulder of the full diameter section (10A in FIG. 1).
(18) FIG. 8 shows the finished splice connection suspended above the well head. The completed splice includes the end of the tube 12A disposed on the winch (FIG. 9), the splice connector 10 and the well end of the tube 12B coupled together to form a splice having a substantially constant outer diameter along the entire length of the splice.
(19) FIG. 9 shows the splice connector 10 after the winch 30 has been operated to retract some of the TEC from the well. During ESP retrieval operations, the winch 30 may be operated to retract the TEC or tube from the well until the ESP is fully withdrawn from the well.
(20) A tubing encapsulated cable (mechanical) splice according to the present disclosure can withstand repeated plastic bending deformation cycles without low cycle fatigue failure within the required service life of the TEC, which includes bending around two sheaves and one winch reel (see 30 in FIG. 9) for retrieval of the ESP system back to surface. The splice connection 10 can retain the full tensile strength of unspliced portions of the TEC or other tube. The outer diameter of the completed splice is smooth and is substantially the same as the TEC or other tube.
(21) The splice connector features sharp edged grooves to “bite” into the TEC or other tube. In some examples, reuse of cable, for example, TEC, that has been cut/terminated/spliced for retrieval as explained above may be facilitated by use of a spacer bar inserted into the ESP equivalent in length to the length of cable (e.g., TEC) cut out at surface during the above-described re-termination process. A TEC splicing system as described herein may work in combination with a modified rod lock blowout preventer (BOP) system for gripping and sealing on the cable at the wellhead.
(22) FIG. 10 shows an elevational view of an example of an ESP 40 attached to a tube 12 such as a TEC. The ESP 40 and tube 12 are disposed in a wellbore W which is drilled through subsurface formations for the production of fluids such as water and/or petroleum. The ESP 40 may comprise a motor M, a shroud S, a gearbox and drivetrain assembly G and a pump P such as a centrifugal pump. The ESP 40 may be retained in place in the wellbore W and sealed using an annular seal 42 such as a packer positioned in a wellbore casing C at a selected depth in the wellbore W.
(23) As used herein, the term “petroleum” refers broadly to all mineral hydrocarbons, such as crude oil, gas and combinations of oil and gas. The tube 12 connects the electric submersible pumping system 40 to a well head WH located at the surface.
(24) Fluid emerging from the wellbore W may pass through a “wing” valve WV forming part of the wellhead WH and thence delivered to suitable produced fluid processing equipment (not shown). To close the well, a master valve MV may be included in the well head WH. Although the electric submersible pumping system 40 is designed to pump petroleum products, it will be understood that the present example of a pumping system can also be used to move other fluids, for example and without limitation, water.
(25) The motor M may be an electric motor that receives power from a surface-mounted motor control unit MC through the TEC 12. When energized by the motor control unit MC, the motor M drives the pump P.
(26) An example of a splice installation and ESP removal procedure may include the following: a) open well barriers, e.g., valves such as master valve MV; b) strip back connections to bare cable (TEC) 12 and conductors (12C in FIG. 4) c) drill out conductors (12C in FIG. 4) within the TEC 12 to a selected length; d) de burr ID and OD of the TEC tube; e) shoulder the splice connector (10 in FIG. 1) to the edge of the drilled out TEC (12B in FIG. 4), and mark crimping positions; f) push the splice connector (10 in FIG. 1) into the end of the TEC tube (12B in FIG. 4); g) use an hydraulic crimping tool (24 in FIG. 7) to crimp in first position (outer, see 14C in FIG. 2), rotate the hydraulic crimping tool 90 degrees and crimp once again in the same crimp position; h) repeat crimp procedure in (g) at the second position (middle, see 14B in FIG. 2); i) repeat crimp procedure in (g) in the third position (inner, see 14A in FIG. 2); k) close the well such as by operating master valve MV; l) pull test the splice connection such as by rotating the winch (30 in FIG. 9); m) release a cable wellhead gripper (not shown); n) begin pulling the TEC with ESP system attached upward, pulling the splice connector (10 in FIG. 1) through the packing glands on the lubricator (20 in FIG. 6), over sheaves, and back to the winch reel (30 in FIG. 9); o) retrieve the ESP 40 to surface by continuing to spool TEC onto the winch reel (30 in FIG. 9) over the top of the spoolable splice connector; p) close well such as by operating master valve MV, open the lubricator (20 in FIG. 6).
(27) Reinstallation of the ESP 40 may be performed by reversing the above procedure and removing the splice connector (10 in FIG. 1) from the exposed end of the TEC after the ESP 40 is fully disposed in the wellbore W.
(28) Possible benefits of a method and system as described herein may include, without limitation, enabling retrieving an ESP pump system under live well conditions (avoid killing the well with fluid) pulling cable under combined tension and bending through a dynamic seal (pack off) and around sheave wheels back to the winch.
(29) Although only a few examples have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the examples. Accordingly, all such modifications are intended to be included within the scope of this disclosure as defined in the following claims.
