Patent Publication Number: US-11041364-B2

Title: Insert safety valve (variants)

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This is a national stage application of PCT/RU2019/000675 filed Sep. 25, 2019, which claims priority to Russian Patent Application No. 2019100186, filed Jan. 9, 2019, the contents of which are incorporated herein by reference. 
     FIELD OF THE INVENTION 
     The invention relates to oil industry and can be used for the production of oil. 
     STATE OF THE ART 
     Known is an insert safety valve [CA2586192 dated Feb. 11, 2004 or U.S. Pat. No. 7,891,428 dated 22 Feb. 2011] comprising a housing having a longitudinal bore and an annular cavity, a coupling member, a sealing element mounted within the longitudinal bore, fluid flow passages, a valve device with a sleeve. Said insert valve is mounted inside the piping safety valve available in the production tubing string and fixes it in the open state. In operation, the fluid flow passes through bypass channels which can be closed with a valve device if necessary. Opening and closing of the valve is controlled with a hydraulic line of the piping safety valve. 
     A drawback of this piping safety valve is that it requires improvements (if it is functional, but the equipment needs to be lowered on a cable, a wire, a coiled tubing, then perforation of a control line is performed, and after that the control line controls the insert safety valve) to ensure operation of the insert safety valve. 
     Further, known is an insert safety valve [U.S. Pat. No. 7,967,074, published on 28.01.11] which can be considered the closest prior art to the claimed invention. The known safety valve comprises a housing having a longitudinal bore, a landing assembly in the upper portion with extendable slips, a coupling member, fluid flow passages, valve members, a spring-driven sleeve and a landing nipple. Such safety valve can be used in case a flapper safety valve mounted in the production tubing string fails. Meanwhile, the insert safety valve is mounted within the failed piping safety valve, ensures its constantly open state, and uses its hydraulic control line. 
     A drawback of this device is a necessity to improve a safety valve present in the string and the fact that it cannot be used for its intended purpose after the insert safety valve is removed. This invention is practical to use only in case of a failure of the main (piping) valve. Due to a power source line or a rod extending within, this variant is unsuitable if activation (fixing) of the main safety valve to its closed state is required. 
     SUMMARY OF THE INVENTION 
     The object of the present invention is to provide an insert safety valve that maintains the operability of the piping safety valve mounted in the production tubing string and configured to operate electrical submersible pumps suspended on a carrying cable that extends through the interior of the piping safety valve. 
     The technical effect is achieved by providing an insert safety valve mounted within a flapper piping safety valve in a production tubing string, wherein the insert safety valve comprises a housing having a longitudinal bore, a landing nipple with extendable slips for fixing inside the piping safety valve having a landing nipple, a hydraulic line, annular seals and a valve device with a spring-driven element, the insert safety valve is lowered on a carrying cable, the hydraulic line is a tee connector coupled to two valves via tubes, the first of the valves being connected to the piping safety valve in the production tubing string, and the second of the valves extending to a slot in the inner portion of the landing nipple, wherein a hollow sleeve functions as a moving element, and the valve device is configured for aligning openings in the sleeve and the housing. 
     Furthermore, the valves on the hydraulic line are configured to open at various pressures. 
     During operation of the insert safety valve with the suggested construction in a universal production tubing (i.e., in a string having a standard piping safety valve operable without the valve of the present invention) damaging of the piping safety valve mounted inside the production tubing string is prevented since the piping safety valve can be used for its intended purpose after the insert safety valve is removed. 
     The piping safety valve can be operated in a normal mode, and if the equipment needs to be lowered on a carrying cable through the piping safety valve, the insert valve is mounted inside the landing nipple. In this case, the piping safety valve remains open throughout the mounting operation of the insert valve, and the internal space is sealed with the insert valve, if necessary. In an alternative second variant, a separate hydraulic control line extends to the insert safety valve (inside the production tubing string). In this case, each safety valve is controlled separately from the surface. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The essence of the present invention is explained with reference to the drawings, in which 
         FIG. 1  shows a longitudinal cross-section of a piping safety valve; 
         FIG. 2  shows a longitudinal cross-section of an insert safety valve; 
         FIG. 3  shows the arrangement of the insert safety valve inside the piping safety valve; 
         FIG. 4  shows the arrangement of a separate hydraulic control line. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     A piping safety valve ( FIG. 1 ) is mounted in a well-bore casing string  1  on a production tubing string  2 . A hydraulic control line  3 , which comprises a tee connector  4  with outlet tubes  5  and  6 , extends to the safety valve. A landing nipple  7  having an annular slot  8  in the inside cavity thereof is screwed onto an end of the production tubing  2 . An outlet tube  6  is connected to the inner cavity of the landing nipple  7  through a valve  9 , and the tube  5  is connected to the safety valve housing  11  fitted onto the landing nipple  7  through a valve  10 . A piston  12  is provided in the inner cavity of the housing  11 , a sliding sleeve  13  is provided under the piston with a spring  14  put on the sliding sleeve. A sealing shutter  15  in the form of a flapper is mounted in the lower part of the housing  11 . 
     The insert safety valve ( FIG. 2 ) is mounted on a carrying cable  16  and comprises a landing assembly having a locator  17  with a sleeve  18 , a spring  19  and extendable slips  20 . A sealing assembly comprising seals  21  and  22  is provided below the locator  17 , with a port  23  formed between the seals. The port  23  communicates the outside with a piston  24  mounted in the housing  25  having a longitudinal bore. The valve device comprises the piston  24  contacting with a moving element formed as a hollow sliding sleeve  26  biased with a spring  27 . The sleeve  26  has openings  28  that can either be aligned with openings  30  formed in the insert safety valve housing or be separated from the openings  30  by a seal  29 . A second seal assembly  31  is provided in the lower part of the insert safety valve on the cable  16 . 
     An alternative variant ( FIG. 4 ) differs in that a separate hydraulic line  32  configured to control opening and closing the insert safety valve independently from the piping safety valve extends along the carrying cable  16 , and the hydraulic control line  3  with the valve  10  extends directly to the housing  11 . The line  32  may extent either separately from the carrying cable  16  or inside it. When the insert safety valve is removed, the piping safety valve may be controlled with the hydraulic control line  3 . 
     The device is mounted as follows. 
     An additional landing nipple  7  is screwed on the top of the piping safety valve housing  11  (mounting instead of or in addition to the available landing nipple of the safety valve is possible). The hydraulic control line  3  is connected to the housing  11  of the piping safety valve and to the landing nipple  7  via a tee connector  4  (or directly, in the second variant). In order to open the sealing shutter  15 , a predetermined pressure is introduced into the control line  3 , wherein the pressure opens the valve  10  and shifts the piston  12 , which, in turn, shifts the sleeve  13 , which opens the shutter  15 . Herewith, in the first variant, the pressure in the line  3  should be lower than the pressure needed to open the valve  9 . If it is required to lower the assembly on a carrying cable  16  inside a piping safety valve, the insert safety valve is mounted on the carrying cable  16 , said insert safety valve includes the locator  17  mounted opposite the slot  8  while lowering. An additional collet tool is lowered inside the insert safety valve (not shown in the figures since the construction is standard and does not form a part of the insert valve), where it captures the sleeve  18  on its internal diameter and shifts it. It causes extension of the slips  20  that enter the slots  8 . After the locator  17  is installed into the slot  8 , the pressure in the control line  3  rises to the level required to open the valve  9 . After the valve  9  is opened, the fluid from the tube  6  enters the port  23 , reaches the piston  24  and shifts it. The piston  24 , in turn, shifts the sleeve  26 , thereby aligning the openings  28  with the openings  30 . When the pressure supply through the hydraulic line  3  is stopped or reduced, the spring  27  biases the sleeve  26  and the piston  24  into an upper position, which results in a seal  29  separating the openings  28  and  30 , thus isolating the insert safety valve. The fluid flow through the insert safety valve is stopped. 
     In an alternative variant, the insert safety valve is controlled via the line  32 , through which the pressure is applied to the piston  24 , and then the control is carried out as in the main variant. 
     Presented insert safety valve mounting method ensures that the piping safety valve control line is not damaged, thus, it remains operable and can be used after the insert safety valve is removed.