One of structural elements of a well equipped with an electrical submersible pump (ESP) is wellhead assembly. It is intended to provide a positive seal around tubing string and power cable entry point into the well. The main requirement to the stuffing box for ESP wellhead penetrator is to ensure pressure integrity of inlet assembly. Leakage of production fluids and gas shall be eliminated. Stuffing box for ESP wellhead penetrator shall withstand the pressure applied by associated gases and water-oil emulsion inside the casing - tubing annulus as well as potential seasonal temperature drops. There are numerous options for sealing the ESP power cable at the wellhead. However, they all share a major disadvantage. Particularly, they all require cable stripping, which increases the risk of cable core insulation damage during installation activities, such as stuffing box packing, pumping tee installation and other operations. At subzero temperatures, the polyethylene outer sheath of power cable cores tends to crack at minor deformations. The routine practice of ESP penetrator sealing applied in TATNEFT entails unwinding the outer armor of ESP power cable, installation (packing) of stuffing box, sealing of the stuffing box by turning the sealing cap. This process is time-consuming (in fact it can take about 1 hour) and is associated with the risk of cable elements damage and premature equipment failure. In light of the above, a fundamentally new wellhead penetrator design and sealing method have been developed to eliminate the need for cable armor stripping and provide the following advantages: a) reduced penetrator installation time; b) assembly/disassembly provided by maintenance crews and operator; c) elimination of well fluid and gas leakage to the surface; d) withstanding pressures created by associated gases and water-oil emulsion during well operation; f) independence of seasonal temperature drops; e) minimized metal consumption.
