Abstract
Currently, the main part of oil in Russia and in the world is produced from low- and average-flow-rate wells. Comparing to high-yield well stock, artificial-lift production from these wells has its own complications associated with increased overheating of equipment, with more intensive process of salt and paraffin-asphalt deposition. This leads to the necessity of frequent round-trips and, as a consequence, well killing. As a result the costs and time for workover increase; also while killing low-flow-rate oil wells, filtration characteristics of the borehole zone are getting much worse. In addition, the technology of artificial-lift operation, based on pumping the liquid from the bottom to the surface, is becoming more promising for the flooded gas and gas-condensate well operation. Typically, these wells are operated at a late stage in a high water content and low reservoir pressure, when well killing is also related to a risk of significant gas productivity decline.
In this regard, we developed a new artificial-lift technology without well killing. A distinctive feature of the technology is the use of umbilical, which is made as one segment on the basis of steel-polymer pipe. Umbilical includes both hydraulic channels for the fluid flow and electrical conductors of different cross sections for the power of ESP that allows you to replace the commonly used steel tubing with an external installation of the power cable. Wellhead BOP provides the possibility of workover without well killing.
Bench tests of umbilical with a suspended ESP were successful and they confirmed the operability of the technology. Umbilical itself is favorably different from tubing as it reduces the probability of damage of the power conductors and leaks occurrence, reduces hydraulic friction losses, heat losses, physical and chemical inertness.
Thus, this technology reduces the time and maintenance costs of workover, increases the security of round-trips, and also increases the efficiency of artificial lift operation of oil and gas wells.
