This is our first well in the western part of Ukraine. The high geothermal gradient of the Transcarpathian depression (the temperature is about 165 °C at the depth of 3560 m) and the density of fluid about 1560 kg/m3 do not allow the usage of biopolymer drilling fluid. The use of clay systems, which are stabilized by acrylic polymers, is limited to the instability to the cement aggression while drilling-in cement plugs. Therefore, it was decided to provide the workover with the utilization of a special heat-resistant salt mud without solid phase. The absence of thixotropy in such liquids does not allow to keep the particles in suspension, but wellbore cleaning will be provided at the cost of high performance pumps and small depth of the well.
Artificial bottom-hole is at 1465 m depth. Productive horizons that require further exploration were identified in the process of re-interpretation of geological and geophysical data. Exploration requires drilling in through several cement bridges, where remains of drilling mud are left. Artificial bottom-hole should be restored to the depth of 3560 m. After that, the technical condition of the wellbore needs to be checked. A series of logging tests will be implemented and perforation will be performed within the interval of 3210-3551 m.
