OREANDA-NEWS. September 20, 2011. Experts of TatNIPIneft have developed special technologies for the purpose of improving the efficiency of drilling wells in the fields of TATNEFT, reported the press-centre of TATNEFT.

One of them is a whipstock (Russian Federation Patent No. 2366793) intended for sidetracking in the process of idle and low-margin wells recovery. Unlike other analogues the whipstock of TatNIPIneft is fixed in the production string by an anchor made of an expandable pipe. The anchor is capable of withstanding axial load of 200 kN and torque of 10.8 kNm, which prevents displacement of the whipstock when cutting a window and drilling a sidetrack. Unlike the whipstock secured by mechanical rams or cement slurry, the whipstock of TatNIPIneft has an arrangement in the design allowing to press the whipstock against the wall of the production casing with a force of up to 15 kN making it possible to cut a window and drill a sidetrack in the direction opposite to the trajectory of the main wellbore.

Application of this technology allows reducing the well workover time through drilling a sidetrack by 4 days, or reduces the cost of drilling a sidetrack by 520 thousand rubles

Also the experts of TatNIPIneft have developed a technology of cementless casing of sidetracks with application of profiled liners to provide for effective sidetracking (Russian Federation patent No. 2365728). This method reduces the cost per well up to 300 thousand rubles and it is successfully applied to isolate lost circulation zones, as well as zones of rock debris and caving in four wells of TATNEFT.

Currently, the scientists of TatNIPIneft are engaged with improving the technology: they plan to use expandable liners for drilling problematic areas without reducing the diameter of the sidetrack.