TABLE OF CONTENTS The issue of using turbodrills to drill directional wells was put forth in 1939 and 1940 with the introduction of the T-6, T-10, and T-14-9 3/4-in. functional multistage turbodrills and the application of turbodrilling methods when drilling deep commercial wells in the Baku region and the Ishimbai region of Bashkiria. In those years, drillers primarily used the American directional drilling technology that combined rotary drilling with whipstocks, spring and hinged deflectors, and other tools. In the 1930s, this technology was used to drill wells in the Starogroznensky area in Grozny and the Artem Island in Baku.
The technology featured a number of serious drawbacks and resulted in a significant slowdown in the directional well drilling process, numerous cases of drillpipe failures, and poor quality (step-shaped) well boreholes. Removable whipstocks were widely used by drillers, which required a number of additional trips for setting the whipstock, drilling a short section using a small diameter bit, pulling out the whipstock, and running in special reamers to ream the inclined section that was drilled. In addition, application of a removable whipstock was possible only in soft- to medium-hardness rock. Directional wells had never been drilled in the hard rock (Paleozoic age) that was predominant in the Urals-Volga oil provinces.
Running a DHM in combination with an elastic deflector for directional drilling applications achieved a simpler way to control borehole inclination buildup...
