The Straight Hole Turbodrill

Abstract

Abstract From the first patent of a turbodrill in 1884, a span of 70 years of development and improvement was necessary before the beginning of its use as a directional drilling tool. Improvements in directional turbodrills led to the marketing of the straight-hole turbodrill and its use in problem areas of vertical wells and directional wells. Diamond bits used with turbodrills must be built with large water courses and low pressure drop across the face. Cleaning and cooling is accomplished by changes in the flow characteristics of the fluid as the rotating speed of the bit is increased. Horsepower output of a turbodrill is affected by changes in the number of turbine stages, in flow rate and in volume of fluid. A summary of drilling records shows some applications of the turbodrill. Greater drilling depths of the future will present more problems and more applications of present more problems and more applications of All down-hole motors. History of Turbodrills On Feb. 5, 1884, the U. S. Patent Office issued a patent for a turbine motor to drill wells. Patent 292,888 was issued to two brothers in the Dakota Territory, Morris and Clarence Baker, and the following is their description of the machine for operating drills (Fig. 1): "The invention consists in the application of power directly to the drill by means of a turbine or other convenient form of wheel operated by water, steam, compressed air or gas and the use of the escaped water, steam, compressed air or gas to remove the drillings from around the drill." The drawing of the Baker machine (Fig. 2) shows the turbine to have one rotor and one stator, which makes it a one-stage turbodrill. Additional patents on simple down-hole motors to be used for drilling wells were issued over the next 30 years. In the 1920's, when the principles of rotary drilling were being adapted to the drilling of oil wells, patents on improved designs of turbodrills patents on improved designs of turbodrills appeared in increased numbers. These later designs included multistage turbines, thrust bearings, improved blade design and reduction gear assemblies. None of these down-hole motors were accepted by the oilwell drillers because they did not compete economically with the conventional rotary drilling method. Bits, drill pipe, collars and drilling fluids were improved to keep up with increasing penetration rates and greater depths that were needed by the growing demand for petroleum. The only area where the turbodrill was found to be useful was in the Eastern Hemisphere, where advances in drill pipe and bits lagged and where drilling programs were not pressed by a greater and greater demand for oil pressed by a greater and greater demand for oil In the 1950's in the U.S., the turbodrill again began to appear in the oil fields for special, limited applications. Advances in technology had led to the building of a turbodrill that would have the horsepower to drill and the durability to stay on bottom. Advances in rig design and power allowed the driller to apply sufficient hydraulic horsepower to the turbodrill to make it operate successfully.