Tokaruk V. Improvement of theoretical bases and technical means for increasing the efficiency of drilling large diameter wells

The dissertation is devoted to the development of theoretical bases and technical means for increasing the efficiency of drilling large diameter wells using two rock cutting tools, namely, a bit and hole opener. To simplify the calculation of the BHA with two rock-cutting tools, a four-step technique has been developed and reduced to cyclic repetition through a certain interval. The sequence of the calculation according to the methodology is as follows: determination of the distribution of the weight on the bit and hole opener, determination of lateral forces arising as a result of the change of stressed-deformed state, determination of lateral forces that arise as a result of geological factors, calculation of the resulting lateral force, determination of the extent of eccentricity on the underreamer, determination of the curving intensity and inclination angle. A fundamentally new method of designing a well trajectory with a section of large diameter in the upper range is proposed. This technique involves the maximum use of geological distortion and the application of simplified (non-oriented) BHA. To measure the eccentricity at hole opener, a device was developed in the form of joint, which allows to determine the magnitude and direction of the eccentric displacement of the hole opener relative to the pilot hole and the inclination angle of the well in the plane of eccentricity formation.