Аңдатпа
Background: During deep drilling of oil and gas wells, the dynamic instability of the drill string caused by radial and axial vibrations of the drill bit leads to a reduction in the rate of penetration (ROP), increased tool wear, and deterioration of the wellbore gauge. This problem becomes particularly pronounced when drilling formations with alternating lithology and rock strength. An analysis of existing technical solutions, including the roller-cone reamer–stabilizer design described in the Patent of the Republic of Kazakhstan No. 22228 (E21B 10/30), has demonstratedthe need to improve the geometric and dynamic parameters of stabilizing devices intended to ensure stable dynamic equilibrium of the “bit–drill string–rock formation” system. Aim: The objective of this study is to provide theoretical and experimental justification for the causes of radial vibrations of the drilling system and to develop a near-bit roller-cone reamer–stabilizer capable of ensuring the stability of the bottom-hole assembly (BHA) at the well bottom. The stability is achieved through the efficient arrangement of the working elements at an angle of 120° and by meeting the conditions meeting the conditions for the formation of the roller cones based on their minimum size. Materials and methods: The study is based on the principles of dynamic systems theory, the laws governing energy dissipation in rotational mechanical systems, and the principle of least action. A mathematical model was developed to establish the relationship of the minimum size of the roller-cone forming elements on the nominal radius of the reamer–stabilizer. The geometric parameters of an experimental prototype of a near-bit stabilizer with a diameter of 269.9 mm, manufactured on the basis from a 203 mm heavy-weight drill pipe (HWDP), were analytically substantiated. Experimental studies were carried out under field conditions during deep drilling operations. Results: It was established that meeting the structural conditionbmin7⋅RPAC2 ensures stable dynamic equilibrium of the drilling tool relative to the wellbore axis. Field tests demonstrated a 5% increase in ROP and a 7.3% increase in bit run length. A reduction in bit balling and clogging was also observed, indicating improved hydrodynamic bottom-hole cleaning. Conclusion: The developed design of the near-bit roller-cone reamer–stabilizer validates the theoretical provisionsregarding the nature of radial vibrations in drilling dynamic systems and ensures an increase in the efficiencyof deep oil and gas well drilling. The obtained results demonstrate the feasibility of industrial implementation of the proposed technical solution and its effectiveness for application in the design of bottom-hole assembly (BHA) configurations.