METHOD FOR ASSEMBLING A DRILL COLUMN FOR SECONDARY PENETRATION OF A PRODUCTIVE RESERVOIR Russian patent published in 2022 - IPC G01M7/00 G01M13/00 E21B44/00 

FIELD: well drilling.

SUBSTANCE: invention relates to the field of well drilling and can be used for their overhaul by the method of deep perforation with branched channels with ultra-small diameters and radii of curvature in sharply changing geological conditions. The method includes assembling working elements with different natural frequencies, located in a dynamically disturbed section of the loaded part of the drill string. A drill string assembly is assembled on a test bench, including oscillators, a bit, a spindle section of a downhole motor, power sections of a downhole motor, an assembly of rigid and flexible pipes with elastic-viscous mechanical characteristics and various natural frequencies, as well as a device for adjusting the axial load. Bench tests of the assembly operating modes are carried out. Measurements are carried out and the values ​​of the amplitude, vibration velocity and vibration acceleration of longitudinal, transverse and torsional vibrations of the assembly are obtained when drilling each of the rocks, trends in the total wave motions of oscillators moving with a common group velocity. The obtained values ​​are processed and the places of motion stability are determined on the test bench, the regularities of the displacement amplitudes and vibration velocity and vibration acceleration of longitudinal, transverse and torsional vibrations during drilling on the bench are determined. Spectral analysis of the results obtained is carried out by calculating the spectral densities of the working elements of the assembly, trajectories of movement of the working elements located in the dynamically disturbed section of the DSA on the phase plane are obtained. At the same time, the length of the dynamically disturbed section of the loaded part of the drill string is determined using the group velocity of energy propagation of a packet of monochrome longitudinal, transverse and torsion waves differing from each other in phase and frequency and propagating along the string with prevailing natural frequencies, with different phase velocities at linear and nonlinear, stochastic oscillations arising in the drill string due to the outputs from the resulting "motion stability nodes". Wherein an axial load regulator is additionally placed in the places of "motion stability nodes", made with the ability to operate at different damping coefficients, the prevailing natural frequency of which is obtained after statistical processing of dynamo spectral densities and phase trajectories. The required operating mode of the layout and its working elements is selected.

EFFECT: improving the trouble-free operation of the elements of the lower part of the drill string when drilling inclined and horizontal sections of long channels of small diameter and radius of curvature with a strong intermittency of drilled rocks that require a change in the drilling mode.

5 cl, 11 dwg