LLP Scientific Innovation Center Almas, Almaty, Kazakhstan:

Mendebaev T. N., Chief Researcher, Doctor of Engineering Sciences
Smashov N. Zh., Chief Executive Officer, Candidate of Engineering Sciences

Al-Farabi Kazakh National University, Almaty, Kazakhstan:
Kuatova M. Zh., Post-Graduate Student, kuatova.moldyr@gmail.com

The key problems in deep drilling are preservation of the preset well direction, reduction of energy consumption, production of high-quality geological material in the form of core and improvement of rock-breaking tool performance. This paper reviews the research works aimed at solving these problems. These studies mainly deal with design features, implementation and working conditions of diamond drill bits which are the most popular in well drilling. It is found that well deflection depends on the method of drilling, on the shape of the diamond bit matrix and on the axial load applied to it. The practice proves that stead-state path of well drilling is possible with making annular channels on the bottom face of the tool matrix. The use of potential energy of fluids to break rocks is one of the ways of solving the deep well drilling problems, which is highlighted in some of the research works. The most promising facilities are the bottom-hole assembly with hydraulic control valve and thin-walled diamond bits, hydraulic units with renewable bottom-hole energy source and rock destruction by water jets. The novelty of the latter approach is presented in the structural diagram of the diamond tools consisting of a matrix with annular channels on the bottom face divided into sectors by flushing slots, and with axial holes coming to the annular channels. The flushing slots have partitions, the bottom and sidewalls of the annular channels have parallel grooves extending to the flushing slots oppositely to the tool rotation. This structural layout ensures separate flush fluid feed and mud removal, volumetric destruction of rocks by fluid jets and cooling of the tool. The industrial tests of the prototype diamond tools show that they offer higher well drilling efficiency as against the series-produced HQ type bits.

The study was supported by the Committee of Sciences of the Ministry of Education and Science of the Republic of Kazakhstan, Grant Financing Agreement No. 106 as of March 5, 2018.

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