HYDRO-MECHANICAL DRILLING OF WELLS

Abstract

The solution to the problems of the construction of deep wells is possible when creating downhole tools on a fundamentally new ideological basis, involving physical principles, technical solutions unconventional in the field of drilling equipment. It is important to take into account the energy resources that increase with depth. Following this concept, based on the tasks of geological exploration, a downhole layout has been developed and introduced into the production of drilling wells, with design features and technological capabilities focused on a comprehensive solution to the problems of well wiring. Structurally, the downhole layout aimed at maximizing the potential energy of the working fluid is universal, designed for drilling wells with core sampling of increased diameter (100 mm or more), and with a solid face. In addition to the outer pipe and core receiver, the downhole layout is equipped with diamond drill heads with a stepped matrix, with a separate system of flushing channels, collectively realizing the effect of hydro-mechanical destruction of rocks. By introducing into the composition of the bottom-hole layout, converting the ascending flow into a rotational-ascending one, the problem of removing sludge from under the end of the stepped matrix is effectively solved. Production tests of the downhole layout with core sampling were carried out at the polymetals deposit of Central Kazakhstan, solid face during drilling of groundwater wells in the territory of the Almaty region. According to the results of production tests, it was found that the hydro-mechanical destruction of rocks is especially effective in combination with diamond drill heads with a stepped matrix. The presence of a turbulator-expander in the bottom-hole layout made it possible to significantly increase the amount of incoming sludge of drilled rock in the well sump, especially when drilling wells with a solid face. In comparable geological and technical conditions of drilling wells, serial core sets HQ with a drilling diameter of 95.6 mm had the following indicators: energy consumption – 2.1-2.4 kW / hour, core yield with a diameter of 63 mm – 93%, specific lumpiness of the core – 5-8 pcs / per linear meter of drilling, drilling was carried out at an axial load of 2200-2500 kgf, rotation speed 500-700 rpm. Similar indicators of the downhole layout: energy consumption – 1.2-1.5 kW / hour, core yield – 98-100% with a diameter of 112 mm, specific lumpiness – 2-3 pieces, axial load – 700-900 kgf, rotation speed – 300-400 rpm.