Vibratory drilling of rocks and their classification

Abstract

In the practice of prospecting and exploration works shallow wells in soft sedimentary deposits are drilled mainly by rotary core drilling method or by using extremely backward manual percussive-rotary drilling. Not to mention the latter, core drilling also cannot fully meet the modern requirements of exploration work both in terms of labor productivity and the quantity and quality of samples taken. This is explained, first of all, by the necessity to drastically reduce the drilling parameters (in terms of the rotation speed of the drilling tool and the amount of fluid fed into the well), based on the mandatory conditions of core preservation. If to take into account that the method of “dry grouting” used in practice in order to increase the core yield takes 30% of clean drilling time in each trip (1.2-2 m long), it becomes obvious that this method is unacceptable for drilling in soft sedimentary deposits.