Digitalization of hydraulic rotary drilling process for continuously mechanical profiling of siliciclastic sedimentary rocks

Abstract

Hydraulic rotary drilling can offer the essential information and core samplesa for the researches on solid earth. Recording the factual field drilling data and analyzing the hydraulic rotary coring process are challenging yet promising to utilize the massive drilling information in geophysics and geology. This paper adopts the drilling process monitoring (DPM) technique and records the four parameters of displacement, thrust pressure, upward pressure, and rotation speed in real-time series for profiling the siliciclastic sedimentary rocks along 108 m deep drillhole. The digitalization results with 107 linear zones represent the spatial distribution of drilled geomaterials including superficial deposits (fill, loess, gravelly soil), mudstone, silty mudstone, gritstone, and fine sandstone. The constant drilling speeds varying from 0.018 to 1.905 m/min present the in-situ coring resistance of drilled geomaterials. Furthermore, the constant drilling speeds can identify the strength quality of soils to hard rocks. The thickness distributions of the six basic strength quality grades are presented for all the sedimentary rocks and each individual type of the seven soil and rocks. The in-situ strength profile determined in this paper can be used to assess and evaluate the in-situ mechanical behavior of geomaterial along the drillhole and can provide a new mechanical-based assessment for determining the spatial distribution of geological strata and structures in subsurface. They are important since the same stratum at different depths can have different mechanical behavior. The results provide a novel quantitative measurement for continuously in-situ mechanical profiling by digital drilling data. The findings of the paper can offer a new and effective method for refinement and upgrading of in-situ ground investigation, and can provide researchers and engineers with a novel tool and valuable reference to digitize and utilize factual data of current drilling projects.