Currently, visually described borehole samples are the primary input for large-scale 3D geological models of the subsurface, both when modelling architecture and composition. Cone penetration tests are rarely used and to a limited extent only. There are several reasons why it is of interest to utilize CPT data for geological and lithological modelling of the Dutch subsurface: 1) CPTs are more a...

Rock mass description and characterisation is a basic task for exploration, mining work-flows and ground-water studies. Rock analysis can be performed using borehole logs that are created using a televiewer. Planar discontinuities in the rock appear as sinusoidal curves in borehole logs. The aim of this project is to develop a fast algorithm to analyse borehole imagery using image processing te...

The elastodynamic body-wave field outside a fluid-filled open borehole due to a monopole source in the fluid, is reduced to the radiation-field due to a suitable equivalent force system (EFS) in the absence of the borehole, consisting of a monopole plus a vertical dipole. Theoretical seismograms of the EFS displacements in the solid are shown to be in excellent agreement with those obtained fro...

Machine learning is the main technical means for lithofacies logging identification. As target of shale oil spatial distribution prediction, mud petrography subjected to constraints stratigraphic inhomogeneity and information redundancy. Therefore, choosing most applicable machine method different geological characteristics data situations one key aspects high-precision However, only a few stud...

Multi-offset, single-hole, borehole-radar reflection surveys were conducted at the U.S. Geological Survey Fractured Rock Research Site at Mirror Lake, in Grafton County, New Hampshire. The study was conducted to evaluate the benefits of applying multi-offset seismic processing techniques to borehole-radar reflection surveys in fractured rock. The multi-offset reflection surveys were conducted i...

Borehole radar can be used in a single-hole reflection mode or in a cross-hole tomography mode. In the reflection mode, radar provides an image of discontinuities in the bedrock surrounding a borehole, including bedding planes, lithologic contacts, fractures, and cavities. The measurements are either directional or omnidirectional, depending upon the type of equipment and antennas. In the tomog...

Near a borehole, stress concentration effects may cause a complex spatial variation of elastic anisotropy. Stress-induced sonic anisotropy results when moduli and velocities are stress dependent and the state of stress is nonhydrostatic. For such cases, the appropriate material model is that of an elastic orthorhombic medium with material axes aligned with the principal axes of stress. We simul...