The sound field of finite dipole acoustic transducers in a steel tool was investigated and their horizontal by measuring their vertical radiation patterns in water at two different frequencies. Measurements were also made with the tool in scale models representative of sonic logging conditions in the field. A Lucite borehole model was used to represent a soft formation and an Austin Chalk boreh...

This paper analyzes and summarizes the numerous types of variations of groundwater pressures (heads), mid-oceanic ridge borehole temperatures and microseismicity in response to tidal forcing in coastal aquifers and deep sea sediments. Tidally related data obtained from various sources were filtered and processed by means of classical harmonic analysis to extract the amplitudes of pressure and t...

The recently developed smart well technology allows for sectionalized production control by means of downhole inflow control valves and monitoring devices. We consider borehole radars as permanently installed downhole sensors to monitor fluid evolution in reservoirs, and it provides the possibility to support a proactive control for smart well production. To investigate the potential of borehol...

Two modes of flexural waves can be generated by a dipole source in an anisotropic borehole. Their velocities are related to those of the fast and slow shear waves in the formation. The particle motions and the polarization diagrams of the fast and slow flexural waves are measured in borehole models made of phenolite materials with transverse isotropy or orthorhombic anisotropy. The experimental...

Stationary phase solutions for the radiation patterns of borehole sources are commonly used to study the far-field seismic wavefields produced in crosshole or reverse VSP experiments, but they break down when the formation shear wave velocity is less than the tube wave velocity in the source borehole. This is because the tube wave, not the primary source, radiates the dominant shear wave signal...

Sudden falls of large-area hard roofs in a mined area release a large amount of elastic energy, generate dynamic loads, and cause disasters such as impact ground pressure and gas outbursts. To address these problems, in this study, the sleeve fracturing method (SFM) was applied to weaken a hard roof. The numerical simulation software FLAC3D was used to develop three models based on an analysis ...

This paper describes a propagator matrix formulation for the problem of the Stoneley wave propagation in an irregular borehole. This is based on a simple one-dimensional theory that is possible for the low frequency Stoneley wave, because it is a guided wave with no geometrical spreading in the borehole. The borehole and the surrounding formation are modeled by multi-layers discretized along th...

Compositing of borehole assay intervals based on economic aspects is a primary step when the crosssectional method is applied in orebody modelling and mineral resources estimation. The compositing is important because the resulting ore composites eventually determine the outlines of orebody models. However, numerous boreholes and borehole intervals make ore compositing tedious and timeconsuming...

The attenuation of borehole Stoneley waves across a permeable structure (e.g., fractures or fracture zone) is correlated with the permeability of the structure. Using a simplified Biot theory, the structure can be modelled as a permeable porous layer intersecting the borehole. In order to study the effect of such a structure on Stoneley waves and to evaluate the theoretical model, we performed ...

Electrode logging as known in the oil industry is a method for determining the electrical conductivity distribution around a borehole or between two boreholes from the static-field (dc) measurements in the borehole. In this paper , we discuss the reconstruction of the three-dimensional (3-D) conductivity around a borehole in a highly deviated formation with invasion. At this moment, we have not...