Intrinsic wave attenuation at seismic frequencies is strongly dependent on rock permeability, fluid properties, and saturation. However, in order to use attenuation as an attribute to extract information on rock/fluid properties from seismic data, experimental studies on attenuation are necessary for a better understanding of physical mechanisms that are dominant at those frequencies. An appropriate laboratory methodology to measure attenuation at seismic frequencies is the forced oscillation method, but technical challenges kept this technique from being widely used. There is a need for the standardization of devices employing this method, and a comparison of existing setups is a step towards it. Here we summarize the apparatuses based on the forced oscillation method that were built in the last 30 years and were used to measure frequency‐dependent attenuation in fluid‐saturated and/or dry reservoir rocks under small strains (10−8–10−5). We list and discuss important technical aspects to be taken into account when working with these devices or in the course of designing a new one. We also present a summary of the attenuation measurements in reservoir rock samples performed with these apparatuses so far.

At seismic frequencies (1–100 Hz), we studied attenuation in the laboratory using the forced oscillation method. We adopted the longitudinal mode of oscillation, which yields the Young's modulus and the corresponding attenuation, here defined as the inverse quality factor. A Fontainebleau sandstone with a porosity of 8% and a permeability of 12 mD was saturated with different fluids and investigated at the confining pressures of 5, 10, and 15 MPa. At all the measured confining pressures, while attenuation was zero for the dry sample, for partial and full water saturation, it gradually increased from nearly zero to ~0.02 with increasing frequency. The sample was then fully saturated with glycerin‐water mixtures of varying viscosities, up to that of glycerin (8, 92, 485, and 1414 cP). At the confining pressure of 5 MPa, a bell‐shaped attenuation curve peaking at ~6 Hz with a magnitude of ~0.11 was observed when the sample was fully saturated with glycerin (1414 cP). A decrease in viscosity of the saturating fluid shifted the attenuation curve to higher frequencies, and an increase in confining pressure caused a decrease in the overall magnitude of attenuation. The data obtained for glycerin were compared to a simple squirt flow model with sufficient agreement, implying that squirt flow is the dominant mechanism responsible for the observed attenuation.

The large amount of data collected with the broadband attenuation vessel (BBAV) and other laboratory devices and analyzed in the last five years sheds light on the physics of wave-induced fluid flow in Berea Sandstone. However, the knowledge is insufficient to fully exploit the physics of seismic wave attenuation in partially saturated rocks. In particular, some technical challenges have limited the depth of research. Soon these challenges will be overcome by the use of fluid-pressure sensors capable of measuring wave-induced fluid pressure in the seismic bandwidth when the sample is under high confining pressures. In addition, a new subresonance apparatus, paired with a micro-CT system, will be used to further investigate the influence of fluid distribution and microstructural features on attenuation.

Blast damage to the tops of coal seams due to incorrect blast standoff distances is a serious issue, costing the industry in Australia about one open‐cut mine for every ten operating mines. The current approach for mapping coal‐seam tops is through drilling and pierce‐point logging. To provide appropriate depth control with accuracy of ±0.2 m for blast hole drilling, it is typically necessary to drill deep reconnaissance boreholes on a 50 m x 50 m grid well in advance of overburden removal. Pierce‐point mapping is expensive and can be inaccurate, particularly when the seam is disturbed by rolls, faults, and other obstacles.Numerical modelling and prototype‐field testing are used in this paper to demonstrate the feasibility of two seismic‐while‐drilling‐based approaches for predicting the approach to the top of coal during blast hole drilling: (i) reverse “walk‐away” vertical seismic profiling recording, in which the drill bit vibration provides the source signal and the geophones are planted on the surface near the drill rig, and (ii) in‐seam seismic recording, in which channel waves, driven by the coupling to the coal of the seismic signal emitted by the approaching drill bit, are guided by the seam to geophones located within the seam in nearby or remote boreholes.

In the present work polyurethane foams containing various content loadings of kenaf fiber and recycled tire rubber particulates were prepared and studied, with the objective of developing alternative composite rigid foams. The influence of the filler content on the foam microstructure and its physical and mechanical behavior has been studied for three different polyurethane resin densities. Microstructural observation on fracture surface of composites was carried out using scanning electron microscopy. It has shown closed spherical cells with reduced size when the fillers are added. Nevertheless, the incorporation of kenaf fiber and recycled tire rubber particulates that refined at 80 mesh led to higher mechanical properties than that unfilled polyurethane foam. A 6% filler content loading exhibited the optimum compression stress and compression modulus, while further increase of filler content loading resulted in decline in mechanical behavior. The presence of larger filler content deteriorated the polyurethane system cellular structure and lead to poor composites strength. Overall, the use of kenaf fiber and recycled tire rubber particulates gives composite foams with comparable mechanical behavior for the studied filler reinforcement level.