...Fei Wang; Sixin Liu; Xinxin Qu Abstract Traditional straight ray- and curved ray-based tomography algorithms need to perform ray tracing to calculate travel times and construct the Jacobi matrix. We present a crosshole radar traveltime tomography algorithm that is based on the fast marching method...

...Zhong-Min Song; Paul R. Williamson Abstract Crosshole experiments usually have sources and receivers confined to a plane, and it is assumed that there is negligible variation in the properties of the medium normal to this plane. Therefore, the problem appears two-dimensional, except for the sources...

...Zhong-Min Song; Paul R. Williamson; R. Gerhard Pratt Abstract In full-wave inversion of seismic data in complex media it is desirable to use finite differences or finite elements for the forward modeling, but such methods are still prohibitively expensive when implemented in 3-D. Full-wave 2-D...

... from tomography exhibits a rapid lateral velocity change that is not resolved by surface seismic. However, all three methods agree within the limits of their common resolution. The results indicate that RVSP and crosshole tomography can potentially be used to image steeply dipping beds or complex...

... velocities are best determined using direct downhole and crosshole methods. However, for these methods, the drilling and cutting disposal costs are high. Indirect and non-intrusive methods of measuring shear-wave velocities by inversion of Rayleigh-wave dispersion curves offer the possibility of obtaining...

... that the determination of P-, SH- and SV-wave arrivals can be determined precisely in both configurations. The crosshole survey, e.g ., seismic crosshole testing and seismic tomography ( Becht et al ., 2007 ), is a common geophysical method to determine soil dynamic properties with high resolution between...

... discover that analyzing P-wave velocities in the subsurface is a suitable method for our experiment, resulting in a measurement accuracy of 0.2 vol%. We determine that our seismic crosshole setup is able to describe the relation of the rock’s elastic parameter on modified fluid properties at the field...

... inversion method for GPR data is the ray-based approach, which considers only a small amount of information and can therefore only provide limited resolution. In the past few decades, full-waveform inversion (FWI) of crosshole GPR data in the time domain has matured, and it provides inversion results...

..., and that the resistivity model of a volume between boreholes can be accurately reconstructed by using crosshole data. The distributive properties of crosshole electrical potential data obtained by the pole-pole array method have also been examined using the calculated partial derivative of the observed apparent...

...M. Ali C. Tura; Lane R. Johnson; Ernest L. Majer; John E. Peterson Abstract Two diffraction tomography techniques are applied to crosshole field data to detect fractures in granitic rock. The techniques used are the conventional back-propagation method and a new quadratic programming method...

...Shufan Hu; Yonghui Zhao; Tan Qin; Chunfeng Rao; Cong An ABSTRACT Regularization has been an effective technique to provide unique and stable solutions for crosshole ground-penetrating radar (GPR) traveltime tomography. The traditional form of this method, in which a low-order differential operator...

...Changxi Zhou; Wenying Cai; Yi Luo; G. T. Schuster; Sia Hassanzadeh Abstract A hybrid wave-equation traveltime and waveform inversion method is presented that reconstructs the interwell velocity distribution from crosshole seismic data. This inversion method, designated as WTW, retains...

... of the traveltimes is observed. The method is demonstrated on a small synthetic data set, where convergence to the correct solution is achieved in a few iterations.The method is then applied to field data from a crosshole experiment in crystalline rock. The frequency range of the seismograms is 1 to 6.6 kHz...

.... We propose a nonlinear kinematic inversion method for crosshole seismic tomography in composite transversely isotropic media with known dipping symmetry axes. This method is based on a new version of the first-order traveltime perturbation equation. It directly uses the derivative of the phase...

...Bing Zhou; Stewart A. Greenhalgh Abstract We develop a method to obtain 2-D/3-D resistivity images for crosshole dc electric measurements. This imaging procedure consists of two steps: (1) an approximate resistivity image is obtained using a simple projection based on the analytic form...

... or the resolution does not notably improve further. Figure 2. Schematic outline of the proposed optimization procedure. To demonstrate this method, a homogeneous crosshole scenario with a borehole spacing of 50 m and a target horizon of 30 m thickness is considered as outlined in Figure  3...

...Marie Scholer; James Irving; Majken C. Looms; Lars Nielsen; Klaus Holliger Abstract The ground-penetrating radar (GPR) geophysical method has the potential to provide valuable information on the hydraulic properties of the vadose zone because of its strong sensitivity to soil water content...