The disadvantages of conventional seismic tomographic ray tracing and inversion by calculus-based techniques include the assumption of a single ray path for each source– receiver pair, the non-inclusion of head waves, long computation times, and the difficulty in finding ray paths in a complicated velocity distribution. A ray-tracing algorithm is therefore developed using the reciprocity princi...

We introduce a new open-source program for transforming inversion data from the open-source Delivery seismic inversion software to industry-standard cornerpoint grid formats suitable for reservoir modelling and flow simulations. The seismic inversion data produced by Delivery is an array of trace-local stochastic samples from a Bayesian posterior distribution of reservoir layer parameters, whic...

Diierencing of time-dependent seismic monitor surveys requires that datasets are collected and processed consistently. Inconsistencies can result in data diierence noise great enough to obscure any reservoir changes. Inversion applied to each dataset may account for some of these inconsistencies. As an example, if the shape, temporal location, or radiation pattern of the seismic energy source i...

Waveform inversion is a velocity model building technique based on full seismograms as the input and seismic wavefields as the information carrier. Conventional waveform inversion is implemented in the data-domain. Similar techniques can be formulated in the image domain, with seismic image as the input and seismic wavefields as the information carrier. The objective function for image-domain w...

Sorting is a useful predictor for permeability. We show how to invert seismic data for a permeable rock sorting parameter by incorporating a probabilistic rock-physics model with floating grains into a Bayesian seismic inversion code that operates directly on rock-physics variables. The Bayesian prior embeds the coupling between elastic properties, porosity, and the floating-grain sorting param...

We have developed a case study of crosshole seismic tomography with a cross-firing geometry in which seismic sources were placed in two vertical boreholes alternatingly and receiver arrays were placed in another vertical borehole. There are two crosshole seismic data sets in a conventional sense. These two data sets are used jointly in seismic tomography. Because the local sediment is dominated...

A common problem in seismic tomography is the inadequate amount of data required for accurate traveltime inversion. The inherent nature in which data is acquired and the subsurface velocities of the survey area can result in a nonuniform distribution of raypaths. In such instances the statistical nature of tomographic inversion biases the solution to reflect the acquisition instead of the geolo...

north-east khorasan is one of the most active regions in the world because of is setting on the alpine-himalayan belt. historical and geological backgrounds suggest that this region has experienced many destructive earthquakes throughout history. compared with the historical background, the seismicity of the region, in the present century, is better known both from the macroseismic and instrume...

The region of the second ionization of helium in the Sun is a narrow layer near the surface. Ionization induces a local change of the adiabatic exponent Γ1, which produces a characteristic signature in the frequencies of p-modes. By adapting the method developed by Monteiro, Christensen-Dalsgaard & Thompson (1994), we propose a methodology for determining the properties of this region by studyi...