Time-lapse 3-D seismic monitoring of subsurface rock property changes incurred during reservoir fluid-flow processes is an emerging new diagnostic technology for optimizing hydrocarbon production. I discuss the physical theory relevant for three-phase fluid flow in a producing oil reservoir, and rock physics transformations of fluid-flow pressure, temperature and pore-fluid saturation values to...

Conventional crosswell surveys are expensive because a source must be placed downhole, which means that the hole must be prepped and placed off-line for a number of days. We suggest an interesting but unproven alternative: place a source on the surface, drop a simple obstruction-like device downhole that scatters tube wave arrivals from the surface source, and use the scattered tube waves energ...

The neural network, using an unsupervised generalized Hebbian algorithm (GHA), is adopted to find the principal eigenvectors of a covariance matrix in different kinds of seismograms. We have shown that the extensive computer results of the principal components analysis (PCA) using the neural net of GHA can extract the information of seismic reflection layers and uniform neighboring traces. The ...

Seismic interferometry allows one to create a virtual source inside a medium, assuming a receiver is present at the position of the virtual source. We discuss a method that creates a virtual source inside a medium from reflection data measured at the surface, without needing a receiver inside the medium and, hence, presenting and advantage over seismic interferometry. In addition to the reflect...

Stacks of global seismic data reveal the time and distance dependence of high-frequency (1-hertz) precursors to the seismic phase PKKP. Synthetic seismogram modeling shows that scattering from random small-scale topography at the PKKP core-mantle–boundary reflection point generates precursory arrivals similar to those seen in the data. Models with a root mean square core-mantle–boundary topogra...

To date, the parameters that determine the rupture area of great subduction zone earthquakes remain contentious. On 1 April 2014, the Mw 8.1 Iquique earthquake ruptured a portion of the well-recognized northern Chile seismic gap but left large highly coupled areas un-ruptured. Marine seismic reflection and swath bathymetric data indicate that structural variations in the subducting Nazca Plate ...

Now that the world has well and truly crossed the threshold to the 21st century, it seems timely to review the progress of lithospheric seismic imaging and comment on recent developments in the field. In the context of this special issue, lithospheric seismic imaging refers to any kind of seismic study that gives rise to multidimensional (2-D or 3-D) views of the Earth's interior, from the shal...

among all the geophysical techniques, the magnetotelluric method has improved considerably in recent years and is widely being used in hydrocarbon exploration especially in regions where reflection seismic has difficulties. areas which are covered with high velocity rocks in the near surface are most popular cases. a huge high resolution magnetotelluric investigation was conducted in the sehqan...

[1] We report on seismic and petrological data that provide new constraints on the geological evolution of the Amerasia Basin. A seismic reflection transect across the Makarov Basin, located between the Mendeleev and Lomonosov Ridges, shows a complete undisturbed sedimentary section of Mesozoic/Cenozoic age. In contrast to the Mendeleev Ridge, the margin of the Lomonosov Ridge is wide and shows...