Abstract Previously, hydrogeologists and petroleum engineers use seepage experiments to measure permeability. This paper develops a novel method calculate matrix permeability from velocity attenuation of an ultrasonic S-wave. At first, is derived as function frequency when S-wave scans fluid-saturated rock. Substituting the into previous model gives theoretical attenuation, in which nexus param...

optimization of reservoir parameters is an important issue in petroleum exploration and production. the ant colony optimization(aco) is a recent approach to solve discrete and continuous optimization problems. in this paper, the ant colony optimization is usedas an intelligent tool to estimate reservoir rock properties. the methodology is illustrated by using a case study on shear wave velocity...

Profiles of SH waves diffracted around the core (Sd) for three deep events at stations across North America and the Atlantic (4 = 92 ° to 152 °) are used to determine the properties of the lower mantle in the vicinity of the core-manUe boundary (CMB). The S-wave velocity above the CMB is found to be tic = 7.22 __ 0.1 km/sec, in agreement with gross earth models, but higher than previously repor...

Present Earth core models derived from the retrieval of global Earth structure are based on absolute travel times, mostly from the International Seismological Centre (ISC), and/or free-oscillation eigenfrequencies. Many core phase data are left out of these constructions, e.g., PKP differential travel times, amplitude ratios, and waveforms. This study is an attempt to utilize this additional in...

In symptomatic severe aortic regurgitation, left ventricular diastolic pressure increases rapidly, often exceeding left atrial pressure in late diastole. This characteristic hemodynamic change should be reflected in the Doppler mitral inflow velocity, which is the direct result of the diastolic pressure difference between the left ventricle and left atrium. Mitral inflow velocity was obtained b...

AVO studies have enjoyed a mixed success rate in predicting the existence of hydrocarbons in sediments. Sometimes AVO predictions are accurate, but other times they can be quite wrong. It seems likely that the success rate might increase if more sophisticated AVO methods could be employed such as full wave inversion. In fact elastic wave equation inversion has been applied to seismic data with ...

asymptotically exact and nonlocal fourth order nonlinear evolution equations are derived for two coupled fourth order nonlinear evolution equations have been derived in deep water for two capillary-gravity wave packets propagating in the same direction in the presence of wind flowing over water.we have used a general method, based on zakharov integral equation.on the basis of these evolution eq...

Application of nonhydrostatic stress to rock induces velocity anisotropy, causing the S wave to split into two components traveling with somewhat different velocities. Large premonitory changes in the extent of S-wave splitting have been observed for two earthquakes in Nevada. Observations of the difference between the two S-wave velocities may provide a simple method for pedicting earthquakes.

BACKGROUND The role of antiretroviral therapy in acceleration of atherosclerosis in patients with human immunodeficiency virus (HIV) infection is controversial. We hypothesized that aortic stiffness, an early marker of arteriosclerosis, may be increased in HIV patients treated with protease inhibitors. METHODS AND RESULTS In 32 HIV-infected patients treated with protease inhibitors and 32 age...