Anastasia Felixovna Stroujkova

Predicting seismic velocity and other rock properties from clay content only

It has been shown that accurate predictions of compressional and shear‐wave velocities can be derived from measurements of clay content, porosity, and bulk density. In this paper, we test the efficacy of using a sequence of established petrophysical formulations to go a step further and predict porosity and bulk density as well as velocity from clay content alone. Other variables, like grain and pore‐fluid properties, are assumed to be constant, while empirical relationships are used to model such behaviors as grain packing and compaction.The sequence of formulations, referred to as the “model,” is evaluated using well‐log and core data from the Amazon Fan collected during Ocean Drilling Program Leg 155. Clay contents are estimated from the borehole gamma‐ray logs. These are input to the model, which in turn predicts observed porosities to a rms error of <20%, and bulk densities and compressional velocities to rms errors of ≤10%. The results suggest that with better measurements of clay content and improv...

A Comprehensive Study of Fracture Patterns and Densities in The Geysers Geothermal Reservoir Using Microearthquake Shear-Wave Splitting Tomography

In this project we developed a method for using seismic S-wave data to map the patterns and densities of sub-surface fractures in the NW Geysers Geothermal Field/ (1) This project adds to both the general methods needed to characterize the geothermal production fractures that supply steam for power generation and to the specific knowledge of these in the Geysers area. (2)By locating zones of high fracture density it will be possible to reduce the cost of geothermal power development with the targeting of high production geothermal wells. (3) The results of the project having been transferred to both US based and international geothermal research and exploration agencies and concerns by several published papers and meeting presentations, and through the distribution of the data handling and other software codes we developed.