PS Wave
Compute Average Sonic Times and Velocities
from Micro Seismic Event
Description

Work is partially supported by the U.S. Department of Energy (DOE) National Energy Technology Laboratory (NETL) under Grant Number DE-FE0002056.

Introduction

The PS Wave web app was designed to allow the user to build a spread sheet of average compression & shear times and velocities from a shallow seismic event in the subsurface within an array of seismic sensors. The program uses and extends the Zone Kluster ("ZeKe") - A Depth Constrained Cluster Analysis web applet to compute "Beds" from log data using digital Log ASCII Standard (LAS) version 2.0 & 3.0 files, which are ordered along the dimensions of depth. Depth Constrained Cluster Analysis appeared in PfEFFER Pro an Excel Spread Sheet Program developed by the Kansas Geological Survey, released 1998. It also appeared in GEMINI (Geo-Engineering Modeling through INternet Informatics) web application developed by Kansas Geological Survey 2000 - 2003. The program allows the user to save the log data averages used to compute the "ďbeds" to a Comma Separated Values (CSV) ASCII file that can be imported into the PS Wave Java Applet. The program can be found at the GEMINI Tools Web site (http://www.kgs.ku.edu/Gemini/Tools/Tools.html) or directly to the Zonation Web Site (http://www.kgs.ku.edu/stratigraphic/ZONATION/). The PS Wave program allows the user to import a LAS version 2.0 or 3.0 file only and will force the user to the Zone Kluster ("ZeKe") - A Depth Constrained Cluster Analysis dialog to create "Beds" before computing the average times or velocities for the compression and shear waves.

A description for the Zone Kluster ("ZeKe") - A Depth Constrained Cluster Analysis web app can be found at http://www.kgs.ku.edu/stratigraphic/ZONATION/description.html.

NOTE: The PS Wave program requires both the Acoustic Transit Time (DTc) and Shear (DTs) log curves to work or the Acoustic Transit Time (DTc) and Litho- Density Logs, i.e. Gamma Ray (GR), Neutron Porosity (NPHI) and Density Porosity (NPHI) computed in a Limestone Matrix or Bulk Density (RHOB) as a minimum from which the Shear (DTs) log curve can be computed from defined Velocity Ratio (Vp/Vs) for specific lithologies, i.e.
Vp/Vs Lithology
1.55 Very Clean Sandstone
1.6 Clean Sandstone
1.68 Shaly Sandstone
1.7 Compact Shale
1.9 Limestone
1.8 Dolomite
1.75 Salt
1.85 Anhydrite
1.59 Coal

Pickett (1963)

The PS Wave web app has 2 sources for importing well data, 1) the userís PC or 2) the Kansas Geological Survey (KGS) Server & ORACLE Database. This program allows the user to import Log, Zonation Output CSV File, Tops, and Geologist Cuttings Report/Core Description. The program basically creates a "spread sheet" of sonic times and velocities by "Bed" Thickness, the PS Wave will merge the Tops data into the spread sheet, which the user can modify. The PS Wave program provides a plot button that allows the user to plot the zonation data as log data in a Profile Plot with the tops and geologist report to visualize the subsurface data. This program then allows the user to save the data in a Comma Separated Values (CSV) file, which can be read by the PS Wave Program or used in another Java program in predicting the depth of the seismic events (TBD).

The program has to be able to read and write to the userís PC and access the Kansas Geological Survey (KGS) Database and File Server. The program does not save your files to KGS, but allows you to access the KGS for well information that may be missing in your Kansas logs. The program does NOT use Cookies or any hidden software it only reads the LAS and CSV files for the PS Wave Session and writes a CSV file to your PC to save data.


Author: John R. Victorine jvictor@kgs.ku.edu

The URL for this page is http://www.kgs.ku.edu/PRS/Ozark/JAVA_SRC/PSWave/index.html