OpenLogPlot Introduction

OpenLogPlot uses three spreadsheet sources, or three sheets of one source spreadsheet, to fully specify a plot. First, there is the Template sheet that provides general plot layout and formatting information, independent of what particular well data is to be shown. Secondly, there is the View sheet that specifies how the data should be displayed in a set of tracks and specifying a number of possible views, each with a scale and depth range. Finally, there is the Data document that contains the actual log and associated data to be displayed within the plot.
fig 001

Template Sheet

Templates are named formats for displaying various data in the log plot. For instance, a "LOG42" vertical grid might be defined as being a four-decade logarithmic scale having solid dark-grey lines every decade on the tenth powers of 2 with dashed light-grey lines intermediate unit. A regular "RESD" curve display may specify a solid, black line, varying between 0.2 on the left and 2000 on the right, with no wrap-around. A "cutoff" colour fill scheme may specify that when the curve is less than a defined cut-off value then there should be a yellow fill between them.

Data Sheet

The Data Sheet contains the actual data required for the plot. Apart from the log data (which will be in consecutive columns by log and rows by depth) we can add discrete data (points), graph data, tops and intervals.

View Sheet

For one particular set of well data, there may be several views that are required by the user. A "full plot" view might show the entire data range over the logged interval at a scale of 1200:1 with a horizontal grid having major lines every 100ft. A "reservoir" view might show the data available over a reservoir interval at a defined scale of 1:200 with a horizontal grid having major lines every 50ft. The View Sheet allows the user to predefine such plots and then select them in the user interface for plot generation. The View Sheet also matches the data with the templates, through the Track definitions. For instance, a "Resistivity Track" can be defined as a three-cm wide track with a "LOG42" vertical grid, displaying the "ILD" data log using an "RESD" curve template and using a "cutoff" fill scheme.