Effect of Compensated Density Logging Tool Calibration on Logging Responses
Xiuming Wang · Well Logging Technology · 2011
The higher measurement value is frequently occurred in the density logging,which is mainly related to calibration of compensated density logging tool.The idea about dual spine-and-ribs plot of calibration model is explained based on the calibration principle of compensated density logging apparatus.Presented is the fundamental equation of compensated density logging.Calculation of 4-point calibration is presented by using 3 groups of actual calibration data.Analyzed systematically are the long and short spacing count rate changes influencing the spine and rib chart and the influence of count rate on the logging responses.Indicated is that when the count rate of low density Mg block increases,corresponding spine angle increases,and when the count rate of high density Al block increases,corresponding spine angle decreases.Minuteness increase of Al block count rate reflects enormous influence on spine angle.By theoretical calculation,concluded is that when Al block long spacing count rate increases 1 unit,density log value of limestone adds 0.032 g/cm3.Instrument historical calibration records have relevance and comparison,and engineer should care about all the historical calibration record to acquire accurate tool calibration value.