The type curves using pressure/pressure-derivative ratio (PDR) was recently introduced so that the type-curve matching requires the movement of field data only in the horizontal direction. This improvement not only facilities the type-curve matching, but also increases the reliability of analysis results. However, the uniqueness of the results from a type-curve match is still the major concern.

This paper presents a new plotting technique for type curves and field data plot that will eliminate the movement of field data in both directions. The horizontal scales on both type curve and field data plots are fixed by the use of the time/pressure-derivative ratio (TDR) as a parameter in constructing the type curves and field data plot.

The paper concludes that using the proposed type curves with PDR and TDR as parameters will give the automatic alignments on both vertical and horizontal scales. Thus, the movement of data for type-curve matching is not needed. The wellbore storage constant, cD, can be read directly on the horizontal axis at PDR of 1.

The work of this study is limited to the type curves for wells in homogeneous radial systems with wellbore storage and skin.

Keywords:
illustration, type curve, drillstem/well testing, horizontal axis, field data plot, single point, drillstem testing, pressure transient testing, upstream oil & gas, field data
Subjects:
Formation Evaluation & Management, Pressure transient analysis, Drillstem/well testing
Copyright 1989, Society of Petroleum Engineers
You can access this article if you purchase or spend a download.