The latest version of XDIAG does a much better job of diagnosing the pump condition of Group 2 wells (wells less than 4250’ with plungers of 2.25’’ or above).
The enhancements include better logic for “seeing through” the fluid inertia effects that appear on the downhole pump card to diagnose the mechanical condition of the pump without being thrown off by the humps and other downhole pump card characteristics of Group 2 wells. Also, the new XDIAG saves values that are needed by RODSTAR to better “history match” the measured dynamometer card when the XDIAG file is loaded into RODSTAR. The new XDIAG determines what is the best fluid compressibility index, pump efficiency, and rod-tubing friction for the rod pumping system and passes those values to RODSTAR when the XDIAG file is opened in RODSTAR.
The result of this is much better history matching in RODSTAR when you do the third step of the five step optimization (this is taught in our Rod Pumping Optimization courses). In many cases, no additional changes in the data are needed to get a good match.
Figure 1 shows a “history match” in RODSTAR after loading a new XDIAG file for a Group 2 well with significant fluid inertia effects. This match was obtained without having to change any input variables. The XDIAG file was simply loaded and the run button was pressed without having to make any changes to fluid compressibility, pump efficiency, or rod-tubing friction.