As discussed in previous news-letters, we have developed special expert routines that detect and correct errors from pump off controllers caused by an incorrect top of stroke setting, incorrect position data from a position switch, or a phase shift caused by the time difference between load and position measurements.
These new capabilities have been fully implemented in the new versions of XDIAG and XSPOC and have been deployed in all locations where XSPOC is used. This has made a dramatic difference in the results and in the accuracy of the expert analysis generated by XDIAG.
Another new feature added to XSPOC and XDIAG is the ability to apply a fixed load correction to all dynamometer cards from a certain POC and for each separate well. This was necessary because when the load cell was significantly off, XDIAG would correct it, but the correction was not consistent for different dynamometer cards from the well. For example, XDIAG may have detected a load shift of 20% for one dynamometer card, a 22% load shift for the next one, etc. This is because XDIAG looks at one dynamometer card at a time. In most cases this is not a problem.
Some of our customers wanted to do frequent analyses on a well to detect trends in minimum polished rod load or compression at the bottom section of the rod string, to study the effect of chemical injection, etc. However, this variability in the load correction did not allow them to obtain meaningful and effective trend plots. To fix this problem, we now allow the user to select a load cell correction that is applied every time a new dynamometer card is analyzed for this well. This keeps the load correction the same for each dynamometer card and allows one to get valid trends for any variable under study.