Approximately 100 pressure pulse workovers have been performed on heavy oil wells in Canada since 1998. Analysis of a number of the wells shows varying degrees of success, but in general, the workovers have paid for themselves in almost all recent cases. Although there is insufficient information to fully prove hypotheses using statistical criteria, it appears that pressure pulse workovers have particular application in three situations:
In cases where the CHOPS well did not initially start producing sand during the primary completion attempts;
In cases where the well became disconnected from the far-field pressure and gravity driving forces; and,
In cases when it is desired to place a workover chemical in a well-dispersed fashion around a well.
This article will review the physical mechanisms and drive energy sources that are believed to be responsible for CHOPS production; it will also present the physical processes that we believe occur during aggressive pressure pulse workovers around a heavy oil well.