| Abstract: |
Chemical demulsifiers are routinely added in the oilfield to effectively resolve water-in-crude oil emulsions. As used in the common bottle test, demulsifiers in effect probe or interrogate emulsion stability strength. Emulsion stability in turn is defined by no less than three parameters - water drop, oil dryness and interface quality. All three parameters are direct outputs of the bottle test, and collectively, all three provide a more complete picture of emulsion stability as opposed to the use of any singular parameter. By selecting a wide variety of demulsifiers and performing a standardized bottle test (as introduced in SPE 84610), emulsion stability from a variety of sites can be quantified and compared. By coupling bottle test results with corresponding crude oil analytical data, fundamental questions concerning factors governing emulsion stability can be quantified. The results show that solid content, not asphaltene content or any other crude oil parameter investigated, is by far the best single predictor for gauging emulsion stability. Furthermore, statistical analysis via partition trees shows that emulsion stability is most aptly described using several input parameters as opposed to a single factor. This statistical technique produces emulsion stability descriptions with Rsquare values on the order of 0.9. Copyright 2005, Society of Petroleum Engineers Inc. |
