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Hot Oil Problems

One of the main problems with using hot oil for paraffin removal, is that it can actually induce formation damage into the well [1].

During regular operations, stock tank oil is heated to a fairly high temperature (above 120°C, 250°F) and injected into the annulus of the wellbore between the casing and the tubing. As the hot oil descends, the temperature drops rapidly as the heat is drawn away by the surface area of the tubing.

Straub[2] presents an actual example where a hot oil treatment failed to raise the bottomhole temperature and had actually reduced the temperature from 52°C down to 46°C. Temperature changes such as these can actually cause deposition of paraffin downhole. The same hot oil treatment intended to remove paraffin, can actually cause paraffin to be deposited.

REFERENCES

[1] Mansure, A.J. and Barker, K.M., “Insight Into Good Hot Oiling Practices,” presented at the SPE Production Operations Symposium, Oklahoma, March 21-23 (1993).

[2] Straub, T.J., Autry, S. W., and King, G.E.., “An Investigation Into Practical Removal of Downhole Paraffin by Thermal Methods and Chemical Solvents,”, presented at the SPE Production Operations Symposium, Oklahoma, March 13-14 (1989).