A new experimental method to prevent paraffin-wax formation on the crude oil wells: A field case study in Libya

Wax formation and deposition is one of the most common problems in oil producing wells. This problem occurs as a result of the reduction of the produced fluid temperature below the wax appearance temperature (range between 46 and 50 degrees C) and the pour point temperature (range between 42 and 44 degrees C). In this study, two new methods for preventing wax formation were implemented on three oil wells in Libya, where the surface temperature is, normally, 29 degrees C. In the first method, the gas was injected at a pressure of 83.3 bar and a temperature of 65 degrees C (greater than the pour point temperature) during the gas-lift operation. In the second method, wax inhibitors (trichloroethylene-xylene (TEX), ethylene copolymers and Comb polymers) were injected down the casings together with the gas. Field observations confirmed that by applying these techniques, the production string was kept clean and no wax was formed. The obtained results show that the wax formation could be prevented by both methods.