ACOUSTIC-RESONANCE DETERMINATION OF THE EFFECT OF LIGHT-HYDROCARBONS ON WAX APPEARANCE POINTS IN A NJORD WELL FLUID

Wax formation and deposition in pipelines and process equipment pose s evere problems for petroleum companies, especially during transportati on of crude oil in offshore environments. The light hydrocarbons prese nt in the crude oil can play an important role in the shift of wax app earance points by increasing the solubilities of the heavier component s. The following work was undertaken to study the effect of light hydr ocarbons on wax appearance points in a Njord well fluid for Norsk Hydr o, Norway. An automated high-pressure spherical acoustic resonator (50 .8-mm-diameter) assembly designed and fabricated for that purpose has been used to measure resonance frequencies in a Njord well fluid (stab ilized oil sample) provided by Norsk Hydro and blended with the approp riate amount of a synthetically prepared gaseous mixture containing si x light hydrocarbons (C1 to C6), at pressures from 2 to 107 bar and te mperatures in the range 35 to 50 degrees C. Results on rile present me thod to locate the wax appearance points in the Njord well fluid are p resented. A figure showing experimental wax appearance points as a fun ction of pressure is presented. The results are compared with those pr edicted by the Norsk Hydro model.