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Factors that influence paraffin deposition were investigated in laboratory experiments. An apparatus was built that measures the pressure and flow rate changes caused by pressure and flow rate changes caused by paraffin deposition from crude oil in one-half paraffin deposition from crude oil in one-half inch diameter steel pipe. Experiments were done with and without commercial paraffin prevention chemicals to determine the effectiveness of the chemicals. Several additives altered the flow properties of the waxy crude oil and thus properties of the waxy crude oil and thus prevented paraffin deposition at cold temperatures. prevented paraffin deposition at cold temperatures. The chemicals investigated include polyethylene, ethylene co-polymers, xylene, naphthylene as well as various surfactants sold for paraffin prevention. prevention. Temperature is the most important factor in paraffin deposition, but since crude oils with high wax contents are viscoelastic the flow rate and pressure are also important. As the flow rate decreases high wax crude oils become more viscous.
Paraffin deposition in oil fields is an expensive and time consuming problem. It has been estimated that paraffin control in the domestic production industry costs in excess of five million dollars annually. These are direct costs and do not include production losses, increased horsepower requirements, damage or increased wear to equipment, and manpower attention. This estimate was made in 1969 and inflation since that time may easily have doubled this figure.
Paraffin deposits are normally attributed to cold temperatures, but evaporation of light ends and gases can also cause solids to depose: from the crude oil. Since high-wax crude oils are viscoelastic the flow rate and pressure are also important.
The paraffins were dissolved in heptane and separated into saturate, asphaltene and aromatic fractions by a procedure reported by Graves and Tuggle.