Oilwell Paraffin Prevention Chemicals (March 1975)
Authors: Fulford Richard S. 
Published: December 2007

American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc.

This paper was prepared for the Oklahoma City SPE Regional Meeting, to be held in Oklahoma City, Okla., March 24–25, 1975. Permission to copy is restricted to an abstract of not more than 300 words. Illustrations may not be copied. The abstract should contain conspicuous acknowledgment of where and by whom the paper is presented. Publication elsewhere after publication in the JOURNAL OF presented. Publication elsewhere after publication in the JOURNAL OF PETROLEUM TECHNOLOGY or the SOCIETY OF PETROLEUM ENGINEERS JOURNAL is PETROLEUM TECHNOLOGY or the SOCIETY OF PETROLEUM ENGINEERS JOURNAL is usually granted upon request to the Editor of the appropriate journal provided agreement to give proper credit is made. provided agreement to give proper credit is made. Discussion of this paper is invited. Three copies of any discussion should be sent to the Society of Petroleum Engineers office. Such discussion may be presented at the above meeting and, with the paper, may be considered for publication in one of the two SPE magazines.

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.

Introduction

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.

EXPERIMENTAL

Identification of Oilfield Paraffins

The paraffins were dissolved in heptane and separated into saturate, asphaltene and aromatic fractions by a procedure reported by Graves and Tuggle.