Understanding Field Performance of Paraffin Inhibitors Using Differential Scanning Calorimetry

Abstract

The standard test procedure for paraffin inhibitor evaluations in oil and gas production over the past 20 years has been cold finger analysis. With the emergence of unconventional Canadian oil and gas production from tight reservoirs such as the Montney and Duvernay formations, mounting paraffin treatment issues have been observed. The limitations of cold finger analysis have become increasingly evident when relating product evaluation data to field performance data. Baker Hughes has developed a method to evaluate paraffin inhibitors using differential scanning calorimetry (DSC) that exhibits key improvements over cold finger analysis. The results of an investigation between product evaluation testing through DSC and field performance data is presented. DSC analysis is commonly used in the oil and gas industry for cloud point or wax appearance temperature (WAT) determination of crude oil by detecting the point at which paraffin crystals form. It has commonly been presumed that detection of cloud point shifting can be accomplished with paraffin inhibitor chemistries; however, contradictory evidence obtained through thorough investigation within the industry refutes this claim. This is due to the fact that standard paraffin inhibitors work to disrupt paraffin crystal growth and agglomeration, instead of paraffin crystal suppression. Many programs identified through DSC testing methodology have been successfully implemented in a variety of field applications including both conventional and unconventional production. Moreover, field application monitoring data correlates to product selection and treatment rate data obtained through DSC analysis far better than results acquired through cold finger analysis. Additionally, analysis through DSC is far less susceptible to commonly experienced interferences observed in cold finger analysis such as high asphaltene content of specific crude oils, or paraffin content of condensate. Paraffin inhibitor evaluation through DSC allows for improved understanding of intended paraffin inhibitor programs for oil and gas producers, especially those experiencing difficult to treat paraffin issues in higher temperature tight reservoirs.