An experimental design approach for investigating the influence of various factors on wax deposition in production tubing and pipelines

Abstract

This research work employed the design of experiment approach to investigate the influence of various factors including the inhibition concentration, crude oil temperature and speed of rotation on wax deposition in production tubing and pipelines. A combination of Taguchi orthogonal array of designed experiments with a subsequent application of a standard response surface methodology based central composite design was carried out using the StatEase DesignExpert Software Version 12. The individual effects of variables and its interaction effects towards the dependent variables were studied with the shear rate/degree of viscosity reduction taken as the dependent variable. The results of the study showed that less wax deposition inferred from the degree of viscosity reduction was significantly affected by the crude oil temperature and speed of rotation. The 2FI model was selected based on the significant lack of fit obtained. Model equations were derived based on the results and the predicted values of the response (shear rate/degree of viscosity reduction were obtained at a sufficient degree of correlation. Thus, the Design Expert can be a valuable tool to quantify and detect the special relationships of two of more factors known as interactions regarding how these factors could affect a process, especially for screening purpose.