Scaling Analysis and Its Implication for Asphaltene Deposition in a Wellbore

Abstract

Summary The study presented here uses order-of-one—or o(1)—scaling analysis to identify dimensionless groups specific to asphaltene deposition along production tubing. The precipitation and subsequent deposition of asphaltene can lead to significant complications related to oilfield production. Aside from the many complications within a reservoir as well as surface equipment, the reduction in cross-sectional area caused by its deposition leads to increased pressure losses, reductions in volumetric flow capacity, and possible flow perturbations within a wellbore. Attempts to mitigate these adverse effects have focused on both hindering the precipitation of asphaltene and preventing its deposition after precipitated. The study used here attempts to quantify various hydrodynamic controls specific to asphaltene deposition. With o(1) scaling analysis, four independent dimensionless groups were generated from momentum and mass-balance equations relating hydrodynamic effects to the rate of asphaltene deposition. The dimensionless group π4 was of particular interest because of its inherent relationship to the rate of deposition. This group was compared with both data and existing correlations taken from literature, and noticeable trends in the deposition rate with respect to average stream velocity were observed. One of the most important trends discerned by these comparisons was a clear distinction whereby the rate of asphaltene deposition, related through π4, decreases with increasing Reynolds numbers (Re) in lower ranges, but actually increases in higher ranges. Although the data did not cover the specific region of transition, various correlations suggest a clear cutoff between what was deemed a favorable regime, or Regime I, and a nonfavorable regime, or Regime II.