Wax Deposition Characterization under Flowing Conditions Using an Oscillatory Flow Setup

Abstract

Wax deposition is a significant flow assurance issue in oil/gas production and transportation, often leading to significant flow constrictions with eventual blockages of flowlines. Wax deposition issues are generally studied using flow loops and ex-situ measurement methods to determine the amount of wax deposition. In this work, we introduce a new benchtop system for wax deposition combined with methods for deposit thickness, distribution, and wax content measurements. Results are shown for both long and short-term wax tests to characterize the evolution of deposit thickness and wax content. Results show that extra deposition will occur during the pigging process and lead to an overestimation of the average deposit thickness from traditional measurement methods; however, it can be overcome by using the new test-needle measuring system. Moreover, a time-varying deposition mechanism is suggested, where deposit thickening is dominated in short-term deposition by the fast formation of a gel layer, and wax accumulation is dominated in long-term deposition, resulting in the hardening of the deposit. Overall, the results highlight the features of our new experimental system for wax deposition test and characterization, which are much needed to advance our understanding on this important flow assurance issue.