Thermal, Macroscopic, and Microscopic Characteristics of Wax Deposits in Field Pipelines

Abstract

Wax deposition is an important issue in crude oil transportation. Understanding the deposit properties assists in making a suitable schedule for removing wax deposits. However, there was little work published on the nature of wax deposits in field pipelines. This study focuses on the thermal, macroscopic, and microscopic characteristics of wax deposits obtained from the field pipelines. First, differential scanning calorimetry (DSC) was used to investigate the thermal properties of wax deposits and crude oils. The results showed that the wax appearance temperature (WAT) and wax content of wax deposits is much higher than that of crude oils, and both of two parameters increase with the increasing radial distances. For all deposits, the precipitated wax concentration increases significantly with the decreasing temperature near the WAT, while it almost increases linearly when the temperature decreases about 25 °C below the WAT. Based on DSC results, a correlation between the solid wax content and wax content...