Numerical Simulation of Temperature Field in Indirect Thermal Washing for Wax Cleaning

Abstract

Wax deposition in oil pipelines brings a critical operational challenge in the oil development, and the indirect thermal washing is a most common and effective method of wax cleaning. The temperature field in thermal washing is the basis for making a reasonable plan to wash and remove wax well. In this paper, the wells of sucker rod pump in Da Qing oil field are selected as research objects, a new method which is based on heat-fluid coupling method is proposed for predicting temperature field during the thermal washing process. The temperature field of the annulus of tubing and casing and the temperature field of the annulus of rod and tubing are simulated with different thermal washing parameters. In the indirect thermal washing, the temperature in annulus of tubing and casing gradually decreases from wellhead to the bottom, while the temperature in the annulus of rod and tubing increases from bottom to the wellhead. With the increase of temperature and flow rate of thermal washing fluid, the temperature in annulus of tubing and casing and the temperature in annulus of rod and tubing are both increasing, but the rise rate is different at different depths. Compared to the measured results, the coincidences rate is in the range of 93.67%–99.31%. The research results can guide effectively the thermal washing operation.