One of the main flow assurance challenges in the oil industry is wax deposition. It can result in the restriction of crude oil flow in the pipeline, creating pressure abnormalities and causing an artificial blockage leading to a reduction in the production. Wax can precipitate as a solid phase on the pipe wall when its temperature drops below the Wax Appearance Temperature. The objective of this study is using spiral flow to mitigate wax deposition.
An experimental flow loop system was built in the lab to study the variation of wax deposition thickness under the single phase transport. A series of experiments were carried out at different flow rates (2.7 and 4.8 L/min) to study wax deposition and measure the wax thickness. The effect of factors on wax formation such as spiral flow, inlet coolant temperature, pressure drop, temperature drop, flow rates, time and shear stress have been examined.
The spiral flow created inside the pipe by inserting a twisted metal along the pipe, which will create high shear stress affecting to wax deposition. The results show that the wax inhibition percentage WI % by using the spiral flow at flow rate 2.7 L/min, inlet coolant temperature14 °C, was 65%. At flow rate 4.8 L/min, inlet coolant temperature 14 °C the wax inhibition percentage was 73%. Experimentally, it was found the spiral flow more efficient than the chemical inhibitors. The WI % increased, by merging the effect of the spiral flow and the inhibitor at flow rate 2.7 L/min, to 75, 92.2 and 100 % at inlet coolant temperatures 14, 24 and 33 °C, respectively. The WI % was increased by combining the influence of the spiral flow and the inhibitor to 4.8 L/min, to 83.5% at inlet coolant temperature 14 °C, 94.3% at 24 °C and to 100% at temperature 33 °C.
This percentage of inhibition will increased rapidly by increasing the inlet coolant temperature and decreased by reducing the inlet coolant temperature.
This technique of creating spiral flow inside the test section of the pipe will provide a step forward in flow assurance technology to mitigate the deposition of wax.