Rapid evaluation of the gel strength of GTL products during a prolonged trans-Alaska pipeline shutdown

Abstract

A prolonged winter shutdown of the Trans-Alaska Pipeline (TAPS) could cause the fluid in the pipeline to form a gel with sufficient strength to prevent restart. With the economic viability of a North Slope Gas-To-Liquid (GTL) plant improving, understanding the effect the addition of GTL products to TAPS will have on the gel strength of pipeline fluids is essential to quantify the risk of such a project. This study presents the development of a fast cold ramp technique to predict the gel strength of TAPS fluids. The gel strength of various blend ratios of GTL and crude oil are determined using this fast cold ramp technique and are compared to slow cold ramp gel strength tests performed at Westport Technology Center, Houston. The study found that the gel strength of TAPS fluids may be reduced and controlled by altering the final boiling point of GTL products introduced into the pipeline system.