Lu Yang

Date of Award

January 2018

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Petroleum Engineering

First Advisor

Kegang Ling

Abstract

Pipeline blockage, which results from solid and hydrocarbon deposition caused by changes in pressure, temperature, or composition, is a critical issue in oil & gas production and transportation systems. Sometimes blockage, which extends several miles in the long-distance pipeline, can be assumed as a new pipe with a smaller diameter. Therefore, it is imperative to detect the location and size of blockage in pipelines more accurately and efficiently to reduce the number of pipeline accidents.

This paper explores the distribution of pressure and pressure gradient through the pipeline without/with single blockage under different operating conditions. 3-dimensional (3D) computational fluid dynamic (CFD) simulations under steady state are carried out to examine the effects of blockage location, blockage diameter and blockage length. The orthogonal array testing technique is applied to study the extent to which factor affects the pressure drop most.

The dimensionless parameters like dimensionless blockage location, dimensionless blockage diameter, dimensionless blockage length and dimensionless pressure drop, are introduced to evaluate the relationship among the pressure drop and blockage characterizations. Three fitting formulas of dimensionless parameters distribution are proposed and could be used to locate the pipeline blockage and estimate its diameter and length as well.

Finally, laboratory experiments were run to validate the blockage prediction model. The fluid frictional apparatus is modified by replacing part of the pipe with a section of small diameter pipe to simulate the actual partial blockade pipeline. The obtained deviations of pressure drop between the lab experiment result and the prediction model is limited to under 30%. Therefore, the deviation should be taken into account while assessing the blockage through the pipeline based on the blockage prediction model, which also allow the operator to assess partial blockage efficiently and economically.

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