Restart time correlation for core annular flow in pipeline lubrication of high-viscous oil

Aniefiok Livinus,Liyun Lao,Hoi Yeung

doi:10.1007/s13202-016-0241-y

Aniefiok Livinus, Liyun Lao + Show 1 more

Open Access

https://doi.org/10.1007/s13202-016-0241-y

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Abstract

One of the fundamental questions that must be addressed in the effective design and operation of pipeline lubrication of heavy oil is; “how much time will be needed to restart a blocked core annular flow (CAF) line after shutdown due to fouling or pump failures”, if the pipe is to be cleaned using water only. In this work, laboratory results of shutdown and restart experiments of high-viscous oil conducted in a 5.5-m-long PVC horizontal pipe with internal diameter of 26 mm are first presented. A new correlation for the prediction of the restart time of a shutdown core annular flow line is then formulated. The predictive capabilities of the correlation are checked against measured restart time and pressure drop evolution data. Somewhat high but still reasonable predictions are obtained. The restart time correlation, together with the associated correlations formulated as well, can be of practical importance during the engineering design of high-viscous oil pipeline transportation facility for predicting restart process.

Highlights

The world’s oil resources are majorly heavy and extra heavy viscous hydrocarbons; they make about 70 % of the world’s total oil resources of 9–13 trillion barrels
One of the fundamental questions that must be addressed in the effective design and operation of pipeline lubrication of heavy oil is; ‘‘how much time will be needed to restart a blocked core annular flow (CAF) line after shutdown due to fouling or pump failures’’, if the pipe is to be cleaned using water only
The predictive capabilities of the correlation are checked against measured restart time and pressure drop evolution data

Summary

Introduction

The world’s oil resources are majorly heavy and extra heavy viscous hydrocarbons; they make about 70 % of the world’s total oil resources of 9–13 trillion barrels. Many countries are moving to increase production, test new technologies and invest in pipeline facilities to ensure that these resources are being produced, transported and processed. Due to their very high viscosity, heavy crude oils cannot be transported with conventional pipelines and require additional treatments. Research articles by Saniere et al 2004, Ghosh et al 2008, Adewusi and Ogunsola 1993, Ngan et al 2007 show that various methods, as presented, of reducing the pressure drop have been studied; these include thermal method, addition of diluent, chemical and water assist. Water assist flow (WAF), or core annular flow (CAF) as it is commonly called, seems to be the most environmentally friendly approach

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