Study on Restart Safety of Waxy Crude Pipelines Based on Reliability Principle under Constant Flow

Abstract

The restart process of waxy crude pipelines is an unsteady thermo-hydraulic coupling process, which mainly includes two modes of the constant flow and constant pressure in industry. However, some parameters involved in the restart process have obvious uncertainties, such as the operating parameters, physical parameters of crude oil, environmental parameters, and pipeline parameters, resulting in the traditional deterministic method that cannot scientifically describe the safety of the pipeline restart process. To do this, this study introduces the reliability-based limit state method and interference principle into the safety evaluation of waxy crude pipelines during the restart process. Considering the random fluctuation characteristics of the mentioned parameters, the restart physical process, the flow and heat transfer mathematical model, and the restart failure limit state function were established. On this basis, the failure probability during the restart process for one waxy crude pipeline under constant flow was determined. This research has realized the quantitative evaluation of restart safety of waxy crude pipelines.

Analyzing the Role of Wax Crystal Morphology in Wax Inhibition Using Polymeric Additive

“…The gelation of crude oil may cause complete blockage of pipelines . In such a case, if the pipeline fails to restart, huge expenses may incur to resolve the issue. , …”

“…15 In such a case, if the pipeline fails to restart, huge expenses may incur to resolve the issue. 16,17 Different techniques that may be classified into thermal, mechanical, or chemical are applied for flow assurance of the transportation pipelines. 14 The use of low-cost additives as wax inhibitors is an economical option for comparatively longer pipelines.…”

Viscoelastic Behavior and Constitutive Relation of Heavy Crude Oils

“…The mining of heavy crude oil is becoming more important to supply fuel for economic development. However, due to the different components of saturates, aromatics, resins, and asphaltenes, most heavy crude oils demonstrate some complex rheological behaviors, such as shear thinning, thixotropy, and viscoelasticity. , The rheological behaviors of heavy crude oil are very complex and are different from those of light crude oil. Therefore, they have a great influence on the production of heavy crude oil, especially on the processes of mining and transportation …”