A Leak Localization Model for Gas-Liquid Two-Phase Flows in Nearly Horizontal Pipelines

Abstract

In the oil industry the localization of a leak that occurs in a pipeline is an important piece of information that needs to be obtained before mitigating actions can be taken to remedy the leak effects. In this paper we are particularly interested in testing a leak localization model for two-phase flows based upon the intersection of the hydraulic grade lines emanating from the pipeline ends. This methodology is commonly applied to single-phase-flows. In two-phase flows, the flow-pattern that develops along the entire pipeline upstream and downstream of the leak strongly affects the pressure gradient and has significant influence on the location of the leak. We consider this two-phase flow to be steady and to occur in a nearly horizontal pipeline characterized by the stratified-flow pattern. We also assume that the flow is isothermal with a compressible gas phase and an incompressible liquid phase. The results of the numerical simulations allow the model sensitivity to be studied by changing the leak location, for a given leak magnitude. From this analysis, we may observe how these parameters affect the pressure gradients along the pipeline that develop upstream and downstream of the leak and the model’s ability to predict the leak location.

Numerical study of pipeline leak detection for gas-liquid stratified flow

“…The pressure distribution proved effective and scientific to characterise stratified flow behaviours in this study. The effect of leak on stratified flow behaviours induced by leaks has previously observed similar to the monophase pipeline leakage in the previous study (Figueiredo et al 2017). They concluded that the leak localisation strategy based on the upstream and downstream pressure profiles commonly employed in monophase flow pipeline leakage could be extended to the stratified-flow system.…”

“…However, this study was only limited to a 1-D pipeline, assuming that the pipeline was made up of a series of small segments in which each node along the pipe modelled the local flow characteristics. A similar study presented by Figueiredo et al (2017) investigated the effect of leakage on two-phase flow behaviour in nearly horizontal pipelines. In their study, the impact of longitudinal leak location on stratified flows was investigated.…”

“…From these results, the highest MAD value is 0.263, which shows good agreement between the two data. (Figueiredo et al 2017) that concluded a leak localisation strategy based on the upstream and downstream pressure profiles commonly employed in monophase flow pipeline leakage could be extended to the stratifiedflow model. Therefore, the numerical models and simulation method used in this study have good quality and can well describe the fluids flow parameters distribution of pipeline leakage.…”

Degradation mechanisms associated with metal pipes and the effective impact of LDMs and LLMs in water transport and distribution

“…For example, Kam 105 used a single-dimensional pipeline made up of small networks, wherein one network was used to model flow behavior. In other work, Figuerido et al 106 investigated the dual-phase flow impact of the behavior of leaks in horizontally oriented networks and considered longitudinal leak localization in stratified flows. Figuerido et al 106 determined that stratified flow systems could adopt typical pressure profiles utilized in monophase leaks.…”

“…In other work, Figuerido et al 106 investigated the dual-phase flow impact of the behavior of leaks in horizontally oriented networks and considered longitudinal leak localization in stratified flows. Figuerido et al 106 determined that stratified flow systems could adopt typical pressure profiles utilized in monophase leaks. However, similar to other studies, this research simulated single-dimensional pipelines, which are inadequate for gaining a holistic comprehension of the dynamic nature of multiphase flow networks.…”