Relative Pressure Drop Model for Hydrate Formation and Transportability in Flowlines in High Water Cut Systems

Abstract

Today, oil and gas fields gradually become mature with a high amount of water being produced (water cut (WC)), favoring conditions for gas hydrate formation up to the blockage of pipelines. The pressure drop is an important parameter which is closely related to the multiphase flow characteristics, risk of plugging and security of flowlines. This study developed a model based on flowloop experiments to predict the relative pressure drop in pipelines once hydrate is formed in high water cutsystems in the absence and presence of AA-LDHI and/or salt. In this model, the relative pressure drop during flow is a function of hydrate volume and hydrate agglomerate structure, represented by the volume fraction factor (Kv). This parameter is adjusted for each experiment between 1.00 and 2.74. The structure of the hydrate agglomerates can be predicted from the measured relative pressure drop as well as their impact on the flow, especially in case of a homogeneous suspension of hydrates in the flow.

Formation and Flow Characteristics of Methane Hydrates in High-Pressure Pipelines

“…Pham et al 6 studied the effects of different liquid-phase flow rates and kinetic hydrate inhibitors on the entire process from hydrate formation to plugging under high-water-content conditions. This strategy considerably helped in maintaining the flow of the hydrate slurry and in preventing clogging.…”