Topological modeling of methane hydrate crystallization from low to high water cut emulsion systems

Abstract

of methane hydrate crystallization from low to high water cut emulsion systems. Fluid Phase Equilibria, Elsevier, 2016, 413, pp.ABSTRACT Hydrate formation and remediation in oil flowlines facilities represent a major concern for oil industry in respect of capital and operational costs. It is necessary to have a better understanding on the hydrate formation process to be more efficient in hydrate prevention, especially in respect to additive dosage. This work is a contribution to enhance the knowledge of hydrate formation at high water cuts, by introducing new techniques of analysis in the Archimede flow loop: a Focus Beam Reflectance Measurement (FBRM) probe and a Particle Video Microscope (PVM) probe. These results will be supported by Pressure Drop, Flow Rate, Density and Temperature probes. From experimental observations, a method to determine the continuous phase (water or oil) of the system under flowing is proposed. It is based on the time evolution of the most representative chord class measured by the FBRM. In order to predict morphology and size of hydrates, a topological model was developed. It represents hydrate crystallization from different emulsion systems with and without low dosage of hydrate inhibitor additive (anti-agglomerant type). The key parameters are the gas transfer rate at the gas/liquid interface and at the hydrocarbon/water interface, and the role of the hydrocarbon as gas transfer phase. Gas/liquid transfer is low as water phase remains the continuous phase, but is enhanced as hydrocarbon content is increased. Hydrocarbon gas transfer property is depleted as continuous and rigid crust is formed around droplets, especially in well dispersed emulsions. This behavior is highlighted for experiments without anti-agglomerant additive (AA-LDHI) and at high water cut, as a small fraction of hydrocarbon is well dispersed in the water continuous phase. The maximum hydrate plugging risk is in between 70% and 30% water cut (intermediate and low water cut). In this work, experiments at high water cuts (more than 80%) never plug. In order to prevent agglomeration, the AA-LDHI works better if it shows a secondary surfactant benefit, welldispersing the droplets (and later the formed hydrates) in the continuous phase, which was identified as being preferentially the hydrocarbon phase.

A Multiscale Approach for Gas Hydrates Considering Structure, Agglomeration, and Transportability under Multiphase Flow Conditions: II. Growth Kinetic Model

“…Uncontrolled growth and agglomeration of gas hydrates is reported as the number one problem in assuring flow of oil and gas production 2 . In the first part of this series 3 , we split the complex phenomena of gas hydrates formation under multiphase flow [4][5][6][7] (see as well videos published by Chen et al 8 ) in different size-scales that are capable of explaining their onset, growth, agglomeration and transportability in oil and gas production scenarios. In the second part, we focus on mathematical description of growth kinetics, that is, on determining the gas hydrate formation rate.…”

“…Characteristics of the experiment for methane hydrate formation in the flow loop described by Melchuna et al5 …”

Experimental study of growth kinetics of CO2 hydrates and multiphase flow properties of slurries in high pressure flow systems

“…2,[17][18][19][20][21] A large number of experimental data were obtained, which could simulate the real pipe ow and provide important reference for the elds. Melchuna et al 22 analyzed the inuence of the ow characteristics of the slurry and the crystallization process of methane hydrate in the emulsion system with different water content using a ow loop. Pauchard et al 23 established a model for predicting hydrate particle agglomeration and pressure drop.…”

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

“…Focused Beam Reflectance Measurement (FBRM) and Particle Video Microscope (PVM) probes were used to identify and follow the hydrate formation, agglomeration, and deposition. [15] and gas-lift system [16]; merged in one schema from [15,16].…”