Phase behavior study on gas hydrates formation in gas dominant multiphase pipelines with crude oil and high CO2 mixed gas

Estimation of Thermodynamic Stability of Methane and Carbon Dioxide Hydrates in the Presence of Hydrogen Sulfide

This work presents the effect of hydrogen sulfide gas on the phase behavior of both methane gas hydrate formation and CO₂ gas hydrate formation. For this, the thermodynamic equilibrium conditions for various gas mixtures containing CH₄/H₂S and CO₂/H₂S are initially found by simulation using PVTSim software. These simulated results are compared using an experimental approach and the available literature. Then, the thermodynamic equilibrium conditions generated by simulation are used for generating Hydrate Liquid-Vapor-Equilibrium (HLVE) curves to understand the phase behavior of gases. Further, the effect of hydrogen sulfide on the thermodynamic stability of methane and carbon dioxide hydrates was studied. It was clearly observed from the results that an increase in H₂S composition in the gas mixture decreases the stability of CH₄ and CO₂ hydrates.

Experience of virtual commissioning of a process control system for the production of high-paraffin oil

This work describes the experience in developing and testing software for oil industry automation control systems based on the simulation of technological processes and control systems combined in virtual reality, this approach is called virtual commissioning and is widely used in the world both to create automated process control systems and to simulate interactions between different systems.

Experimental investigation and ANN modelling on CO2 hydrate kinetics in multiphase pipeline systems

Gas hydrates are progressively becoming a key concern when determining the economics of a reservoir due to flow interruptions, as offshore reserves are produced in ever deeper and colder waters. The creation of a hydrate plug poses equipment and safety risks. No current existing models have the feature of accurately predicting the kinetics of gas hydrates when a multiphase system is encountered. In this work, Artificial Neural Networks (ANN) are developed to study and predict the effect of the multiphase system on the kinetics of gas hydrates formation. Primarily, a pure system and multiphase system containing crude oil are used to conduct experiments. The details of the rate of formation for both systems are found. Then, these results are used to develop an A.I. model that can be helpful in predicting the rate of hydrate formation in both pure and multiphase systems. To forecast the kinetics of gas hydrate formation, two ANN models with single layer perceptron are presented for the two combinations of gas hydrates. The results indicated that the prediction models developed are satisfactory as R² values are close to 1 and M.S.E. values are close to 0. This study serves as a framework to examine hydrate formation in multiphase systems.

Gas Hydrate in Oil-Dominant Systems: A Review

Gas hydrate risks minimization in deepsea hydrocarbon flowlines, especially in high water to oil ratios, and is critical for the oil and gas flow assurance industry. Although there are several reviews on gas hydrate mitigation in gas-dominated systems, limited reviews have been dedicated to the understanding and mechanism of hydrate formation and mitigation in oil-dominated systems. Hence, this review article discusses and summarizes the prior studies on the hydrate formation behavior and mitigation in oil-dominated multiphase systems. The factors (such as oil volume or water cut, bubble point, and hydrate formers) that affect hydrate formation in oil systems are also discussed in detail. Furthermore, insight into the hydrate mitigation and mechanism in oil systems is also presented in this review. Also, a detailed table on the various studied hydrate tests in oil systems, including the experimental methods, inhibitor type, conventions, and testing conditions, is provided in this work. The findings presented in this work are relevant for developing the best solution to manage hydrate formation in oil-dominated systems for the oil and gas industry.

Experimental and modeling studies on enhancing the thermodynamic hydrate inhibition performance of monoethylene glycol via synergistic green material

This paper presents an experimental and modeling studies on the thermodynamic inhibition effects of the mixture of monoethlyene glycol (MEG) and glycine (Gly) on the carbon dioxide hydrate phase boundary condition. The monoethlyene glycol and glycine (1:1) mixture inhibition effects were investigated at concentrations of 5, 10, and 15 wt.% and pressure ranges from 2.0–4.0 MPa. The effects of the proposed mixture on the carbon dioxide hydrate phase boundary were evaluated by measuring the dissociation temperature of carbon dioxide hydrate using a T-cycle method. The synergistic effect was evaluated based on comparison with pure MEG and Gly data. The results show that 15 wt.% of MEG and Gly mixture displays the highest inhibition effect compared to the 5 and 10 wt.% mixtures, respectively. However, the synergistic effect is higher at 10 wt.%. Dickens' model was also adopted to predict the phase equilibrium data of CO₂ hydrates in the presence of the mixture. The modified model successfully predicted the data within a maximum error of ± 0.52 K.