Wellbore Dynamics of Kick Evolution Considering Hydrate Phase Transition on Gas Bubbles Surface During Deepwater Drilling

2017 ◽  
Author(s):  
Xiaohui Sun ◽  
Baojiang Sun ◽  
Zhiyuan Wang
Keyword(s):  
Phase Transition ◽  
Mass Transfer ◽  
Void Fraction ◽  
Hydrate Formation ◽  
Stability Field ◽  
Fluid Temperature ◽  
Hydrate Shell ◽  
Free Gas ◽  
Hydrate Phase ◽  
Hydrate Stability

It is of high potential and risk to form gas hydrate along the wellbore in deepwater drilled-kick scenarios. Considering the transient mass transfer process that appears as the hydrate shell renewal at gas-liquid interface, we build a fully coupled hydrodynamic-hydrate model to describe the interaction of hydrate phase transition characteristics and wellbore multiphase flow behaviors. Through comparison with experimental data, the performance of proposed model is validated and evaluated. The simulation results show that the hydrate formation region is mainly near the seafloor affected by the fluid temperature and pressure distributions along the wellbore. The volume change and mass transfer over a hydrate coated moving bubble, vary complicatedly, because of the hydrate formation, hydrate decomposition and bubble dissolution (both gas and hydrate). Overall, hydrate phase transition can significantly alter the void fraction and migration velocity of free gas in two aspects: (1) when gas enters the hydrate stability field, a solid hydrate shell will form around the gas bubble, and thereby the velocity and void fraction of free gas can be considerably decreased; (2) the free gas will separate from solid hydrate and expand rapidly near the sea surface (out of hydrate stability field), which can lead to an abrupt hydrostatic pressure loss and explosive development of kick accident. These two phenomena generated by hydrate phase transition can make deepwater gas kick to be “hidden” and “abrupt” successively, and present challenges to early kick detection and wellbore pressure management.

A Model of Multiphase Flow Dynamics Considering the Hydrated Bubble Behaviors and Its Application to Deepwater Kick Simulation

2018 ◽  
Vol 140 (8) ◽  
Author(s):  
Xiaohui Sun ◽  
Baojiang Sun ◽  
Yonghai Gao ◽  
Zhiyuan Wang
Keyword(s):  
Heat Transfer ◽  
Multiphase Flow ◽  
Void Fraction ◽  
Mass Transfer Rate ◽  
Hydrate Formation ◽  
Flow Dynamics ◽  
Fluid Temperature ◽  
Hydrate Shell ◽  
Free Gas ◽  
Mass And Heat Transfer

The interaction between hydrated bubble growth and multiphase flow dynamics is important in deepwater wellbore/pipeline flow. In this study, we derived a hydrate shell growth model considering the intrinsic kinetics, mass and heat transfer, and hydrodynamics mechanisms in which a partly coverage assumption is introduced for elucidating the synergy of bubble hydrodynamics and hydrate morphology. Moreover, a hydro-thermo-hydrate model is developed considering the intercoupling effects including interphase mass and heat transfer, and the slippage of hydrate-coated bubble. Through comparison with experimental data, the performance of proposed model is validated and evaluated. The model is applied to analyze the wellbore dynamics process of kick evolution during deepwater drilling. The simulation results show that the hydrate formation region is mainly near the seafloor affected by the fluid temperature and pressure distributions along the wellbore. The volume change and the mass transfer rate of a hydrated bubble vary complicatedly, because of hydrate formation, hydrate decomposition, and bubble dissolution (both gas and hydrate). Moreover, hydrate phase transition can significantly alter the void fraction and migration velocity of free gas in two aspects: (1) when gas enters the hydrate stability field (HSF), a solid hydrate shell will form on the gas bubble surface, and thereby, the velocity and void fraction of free gas can be considerably decreased; (2) the free gas will separate from solid hydrate and expand rapidly near the sea surface (outside the HSF), which can lead to an abrupt hydrostatic pressure loss and explosive development of the gas kick.

scholarly journals Enthalpies of Hydrate Formation and Dissociation from Residual Thermodynamics

Energies ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4726 ◽  
Author(s):  
Solomon Aforkoghene Aromada ◽  
Bjørn Kvamme ◽  
Na Wei ◽  
Navid Saeidi
Keyword(s):  
Phase Transition ◽  
Phase Transitions ◽  
Gas Hydrate ◽  
Hydration Number ◽  
Hydrate Formation ◽  
Formation Enthalpy ◽  
Hydrate Dissociation ◽  
Enthalpy Changes ◽  
Hydrate Phase ◽  
Temperature Equilibrium

We have proposed a consistent thermodynamic scheme for evaluation of enthalpy changes of hydrate phase transitions based on residual thermodynamics. This entails obtaining every hydrate property such as gas hydrate pressure-temperature equilibrium curves, change in free energy which is the thermodynamic driving force in kinetic theories, and of course, enthalpy changes of hydrate dissociation and formation. Enthalpy change of a hydrate phase transition is a vital property of gas hydrate. However, experimental data in literature lacks vital information required for proper understanding and interpretation, and indirect methods of obtaining this important hydrate property based on the Clapeyron and Clausius-Clapeyron equations also have some limitations. The Clausius-Clapeyron approach for example involves oversimplifications that make results obtained from it to be inconsistent and unreliable. We have used our proposed approach to evaluate consistent enthalpy changes of hydrate phase transitions as a function of temperature and pressure, and hydration number for CH4 and CO2. Several results in the literature of enthalpy changes of hydrate dissociation and formation from experiment, and Clapeyron and Clausius-Clapeyron approaches have been studied which show a considerable disagreement. We also present the implication of these enthalpy changes of hydrate phase transitions to environmentally friendly production of energy from naturally existing CH4 hydrate and simultaneously storing CO2 on a long-term basis as CO2 hydrate. We estimated enthalpy changes of hydrate phase transition for CO2 to be 10–11 kJ/mol of guest molecule greater than that of CH4 within a temperature range of 273–280 K. Therefore, the exothermic heat liberated when a CO2 hydrate is formed is greater or more than the endothermic heat needed for dissociation of the in-situ methane hydrate.

scholarly journals Hydrate Phase Transition Kinetic Modeling for Nature and Industry–Where Are We and Where Do We Go?

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4149
Author(s):  
Bjørn Kvamme ◽  
Matthew Clarke
Keyword(s):  
Phase Transition ◽  
Natural Gas ◽  
Kinetic Modeling ◽  
Hydrate Formation ◽  
Nucleation Theory ◽  
Classical Nucleation Theory ◽  
Massive Growth ◽  
Hydrate Phase ◽  
Induction Times ◽  
Classical Thermodynamics

Hydrate problems in industry have historically motivated modeling of hydrates and hydrate phase transition dynamics, and much knowledge has been gained during the last fifty years of research. The interest in natural gas hydrate as energy source is increasing rapidly. Parallel to this, there is also a high focus on fluxes of methane from the oceans. A limited portion of the fluxes of methane comes directly from natural gas hydrates but a much larger portion of the fluxes involves hydrate mounds as a dynamic seal that slows down leakage fluxes. In this work we review some of the historical trends in kinetic modeling of hydrate formation and discussion. We also discuss a possible future development over to classical thermodynamics and residual thermodynamics as a platform for all phases, including water phases. This opens up for consistent thermodynamics in which Gibbs free energy for all phases are comparable in terms of stability, and also consistent calculation of enthalpies and entropies. Examples are used to demonstrate various stability limits and how various routes to hydrate formation lead to different hydrates. A reworked Classical Nucleation Theory (CNT) is utilized to illustrate that nucleation of hydrate is, as expected from physics, a nano-scale process in time and space. Induction times, or time for onset of massive growth, on the other hand, are frequently delayed by hydrate film transport barriers that slow down contact between gas and liquid water. It is actually demonstrated that the reworked CNT model is able to predict experimental induction times.

Mathematical model of multiphase flow propagation for the case of underwater pipeline damage

2019 ◽  
Vol 14 (2) ◽  
pp. 142-147
Author(s):  
S.R. Kildibaeva ◽  
E.T. Dalinskij ◽  
G.R. Kildibaeva
Keyword(s):  
Oil And Gas ◽  
Control Volume ◽  
Hydrate Formation ◽  
Initial Moment ◽  
Hydrate Shell ◽  
Surrounding Water ◽  
Vertical Coordinate ◽  
Associated Gas ◽  
First Case ◽  
Underwater Pipeline

The paper deals with the case of damage to the underwater pipeline through which oil and associated gas are transported. The process of oil and gas migration is described by the flow of a multiphase submerged jet. At the initial moment, the temperature of the incoming hydrocarbons, their initial velocity, the temperature of the surrounding water, the depth of the pipeline is known. The paper considers two cases of different initial parameters of hydrocarbon outflow from the pipeline. In the first case, the thermobaric environmental conditions correspond to the conditions of hydrate formation and stable existence. Such a case corresponds to the conditions of the hydrocarbons flow in the Gulf of Mexico. In the second case, hydrate is not formed. Such flows correspond to the cases of oil transportation through pipelines in the Baltic sea (for example, Nord stream–2). The process of hydrate formation will be characterized by the following dynamics of the bubble: first, it will be completely gas, then a hydrate shell (composite bubble) will begin to form on its surface, then the bubble will become completely hydrate, which will be the final stage. The integral Lagrangian control volume method will be considered for modeling the dynamics of hydrocarbon jet propagation. According to this method, the jet is considered as a sequence of elementary volumes. When modeling the jet flow, the laws of conservation of mass, momentum and energy for the components included in the control volume are taken into account. The equations are used taking into account the possible formation of hydrate. Thermophysical characteristics of hydrocarbons coming from the damaged pipeline for cases of deep-water and shallow-water pipeline laying are obtained. The trajectories of hydrocarbon migration, the dependence of the jet temperature and density on the vertical coordinate are analyzed.

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