scholarly journals Formation of natural gas hydrates in marine sediments: 1. Conceptual model of gas hydrate growth conditioned by host sediment properties

1999 ◽  
Vol 104 (B10) ◽  
pp. 22985-23003 ◽  
Author(s):  
M. Ben Clennell ◽  
Martin Hovland ◽  
James S. Booth ◽  
Pierre Henry ◽  
William J. Winters
Keyword(s):  
Natural Gas ◽  
Conceptual Model ◽  
Marine Sediments ◽  
Gas Hydrates ◽  
Gas Hydrate ◽  
Sediment Properties ◽  
Natural Gas Hydrates ◽  
Host Sediment

Formation of Natural Gas Hydrates in Marine Sediments: Gas Hydrate Growth and Stability Conditioned by Host Sediment Properties

2006 ◽  
Vol 912 (1) ◽  
pp. 887-896 ◽  
Author(s):  
M. BEN CLENNELL ◽  
PIERRE HENRY ◽  
MARTIN HOVLAND ◽  
JAMES S. BOOTH ◽  
WILLIAM J. WINTERS ◽  
...  
Keyword(s):  
Natural Gas ◽  
Marine Sediments ◽  
Gas Hydrates ◽  
Gas Hydrate ◽  
Sediment Properties ◽  
Natural Gas Hydrates ◽  
Host Sediment

MRI Visualization of Spontaneous Methane Production From Hydrates in Sandstone Core Plugs When Exposed to CO2

SPE Journal ◽  
2008 ◽  
Vol 13 (02) ◽  
pp. 146-152 ◽  
Author(s):  
Arne Graue ◽  
B. Kvamme ◽  
Bernie Baldwin ◽  
Jim Stevens ◽  
James J. Howard ◽  
...  
Keyword(s):  
Natural Gas ◽  
Gas Hydrates ◽  
Gas Hydrate ◽  
Methane Production ◽  
Methane Hydrate ◽  
Co2 Storage ◽  
Natural Gas Hydrate ◽  
Hydrate Dissociation ◽  
Natural Gas Hydrates ◽  
The Stability

Summary Magnetic resonance imaging (MRI) of core samples in laboratory experiments showed that CO2 storage in gas hydrates formed in porous rock resulted in the spontaneous production of methane with no associated water production. The exposure of methane hydrate in the pores to liquid CO2 resulted in methane production from the hydrate that suggested the exchange of methane molecules with CO2 molecules within the hydrate without the addition or subtraction of significant amounts of heat. Thermodynamic simulations based on Phase Field Theory were in agreement with these results and predicted similar methane production rates that were observed in several experiments. MRI-based 3D visualizations of the formation of hydrates in the porous rock and the methane production improved the interpretation of the experiments. The sequestration of an important greenhouse gas while simultaneously producing the freed natural gas offers access to the significant amounts of energy bound in natural gas hydrates and also offers an attractive potential for CO2 storage. The potential danger associated with catastrophic dissociation of hydrate structures in nature and the corresponding collapse of geological formations is reduced because of the increased thermodynamic stability of the CO2 hydrate relative to the natural gas hydrate. Introduction The replacement of methane in natural gas hydrates with CO2 presents an attractive scenario of providing a source of abundant natural gas while establishing a thermodynamically more stable hydrate accumulation. Natural gas hydrates represent an enormous potential energy source as the total energy corresponding to natural gas entrapped in hydrate reservoirs is estimated to be more than twice the energy of all known energy sources of coal, oil, and gas (Sloan 2003). Thermodynamic stability of the hydrate is sensitive to local temperature and pressure, but all components in the hydrate have to be in equilibrium with the surroundings if the hydrate is to be thermodynamically stable. Natural gas hydrate accumulations are therefore rarely in a state of complete stability in a strict thermodynamic sense. Typically, the hydrate associated with fine-grain sediments is trapped between low-permeability layers that keep the system in a state of very slow dynamics. One concern of hydrate dissociation, especially near the surface of either submarine or permafrost-associated deposits, is the potential for the release of methane to the water column or atmosphere. Methane represents an environmental concern because it is a more aggressive (~25 times) greenhouse gas than CO2. A more serious concern is related to the stability of these hydrate formations and its impact on the surrounding sediments. Changes in local conditions of temperature, pressure, or surrounding fluids can change the dynamics of the system and lead to catastrophic dissociation of the hydrates and consequent sediment instability. The Storegga mudslide in offshore Norway was created by several catastrophic hydrate dissociations. The largest of these was estimated to have occurred 7,000 years ago and was believed to have created a massive tsunami (Dawson et al. 1988). The replacement of natural gas hydrate with CO2 hydrate has the potential to increase the stability of hydrate-saturated sediments under near-surface conditions. Hydrocarbon exploitation in hydrate-bearing regions has the additional challenge to drilling operations of controlling heat production from drilling and its potential risk of local hydrate dissociation (Yakushev and Collett 1992). The molar volume of hydrate is 25-30% greater than the volume of liquid water under the same temperature-pressure conditions. Any production scenario for natural gas hydrate that involves significant dissociation of the hydrate (e.g., pressure depletion) has to account for the release of significant amounts of water that in turn affects the local mechanical stress on the reservoir formation. In the worst case, this would lead to local collapse of the surrounding formation. Natural gas production by CO2 exchange and sequestration benefits from the observation that there is little or no associated liquid water production during this process. Production of gas by hydrate dissociation can produce large volumes of associated water, and can create a significant environmental problem that would severely limit the economic potential. The conversion from methane hydrate to a CO2 hydrate is thermodynamically favorable in terms of free energy differences, and the phase transition is coupled to corresponding processes of mass and heat transport. The essential question is then if it is possible to actually convert methane hydrate as found in sediments to CO2 hydrate. Experiments that formed natural gas hydrates in porous sandstone core plugs used MRI to monitor the dynamics of hydrate formation and reformation. The paper emphasizes the experimental procedures developed to form the initial natural gas hydrates in sandstone pores and the subsequent exchange with CO2 while monitoring the dynamic process with 3D imaging on a sub millimetre scale. The in-situ imaging illustrates the production of methane from methane hydrate when exposed to liquid CO2 without any external heating.

scholarly journals Study on the decomposition mechanism and kinetic model of natural gas hydrate slurry in water-in-oil emulsion flowing systems

RSC Advances ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 3879-3889
Author(s):  
Xiaofang Lv ◽  
Yang Liu ◽  
Shidong Zhou ◽  
Bohui Shi ◽  
Kele Yan
Keyword(s):  
Kinetic Model ◽  
Natural Gas ◽  
Gas Hydrates ◽  
Gas Hydrate ◽  
Decomposition Mechanism ◽  
Flow Assurance ◽  
Natural Gas Hydrate ◽  
Oil Emulsion ◽  
Natural Gas Hydrates ◽  
Water In Oil Emulsion

Hydrate slurry decomposition in flow systems is a significant subject that involves flow assurance and development of marine natural gas hydrates.

scholarly journals Investigation on the Secondary Generation of Natural Gas Hydrates in Horizontal Wellbore Caused by Pressure Jump during the Depressurization Development of Hydrate Bearing Layers

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Qingjun Du ◽  
Yongge Liu ◽  
Jian Hou ◽  
Lina Shi ◽  
Wenbin Wang ◽  
...  
Keyword(s):  
Natural Gas ◽  
Gas Hydrates ◽  
Gas Hydrate ◽  
Horizontal Well ◽  
Pressure Jump ◽  
Natural Gas Hydrate ◽  
Water Transportation ◽  
Natural Gas Hydrates ◽  
Environment Temperature ◽  
Wellbore Pressure

When the depressurization development of a hydrate-bearing layer is initiated, the temperature of the near-wellbore formation quickly decreases to near the equilibrium temperature due to the dissociation of natural gas hydrate Therefore, the secondary generation of natural gas hydrates in the wellbore easily occurs if pressure jumps to a high value due to the changes of production rates or shutdown of the well. Though hydrate generation in the process of high-pressure drilling and gas and water transportation has been widely investigated, the secondary generation of natural gas hydrates caused by pressure jump during the depressurization development process is not fully understood. In this study, the multiphase pipe flow of a horizontal well, the Vyniauskas–Bishnoi generation dynamics of natural gas hydrate, and a decomposition dynamics model developed by Kim and Bishnoi are combined to build a set of horizontal well gas–liquid–solid three-phase flow models, which consider the phase transition in the wellbore and distinguished the secondary hydrate generation area in the wellbore under different temperature and pressure conditions. The results show that when the toe-end pressure is 7 MPa and the environment temperature is 6.4°C, the secondary hydrate generation exists in the horizontal section of the horizontal well, and the maximum hydrate flow velocity in the wellbore is 0.044 m3/d. A high toe-end pressure, low environment temperature, and high gas output will result in a greater hydrate generation in the wellbore, and the wellbore pressure will have a remarkable influence on the amount generated and its range.

Thermal Reservoir Simulation Model of Production From Naturally Occurring Gas Hydrate Accumulations

2000 ◽  
Vol 3 (06) ◽  
pp. 559-566 ◽  
Author(s):  
Wim J.A.M. Swinkels ◽  
Rik J.J. Drenth
Keyword(s):  
Natural Gas ◽  
Phase Behavior ◽  
Gas Hydrates ◽  
Gas Hydrate ◽  
Analytical Models ◽  
Thermal Reservoir ◽  
Hydrate Layer ◽  
Hydrocarbon Reservoir ◽  
Natural Gas Hydrates ◽  
Reservoir Simulator

Summary Reservoir behavior of a hydrate-capped gas reservoir is modeled using a three-dimensional thermal reservoir simulator. The model incorporates a description of the phase behavior of the hydrates, heat flow and compaction in the reservoir and the hydrate cap. The model allows the calculation of well productivity, evaluation of well configurations and matching of experimental data. It shows the potentially self-sealing nature of the hydrate cap. Production scenarios were also investigated for production from the solid hydrate cap using horizontal wells and various ways of dissociating the gas hydrates. These investigations show the role of excessive water production and the requirement for water handling facilities. A data acquisition program is needed to obtain reservoir parameters for gas hydrate accumulations. Such parameters include relative phase permeability, heat capacity and thermal conductivity of the hydrate-filled formations, compaction parameters and rate of hydrate formation and decomposition in the reservoir. Introduction Interest in natural gas hydrates is increasing with foreseen requirements in the next century for large volumes of natural gas as a relatively clean hydrocarbon fuel and with increasing exploration and production operation experience in deepwater and Arctic drilling. While progress is being made in identifying and drilling natural gas hydrates, there is also the need to look ahead and develop production concepts for the potentially large deposits of natural gas hydrates and hydrate-capped gas reservoirs. We are now reaching the stage in which some of the simplifying assumptions of analytical models are not sufficient any longer for developing production concepts for natural gas hydrate accumulations. For this reason we have investigated the option of applying a conventional industrial thermal reservoir simulator to model production from natural gas hydrates. Reservoir behavior of free gas trapped under a hydrate seal is to a great extent similar to the behavior of a conventional gas field with the following major differences:thermal effects on the overlying hydrate cap have to be taken into account;potentially large water saturations can build up in the reservoir;relatively low pressures;high formation compressibility can be expected. Use of a thermal compositional reservoir simulator to model the behavior of hydrates and hydrate-capped gas has not been attempted before. We have shown before1 that existing knowledge of phase behavior and thermal reservoir modeling can be fruitfully combined to better understand the behavior of natural gas hydrates in the subsurface. In this paper we will expand on this work and provide further results. After an overview of the model setup, we will first show some results for modeling the depletion of the gas accumulations underlying the hydrate layer. This will be followed by the results for production from the hydrate layer itself, applying heat injection in the formation. Modeling Natural Hydrate Associated Production Attempts to model the behavior of hydrate-capped gas and hydrate reservoirs have been documented by various authors in the literature. Simple energy balance approaches are used by Kuuskraa and Hammershaimb et al.2 Masuda et al.,3 Yousif et al.,4 and Xu and Ruppel5 have presented numerical solutions to analytical models. The first two of these papers do not include thermal effects in their calculations. Reference 5 is specifically aimed at the formation phase of hydrates in the reservoir over geological times, and is less relevant to the production phase. An attempt at explaining the production behavior of a possibly hydrate-capped gas accumulation is described by Collett and Ginsburg.6 The depth and thickness of the hydrate layer under various conditions were described by Holder et al.7 and by Hyndman et al.8 All these approaches apply analytical methods to explain the subsurface occurrence and behavior of natural gas hydrates using various simplifying assumptions. In earlier work1 we have shown that modeling the reservoir behavior of hydrate-capped gas reservoirs with a three-dimensional (3D) thermal hydrocarbon reservoir simulator allows us to account for reservoir aspects, which are disregarded in most analytical models. Such aspects includewell inflow pressure drop and the effects of horizontal and vertical wells in the reservoir;heat transfer between the reservoir fluids and the formation;the geothermal gradient;phase behavior and pressure/volume/temperature (PVT) properties of the reservoir fluids as a fluction of pressure decline;internal architecture and geometry of the reservoir; andreservoir compaction effects. Objective The current study was undertaken to show the feasibility of modeling production behavior of a hydrate-capped gas reservoir in a conventional 3D thermal reservoir simulation model. Objectives of the modeling work include the following.Understand reservoir behavior of natural gas hydrates and hydrate-capped reservoirs. Important aspects of the reservoir thermodynamics are the potential self-preservation capacity of the hydrate cap, the limitation on hydrate decomposition imposed by the thermal conductivity of the rock and the influence of compaction.Confirm material and energy balance analytical calculations.Investigate production options, such as the application of horizontal wells.Calculate well productivity and evaluate well configurations. This study was performed as part of an ongoing project involving other geological and petroleum engineering disciplines. Accounting for Thermal Effects In this study the thermal version of an in-house hydrocarbon reservoir simulator is used.9 We represent the reservoir fluids by a gaseous, a hydrate and an aqueous phase, which are made up of three components, two hydrocarbons and a water component.

scholarly journals Controlled Production of Natural Gas Hydrates in an Experimental Device with an Internal Circulation Circuit

2021 ◽  
Vol 12 (1) ◽  
pp. 312
Author(s):  
Dávid Hečko ◽  
Milan Malcho ◽  
Pavol Mičko ◽  
Nikola Čajová Kantová ◽  
Zuzana Kolková ◽  
...  
Keyword(s):  
Natural Gas ◽  
Gas Hydrates ◽  
Gas Hydrate ◽  
Energy Intensity ◽  
Hydrate Formation ◽  
Experimental Device ◽  
Natural Gas Hydrate ◽  
Hydrocarbon Gases ◽  
Natural Gas Hydrates ◽  
Circulation Circuit

For countries with limited access to conventional hydrocarbon gases, methane hydrates have emerged as a potential energy source. In view of the European Union’s requirements to reduce the energy intensity of technological processes and increase energy security, it appears promising to accumulate natural gas and biomethane in the form of hydrate structures and release them if necessary. Storing gas in this form in an energy-efficient manner creates interest in developing and innovating technologies in this area. Hydrates that form in gas pipelines are generated by a more or less random process and are an undesirable phenomenon in gas transportation. In our case, the process implemented in the proposed experimental device is a controlled process, which can generate hydrates in orders of magnitude shorter times compared to the classical methods of generating natural gas hydrates in autoclaves by saturating water only. The recirculation of gas-saturated water has been shown to be the most significant factor in reducing the energy consumption of natural gas hydrate generation. Not only is the energy intensity of generation reduced, but also its generation time. In this paper, a circuit diagram for an experimental device for natural gas hydrate generation is shown with complete description, principle of operation, and measurement methodology. The natural gas hydrate formation process is analyzed using a mathematical model that correlates well with the measured hydrate formation times. Hydrates may become a current challenge in the future and, once verified, may find applications in various fields of technology or industry.

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