Gas Hydrates Research Papers - Academia.edu (original) (raw)

Iran has the second largest natural gas reserves in the world. Therefore, it is heavily investing in expanding its gas production, processing, and transportation capacity. The main objectives include: Promoting the usage of natural gas as... more

Iran has the second largest natural gas reserves in the world. Therefore, it is heavily investing in expanding its gas production, processing, and transportation capacity. The main objectives include: Promoting the usage of natural gas as a low carbon fuel and primary source of energy to reduce the domestic demand on oil. Using natural gas for EOR and pressure maintenance in mature oil fields. Exporting natural gas and its products. However, expanding the natural gas network demands a more comprehensive research on potential gas hydrate problems and mitigation techniques. In this communication, we give a review on typical gas hydrate problems in the Iranian production and gas transportation facilities and networks and various prevention techniques. We also present details of construction and commissioning of a hydrate test rig at the Research Institute of Petroleum Industry (RIPI) of the National Iranian Oil Company (NIOC). Finally, we present experimental data on the hydrate stability zone of some Iranian natural gases. We conclude that further national and international research and investment is beneficial to minimize gas hydrate risks in the Iranian Gas Industries, as well as exploring positive applications of gas hydrates with respect to specific conditions in Iran.

Methane gas hydrate is an interesting research topic for its potential as an alternative energy source as a mechanism for possible reducing emissions of greenhouse gases. The effort to find alternatives to traditional hydrocarbons such as... more

Methane gas hydrate is an interesting research topic for its potential as an alternative energy source as a mechanism for possible reducing emissions of greenhouse gases. The effort to find alternatives to traditional hydrocarbons such as oil, coal and natural gas is increasing, either because they are polluting and / or because its extraction has become more difficult. A possible replacement that is gaining attention is methane hydrate, which is found in huge quantities in permafrost, the frozen soil of the Arctic, deep water. Known as "ice that burns" Methane hydrate consists of ice crystals with gas trapped inside. These crystals are formed from a combination of low temperature and high pressure. Gas Hydrate reserves are huge, and the estimate is that there is more energy stored in methane hydrates than the sum of all oil, gas and coal in the world. Japan, Canada, United States, India, among others, have research and international partnerships programs that focus not only on the characterization and quantification, but also the development of new technologies of commercial methane production. This document is a bibliographical analysis on articles and found theses, and an analysis of the viability of production of gas hydrate as alternative energy versus the possibility of exploitation of worsening climate change in the world. Keywords: Gas Hydrate; Oil Industry; Alternative Energy

Oil and Gas Hydrate plug dissociation in subsea pipelines is a challenging problem in oil and gas transport systems as limited options are available for remediation. Key concerns include technical, operational deferment and safety... more

Oil and Gas Hydrate plug dissociation in subsea pipelines is a challenging problem in oil and gas transport systems as limited options are available for remediation. Key concerns include technical, operational deferment and safety hazards that are associated with hydrate plug dissociation in oil and gas pipelines. This paper presents a comprehensive review of the physics of hydrate plugs remediation including a compilation of dissociation models, experimental work performed to date, and a detailed analysis on the problem of gas hydrate from a flow assurance perspective. Depressurization methods are critically reviewed, with influence of temperature, pressure, velocity and hydrate plug properties discussed with detail. Outstanding research questions for hydrate plug dissociation highlighted.

As a huge reserve for potential energy, natural gas hydrates (NGHs) are attracting increasingly extra attentions, and a series of researches on gas recovery from NGHs sediments have been carried out. But the slow formation and... more

As a huge reserve for potential energy, natural gas hydrates (NGHs) are attracting increasingly extra attentions, and a series of researches on gas recovery from NGHs sediments have been carried out. But the slow formation and dissociation kinetics of NGHs is a major bottleneck in the applications of NGHs technology. Previous studies have shown that nanobubbles, which formed from melt hydrates, have significant promotion effects on dissociation and reformation dynamics of gas hydrates. Nanobubbles can persist for a long time in liquids, disaccording with the standpoint of classical thermodynamic theories, thus they can participate in the hydrate process. Based on different types of hydrate systems (gas + water, gas +water +inhibitors/promoters, gas + water + hydrophilic/hydrophobic surface), the effects of nanobubble evolution on nucleation, dissociation, reformation process and "memory effect" of gas hydrates are discussed in this paper. Researches on the nanobubbles in hydrate process are also summarized and prospected in this study.

La formation d'Hydrates est un sérieux problème que rencontre l'industrie pétrolière surtout dans les conduites de gaz, que se soit en on-shore ou off-shore. Dans ce mémoire nous avons étudié les conditions de formation de ces hydrates... more

La formation d'Hydrates est un sérieux problème que rencontre l'industrie pétrolière surtout dans les conduites de gaz, que se soit en on-shore ou off-shore. Dans ce mémoire nous avons étudié les conditions de formation de ces hydrates dans les pipes de gaz desservants les puits gas-lifté; ensuite nous avons comparé via PIPESIM l’efficacité de plusieurs inhibiteurs et choisi le meilleur.

Tight gas is an important unconventional gas resource. It is also a basin centered gas reservoir which is associated with existing oilfields or bypassed zones and characterized by low in situ permeability of less than 0.6 mili Darcy. This... more

Tight gas is an important unconventional gas resource. It is also a basin centered gas reservoir which is associated with existing oilfields or bypassed zones and characterized by low in situ permeability of less than 0.6 mili Darcy. This evaluation initially started at San Juan basin in USA. There are about 40,000 tight gas wells producing from 1600 reservoirs in 900 fields whose estimated capacity is 3400 tcf. In India, the Cambay field holds about 413 bcf. amount of tight gas reserves. The layers of Tight Gas are attributed to commingled production and they are often layered and complex. Since the permeability is quite low, the reserves cannot be obtained profitably by vertical wells. As a result mostly horizontal wells and S-shaped wells are used for production of tight gas. Processes like Hydraulic Fracturing and Acidization are used to stimulate the well for better recovery. This technical paper aims at evaluation of tight gas reservoir in order to ameliorate the exploitation through different processes like material balance, volumetric method, transient pressure test, productivity index test and decline curve method along with the modern methods of interpretation of concentration pattern such as detailed Petrography by implementing XRD(X-ray diffraction) and SEM (Scanning Electron Microscope). Elemental Capture Spectroscopy along with Spectral Gamma Logging helps in detecting the distribution within wells. Tight Gas offers maximum recovery rate of 20%.

n this experimental study, the phase boundary behaviour of CO2 hydrate is reported in the presence of 1, 5, and 10 wt% of three aqueous ammonium based ionic liquids (AILs) solutions. The T-cycle technique is used to measure the hydrate... more

n this experimental study, the phase boundary behaviour of CO2 hydrate is reported in the presence of 1, 5, and 10 wt% of three aqueous ammonium based ionic liquids (AILs) solutions. The T-cycle technique is used to measure the hydrate equilibrium conditions of AILs + CO2 + H2O hydrate systems within the ranges of 274 – 283 K and 1.80 – 4.20 MPa. All studied AILs inhibited CO2 hydrate with the inhibition effect increasing with AILs concentration. The 10 wt%, TEAOH showed the highest inhibition effect with an average suppression temperature (∆Ŧ) of 1.7 K, followed by TMACl (∆Ŧ = 1.6 K) and then TPrAOH (∆Ŧ = 1.2 K). Furthermore, COSMO-RS analysis is performed to understand the molecular level inhibition mechanism of AILs. In addition, the enthalpies of hydrate dissociation for all studied systems are also determined. The calculated hydrate dissociation enthalpies revealed that all the studied AILs show insignificant participation in CO2 hydrate cage formation at all concentrations, hence, do not form semi-clathrate hydrates.

Empty spaces are abhorred by nature, that immediately rushes in to fill the void. Humans have learnt pretty well how to make ordered empty nanocontainers, and to get useful products out of them. When such an order is imparted to... more

Empty spaces are abhorred by nature, that immediately rushes in to fill the void. Humans have learnt pretty well how to make ordered empty nanocontainers, and to get useful products out of them. When such an order is imparted to molecules, new properties may appear,often yielding advanced applications. This review illustrates how the organized void space inherently present in various materials – zeolites, mesoporous silica/organosilica, and metal organic frameworks (MOF), for example, can be exploited to create confined, organized, and self-assembled supramolecular structures of low-dimensionality. Features of the confining matrices relevant to organization are presented with special focus on molecular-level aspects. Selected examples of confined supramolecular assemblies-from small molecules to quantum dots or luminescent species-are aimed to show the complexity and potential of this approach. Natural confinement (minerals) and hyperconfinement (high pressure) provide further opportunities to understand and master the atomistic-level-interactions governing supramolecular organization under nanospace restrictions.

A thermodynamic model to predict three phase (L-H-V and I-H-V) equilibria of gas hydrates is presented. In this model we have employed a fugacity based approach where the hydrate phase is modeled using van der Waals-Platteeuw solid... more

A thermodynamic model to predict three phase (L-H-V and I-H-V) equilibria of gas hydrates is presented. In this model we have employed a fugacity based approach where the hydrate phase is modeled using van der Waals-Platteeuw solid solution theory and the liquid phase activity coefficients are determined from the modified UNIFAC method. For the vapour phase fugacity calculations we have investigated three equations of state (EOS): Peng-Robinson-Stryjek-Vera (PRSV), Patel-Teja (PT) and Soave-Redlich-Kwong (SRK). This model employs only parameters reported in the literature. The coexistence pressures predicted by our model for the sI hydrates of methane, carbon dioxide and ethane are in reasonable agreement with experiments, whereas our model overestimates the coexistence pressures for the sII clathrates of nitrogen and propane. The predicted cage occupancies are found to increase with increasing temperature in the L-H-V equilibria. For I-H-V equilibria the cage occupancy is observed to decrease with temperature. We have also estimated the solubility of each guest in the liquid phase (for L-H-V equilibria) using the Henry's law. The solubilities predicted using all three EOS are in good agreement for all guest molecules, with the exception of nitrogen where at relatively higher temperatures the estimates from the PRSV EOS are noticeably lower than the corresponding predictions from the PT and SRK EOS.

The relation between anthropogenic emissions of CO2 and its increased levels in the atmosphere with global warming and climate change has been well established and accepted. Major portion of carbon dioxide released to the atmosphere,... more

The relation between anthropogenic emissions of CO2 and its increased levels in the atmosphere with global warming and climate change has been well established and accepted. Major portion of carbon dioxide released to the atmosphere, originates from combustion of fossil fuels. Integrated gasification combined cycle (IGCC) offers a promising fossil fuel technology considered as a clean coal-based process for power

We report on a detailed analysis of amplitude anomalies in three-dimensional (3D) seismic reflection data and their surrounding strata in the shallow subsurface of the northern part of the Indus Submarine Fan, Arabian Sea. Our analysis... more

We report on a detailed analysis of amplitude anomalies in three-dimensional (3D) seismic reflection data and their surrounding strata in the shallow subsurface of the northern part of the Indus Submarine Fan, Arabian Sea. Our analysis reveals the presence of distributary lobe complexes and a relict fluid migration system, including a buried mud volcano, linked to contractional anticlines overlying deep-seated strike-slip faults buried below the Indus slope. Building on a regional tectonic and stratigraphic framework, we have used a 3D seismic survey to map in detail the occurrence of high-amplitude anomalies in the shallow subsurface. We link these to gas hydrate and free gas accumulations hosted within distal distributary lobes deposited on the Indus slope and supplied by underlying focused fluid flow system along a fault zone. Our results suggest that the seismic amplitude anomalies may be classified as a weak ‘‘bottom-simulating reflection’’ (BSR) formed during a paleofluid flow event in the northern Indus Fan (~5–1.8 Ma). Present-day fluid influx is low.

The distinction between conventional and unconventional hydrocarbon accumulations depends on whether oil or gas are hosted within a well-defined trap and whether they can be produced economically by wells. The unconventional oil and gas... more

The distinction between conventional and unconventional hydrocarbon accumulations depends on whether oil or gas are hosted within a well-defined trap and whether they can be produced economically by wells. The unconventional oil and gas resources cannot be extracted economically by using conventional methods and technologies, while the conventional accumulations refer to technically and economically recoverable hydrocarbons. The unconventional accumulations are characterized by large resources but poor reservoir properties. Conventional hydrocarbons only account for less than 20% of the world’s fossil fuel resources, whereas unconventional hydrocarbons account for at least 80%. On the Romanian territory, 10 petroleum basins with different hydrocarbon richness have been identified: Moesian Platform, Transylvanian Basin, Eastern part of Pannonian Basin, Eastern Carpathians Flysch, Moldavian Platform, Carpathian Foredeep, Schythian Platform, Maramures Basin, North-Dobrogean Promontory and the Romanian shelf of the Black Sea. In these basins more than 18 petroleum systems have been identified. Almost all these petroleum basins contain unconventional hydrocarbon resources like shale gas, shale oil, heavy oil, tar sands, tight sands gas, gas hydrates and coal bed methane (CBM).

In this study one seismic section offshore Chiloé Island was analyzed to better define the seismic character of the hydrate-bearing sediments. The velocity analysis was used to estimate the gas-phase concentration and relate it to the... more

In this study one seismic section offshore Chiloé Island was analyzed to better define the seismic character of the hydrate-bearing sediments. The velocity analysis was used to estimate the gas-phase concentration and relate it to the geological features. The velocity model allowed us to recognize two important layers that characterize hydrate-and free gas-bearing sediments above and below the BSR respectively: one located above the BSR, characterized by high velocity (1,800-2,200 m/s) and a second one, below the BSR, characterized by low velocity (1,600-1,700 m/s). A weak ref lector at about 100 m below the BSR marks the base of the second layer. AVO analysis and offset stack sections confirming that the reflector interpreted as BGR is related to free gas presence in the pore space. The velocity field is affected by lateral variation, showing maximum (above the BSR) and minimum (below the BSR) values in the sector. Here, the highest gas hydrate and free gas concentrations were calculated, obtaining 9.5% and 0.5% of total volume respectively. A variable BSR depth (from 300 to 600 mbsf) can be justified supposing a variable geothermal gradient (from 25 to 45 °C/km). RESUMEN. Estimación de hidratos de metano y gas libre mediante análisis sísmico frente a Chiloé (Chile). Este estudio analiza una sección sísmica marina frente a Chiloé, con el objeto de definir a través de las propiedades sísmicas las características de los sedimentos que contienen hidratos de metano. Mediante el análisis de la velocidad sísmica, es estimada la concentración de la fase-gas y su relación con estructuras geológicas. El modelo de velocidad permite reconocer dos capas importantes, una sobre el BSR de alta velocidad (1,800-2,200 m/s) asociada a hidrato y otra por debajo del BSR de baja velocidad (1,600-1,700 m/s) relacionada con la fase-gas libre. Un débil ref lector, ubicado aproximadamente a 100 m por debajo del BSR, marca la base de la segunda capa. Un análisis de AVO y secciones apiladas por offset permiten confirmar que este corresponde al BGR y que estaría relacionado con la presencia de gas libre. La velocidad sísmica varía lateralmente, alcanzando un valor máximo (sobre el BSR) y un mínimo (bajo el BSR) en el área. Las más altas concentraciones de hidrato y gas libre son alcanzadas en esta área (9,5% y 0,5% del volumen total respectivamente). El aumento en la profundidad del BSR (desde 300 a 600 mbsf) es justificado suponiendo un gradiente geotérmico variable (desde 25 a 45 °C/km).

Abstract- Carbon dioxide emission into the atmosphere from the major point sources such as coal fired power plants, steel plants, cement industries triggered studies on its green house effects. Mineral carbonation is an option for storage... more

Abstract- Carbon dioxide emission into the atmosphere from
the major point sources such as coal fired power plants, steel
plants, cement industries triggered studies on its green house
effects. Mineral carbonation is an option for storage of carbon
dioxide in industrial waste materials by converting it into
carbonates similar to the end products of natural weathering
processes. Present study deals with carbonation of steel slag for
carbon dioxide storage and also utilization of the converted
carbonates in structures for shore protection. Blast furnace slag
and Linz‐Donawitz converter slag are subjected to high pressure
(>20 bar) and temperatures above 60°C in presence of carbon
dioxide in a reactor to convert into carbonate. Laboratory
experiments showed encouraging results with a 50% conversion
of less than 75μm sized slag into carbonate. Converted
carbonates are proposed to be utilized in the development of
artificial reefs and the laboratory studies on the behavior of the
material in sea water are conducted. Details of the carbonation of
steel slag and preparation of structures for artificial reef
development are discussed in the paper.

In this experimental work, the phase boundaries of TMAOH + H O + CH4 and TMAOH + H2O + CO2 hydrates are measured at different concentrations of aqueous TMAOH solution. The temperature cycle (T-cycle) method is applied to measure the... more

In this experimental work, the phase boundaries of TMAOH + H O + CH4 and TMAOH + H2O + CO2 hydrates are measured at different concentrations of aqueous TMAOH solution. The temperature cycle (T-cycle) method is applied to measure the hydrate equilibrium temperature of TMAOH + H2O + CH4 and TMAOH + H2O + CO2 systems within the ranges of 3.5e8.0 MPa and 1.8e4.2 MPa, respectively. Results reveal that TMAOH acts as a thermodynamic inhibitor for both gases. In the presence of 10 wt% of TMAOH, the inhibition effect appears to be very substantial for CO 2 with an average suppression temperature (DŦ) of 2.24 K. An ample inhibition influence is observed for CH 4 hydrate at 10 wt% with DŦ of 1.52 K. The inhibition effect of TMAOH is observed to increase with increasing TMAOH concentration. Confirmed via COSMO-RS analysis, the TMAOH inhibition effect is due to its hydrogen bonding affinity for water molecules. Furthermore, the calculated hydrate dissociation enthalpies in both systems revealed that TMAOH does not participate in the hydrate crystalline structure.

Gas hydrates gained a remarkable attention as an unconventional energy resource recently. In order to interpret gas hydrates (part of fluid) and free gas saturated zone accurately, it is essential to implement new technique related to... more

Gas hydrates gained a remarkable attention as an unconventional energy resource recently. In order to interpret gas hydrates (part of fluid) and free gas saturated zone accurately, it is essential to implement new technique related to seismic attenuation and velocity dispersion. P wave atten-uation and velocity dispersion in porous media made promising imprints for exploration of gas hydrates. The most prominent phenomenon for attenuation and velocity dispersion in porous media is wave induced fluid flow in which wave inhomogeneities are larger than pore size but smaller than wavelength. Numerical simulation technique is applied to analyze frequency dependent velocity dispersion and attenuation in gas hydrates and free gas layer in Makran offshore of Pakistan. Homogeneous and patchy distribution patterns of gas hydrates and free gas within pore spaces of host sediments at lower and higher frequency regime are considered. It is noted that the attenuation and velocity dispersion increase with the increase in gas hydrates saturation. The maximum attenuation is observed at 66% saturation of gas hydrates in the area under investigation. However, in case of water and gas mixture the maximum attenuation and velocity dispersion occur at low gas saturation (~15%). Therefore, based on our numerical simulation, velocity dispersion and attenuation can be used as seismic attributes to differentiate various gas saturations and gas hydrates saturation for Makran offshore area of Pakistan.