Properties and Potential Benefits of Methane Hydrates - Term Paper Example

Methane Hydrate as an Unconventional Energy Resource That Contribute To Climate Change Table of Contents Abstract 2 Introduction 2 Introduction to Methane Hydrate 3 Definition 4 Properties of Methane Hydrate 5 The Occurrences of Methane Hydrates 6 Tectonic process 6 Accumulation process for the occurrence of methane hydrate 6 The Energy Potential of Methane Hydrates 7 Hydrocarbon 7 Permafrost 8 Effect of Methane Hydrates That Cause Climatic Changes 11 Climatic Perspective 11 List of figures Figure 1 ………………………………………………….. 10 Abstract The Arctic and sediments along the continental margins hold some of the potential forms of energy for the future of the world. Methane hydrates, as they are known are ice-like elements that contain crystalline cages formed by water molecules. However, the possibility that the compound could be destabilized by pressure-temperature conditions that stem from climate change and ultimately lead to high positive carbon-climate responses exist. The compound in its original form is inert, but its exploration have opened up hopes that could bolster the simplification of the world’s carbon footprint. As such, due to the mixed aspect of the compound, an understanding of the potential benefits and the potency of the compound is necessary. The report provides a fundamental overview that enhances the highly uncertain estimates of occurrence of the hydrates. It also explores the response of the compound to changes in the conditions of the environment. Further, the memo provides a highlight on how the current climatic changes could be mitigated by the methane embedded within the hydrate. The use of the methane provides the world an alternative energy source that is not carbon-intensive but rather with zero degrees of emissions. In addition, the report extends to how the exploitation of the dissociating methane hydrates could help in the mitigation of the escape of methane to the atmosphere. Introduction The always increasing demand for energy for sustainable growth and the development of human society ash compelled humankind to seek for renewable and alternative energy forms for the next generation. In meeting the enormous demand of energy, geoscientists are taking initiatives towards the exploration, the exploitation of modern energy resources availed as coalbed methane, and gas hydrates. The naturally occurring gas hydrates have the potential of turning into the future alternative source of energy because of their massive deposits envisaged globally. The memo is a brief introduction of the role of geophysical methodologies in the exploration and exploitation of gas hydrates. Geophysical methods are applied in the assessment of the physical and chemical properties of soil, rocks and groundwater. They are premised on the response to either an array of the electromagnetic spectrum that extends to gamma rays, visible light and other waves or other fields such as gravity and the magnetic field of the earth. The greatest merits of Geophysical methods stems from applying them early in the site characterization process. It happens so because they are mostly nondestructive, less risky and extent to an array of areas spatially and volumetrically and need less time and expenses relative to the usage of monitoring wells. Nonetheless, more skills are required in the interoperation of the data obtained from these techniques. Their indirect aspect tends to create uncertainties that that are solvable by the application of multiple techniques and direct observation. As such, the characterization through the geophysical means is preliminary followed by direct observation via the installation of monitoring wells. Introduction to Methane Hydrate As the demand for sustainable sources of energy continues to rise globally, scientist have been prompted to search for renewable and alternate energy resources. Among the commonly explored forms is coal bed methane in coal seams, gas in shale and gas hydrates deposited on the ocean floors and in permafrost areas in the kind of ice-like structures. Due to their massive deposits envisaged globally, these hydrates could be the alternative, unconventional energy resources. The gas hydrates are white, crystalline, ice-like substances made up of a methane atom that is encapsulated in a cage of water molecules. Though they are often linked to propane, butane, carbon (IV) oxide and hydrogen supplied, the hydrates are typically rich in methane. They are located in the permafrost and at the periphery of the world where the methane concentration goes beyond its solubility limit. Usually, the gas hydrates formation stems from high pressure of between 8 -30 Mpa coupled with low temperature of between 10-20 degree Celsius in shallow sediments. Trapped methane in hydrates and free natural gas below the hydrate-bearing sediments is found in massive volumes. Definition The common name of methane hydrates is catharses. The element is an ice-like compound that holds methane in a crystalline cage-like structure that originates from water molecules, as earlier described. Methane hydrates are unique sedimentary minerals that occur in the continental shell regions and the Arctic regions. Hydrates are chemical or minerals that have water bound within their chemical structure (Best, et al, 2013). As such, methane hydrates are an assemblage of molecular methane moles that are linked within the crystalline lattice formed by the water molecules. The compound is widespread in regions of permafrost such as Arctic and sediments along the continental areas. The continental margins are characterised by high pressure-temperature conditions that are optimal for their formation. In the form, the methane hydrates are potential energy sources of higher magnitudes relative to other known hydrocarbon deposits. As will be discussed in the paper, methane hydrates derive from the trapping of methane and other gaseous compounds in the crystalline structure. The formation occurs in specifically defined regions of stability near the floor of the ocean. Properties of Methane Hydrate Among the geophysical methods, seismic reflection techniques are very vital tools applied in the characterization of the gas hydrates zones. The gas hydrates tend to have firm impacts on seismic reflections due to the high acoustic impedance contrast across the border that separates the overlying gas hydrate and the underlying water full zones. The gas hydrates are arrived at through the mapping of bottom simulating reflectors upon the seismic reflectors. The bottom simulating reflectors are recognized on the grounds of their unique characteristics aspects that mimic the shape of the sea floor. It happens when the BSR follow isotherms that are partially parallel to the morphology of the sea floor ((Best, et al, 2013). It also occurs when they cut across the underlying strata and exhibit voluminous amplitude but opposite polarity to the reflections from the floor of the sea. That rapid and unexpected change in the velocity pattern from high-velocity area linked with the gas hydrates to low velocity water saturated leads to the production of polarity reversal. The resultant velocity configuration creates typical reductions in amplitude in the reflectors above the BSR. The extents to which the amplitudes get diminished rely on the volume of hydrates present. The method of amp The Occurrences of Methane Hydrates Methane hydrate, as earlier described in the introductory part mostly occurs in the Arctic and coastal regions. However, even though the gas is known to be potential sources of energy, and a potential pollutant, knowledge regarding the formation and the occurrence of the compound is vital. Geologists argue for two processes that contribute to the formation of this unique compound. Tectonic process A potentially significant source of methane gas hydrate is mostly located upon an accretionary ridge that stems from tectonic forces. For instance in the coastal regions of Oregon USA, the upper Miocene crust of the Juan de Fuca plate is continuously being subjected underneath the North American plate at the rate of 40-50 mm per year. However, even though methane hydrates are significantly vital sources of energy and contributory to curbing climate change, the geographical distribution and the entire profile of the compound is mostly a mystery. More so, the magnitude of the occurrence of the methane distribution is also unknown. A recent global summit on the occurrence of the compound estimated that the global methane inventory is probably in the range of 1000-10000 Gtc (Volker, et al, 2009). Accumulation process for the occurrence of methane hydrate The uncertainty extends to the fraction of hydrates that could be available as an energy source and the segment that could turn vulnerable to anthropogenic changes in the climate. The uncertainty stems from the limitations of the available seismic and electromagnetic methodologies to reliably classify the quantities and the attributes of the accumulations of hydrates. Other than the occurrence of the compound in the Arctic region, the deposits of methane hydrate are found in the continental shelf areas and other marine sediments because of the accumulation (Best, et al, 2013). As earlier pointed out, methane hydrates are an assemblage of molecular methane molecules bound within a crystal lattice of water molecules. The methane that eventually embeds as a hydrated compound stems from microorganisms that produce methane as byproducts. The rate and the volume of the accumulation of the hydrate rely on the supply of methane. The formation of clathrate happens in coarse sediments as opposed to fine-grained sediments. As such, sediment lithology plays a vital role in the determination of where the hydrates beds form. The consequence is due in large part to coarse-grained sediments that have higher permeability degrees relative to fine-grained pelagic clays. As the upwelling methane gas reaches the HSZ, the gas dissolves within the pore spaces of grain sediments. Within the HSZ, the gas exists in three phases among them is the hydrate form (Best, et al, 2013). The Energy Potential of Methane Hydrates Hydrocarbon Natural gas that is mostly methane is known globally as a clam burning compound and a vital bridge fuel to a future where renewable sources of energy are more needed. Methane hydrate, which is composed, of the molecules of natural gas embed in an ice-like cage of the molecules of water. The compound presents an enormous source of methane gas for the world. Latest explorations of oil and gas in Arctic and marine environs have discovered that the substance is a natural storehouse of carbon and a prospective source of energy (Volker, et al, 2009). The science of methane hydrate has drastically advanced such that commercial-scale production of natural gas from the deposits of the compound is growing viable at each step of exploration. The global volume of methane held within methane hydrate is enormous. Most experts always quote that the global methane hydrate resource is 20,000 trillion cubic meters. Nevertheless, only a relatively less volume of the compound could be harvested as a source of energy. If the advancement in gas exploration techniques could be applied economically to the creation of the compound as a potential source of natural gas, the world would significantly cut its reliance on oil and gas. Of importance is the fact that nations that import vast amounts of oil could be saved more funds and hence become more self-sufficient (Volker, et al, 2009).. Permafrost However, the attributes of hydrate deposits vary broadly and coupled with these traits are the challenges in the technological arena. Methane hydrates from onshore sub-permafrost that are exploited through quasi-conventional technologies continue to be the low hanging fruit. To enhance the economies of the extraction of hydrates requires a leverage of the existing infrastructure. Even though extensions of the prevailing technologies are applicable to the exploitation of ocean hydrates, it is worth noting that extended exploitation requires a model shift in the techniques employed in the production. The paradigm shift is necessary since the bulk of the hydrates is embedded in deposits with very low concentrates of hydrate. Figure 1: Methane hydrates recovery onshore from below the permafrost in the Arctic and offshore from the sediment of the continental margin. The layer in the lower right corner is the appropriate temperature and pressure conditions for the formation of methane hydrates. (Volker Key) source, (Volker, et al, 2009). As provided in the figure above, the recovery process of the hydrates of the gas from the Arctic permafrost requires dedicated research and developments beyond the scope of current exploitation. Gas hydrate exploitation derives from national policies and the scarcity of alternative forms of energy. As such countries with an enormous demand based on energies such as Chaina and the US are at the vanguard of the exploration of hydrate energy. Consequently, predictions are that large-scale production of the gas would likely begin in 2020 before gradually spreading to other regions (Volker, et al, 2009). The methane hydrates can turn methane gas the chief energy resource in the medium term and bridge the gap to a carbon-free global environment. However, reports argue that for the realization of the largest potential, the capture of carbon and storage is needed under any significant stabilization of carbon dioxide. For instance, during the extraction and burning of methane in situ, the possibility of carbon dioxide hydrate being deposited simultaneously is possible. With this challenges, the fact that energy resources from methane hydrate could be of the same degree as coal, substantial extractions might contribute to anthropogenic climatic changes without the capture of carbon (Zuo, et., 2011). Currently, the world’s energy system is reliant on hydrocarbons. However, the widely applicable sources are natural gas and oil, of which over 80 percent of the modern global energy supply traces to fossil fuels. Nevertheless, de-carbonization of the supplies of energy continues to be a historical evolutionary method. Typical fuels such as biomass with relatively high carbon content were replaced by coal that later on got substituted by oil. The move saw further reductions in the intensity of the primary forms of energy. With this dynamics embed on the inherent inertia of technological change, a total shift to the use of non-carbon primary sources is not imminent in the near future (Dich, et, al., 2012). Experts argue that global emissions would have to peak in the next twenty years followed by a drop to zero for there to be a limit in the global mean temperature. The resultant would be a massive energy gap between the demand of energy and the expected abetments in emissions necessary for the reduction of human interface with nature. Of interest, however, is that presents an opportunity for the methane hydrates to be seen as vital energy source. They are anticipated to span the breach between carbon-intensive fossil fuels and non-carbonated forms (Dich, et, al., 2012) Experts claim that as little as one thousand parts of the world’s methane hydrates deposits are sufficient to cater for the current energy demands. Nonetheless, the transition is only possible provided technological changes, efficient knowledge of geological forms and shifts in economies from the reliance on fossil fuels occur. Effect of Methane Hydrates That Cause Climatic Changes Climatic Perspective Due its lower proportion in the atmosphere relative to carbon dioxide, the absorption bands of methane have much less saturation and as such the gas is a very potent greenhouse gas. Methane hydrate is intrinsically vulnerable to the atmosphere such that the only factor that can hold it at high force is the mass of the mud on top of it along the coastal regions. Relatively fewer degrees of warming in the depths of the ocean can influence the stability of the hydrate. However, it is a fact that the temperatures at the bottom of the ocean tend to respond to fluctuations in the climate of the surface. Thus, concerns abound that changes in the climate can trigger substantial methane releases from the hydrates and ultimately lead to active positive-carbon responses. The release of methane arising from hydrate destabilization result from holes in the sediment surface of the ocean and submarine sublimes. Estimates show that the amounts released is every event are constrained to approximately 1-56 Gets. The emissions create increased radioactive forcing of beyond 0.2 W m provided that all of the released methane reach the atmosphere. The forms of methane released that can course climate change are that with a chronic nature. Most of the changes in the temperature of the ocean floor have significant impacts on the stability of hydrates zones and ultimately on the equilibrium inventory of the inventory of the methane hydrate. Nevertheless, the long ventilation times of the depth of the ocean coupled with the slow propagation of the temperature signal within the sediment column. Furthermore, the segment of the gas from the depth of the sea reaches the atmosphere is unknown and reliant on the propulsion mechanism. The oxidation lifetime of the gas dissolved in ocean water is approximately 50 years and as such, it would probably reach the atmosphere as carbon dioxide gas. However, an exception from the long response periods is the Arctic hydrates since the stability regions only reach 200 meters below the surface. Within the shallow polar regions the accumulations of methane, hydrate is poorly quantified implying that efficient inventories are vital in the estimation of the release of methane from these sources. In addition, robust warming beyond the moderate makes the Arctic hydrates specifically more vulnerable to changes in the climate. The vulnerability is more likely to become a safety issue in typical oil and gas exploration as more voices cry for the commencement of production. The continued calls for the commencement of production are partially attributed to the rapid melting of sea ice. Of importance, however, is that, provided the production is carefully carried out, the exploitation of the dissociating methane hydrates has the potential of mitigating the escape of methane to the atmosphere. The case is unique to gas hydrates and sets them aside from other unconventional natural gas occurrences. Conclusions Methane hydrates are vital minerals found in marine sediment beds on continental shelves and arctic reigns globally. The distinct chemistry of gaseous catharses enables even the most unreactive gases such as inert gases to participate in the alteration of the chemical properties of compounds in a perceptible manner. Since the hydrate beds are together by weak van der Waals forces, the inventories of methane hydrates are very unstable and can easily release huge volumes of methane gas to the ocean and the atmosphere. However, reports are that the reservoirs of the methane hydrates represent key carbon reservoirs that can easily escape from their clathrate cage easily. The escape of methane from the seabed has continuously been blamed for global warming. On the positive side is the argument that the methane held in this hydrates has massive potential of releasing vast amounts of zero-emissions relative to the conventional carbon intensive fuels such as oil. If well managed and well explored, the gas could help the world reduce its carbon footprint in the future and make the world more environmentally friendly. The long-run effect would be a reduction in climate change and global warming. Despite these merits, the potential for this untapped source of energy is not without significant risks. Concerns are about whether the use of methane hydrates, as natural forms, are safe or relatively cheaper. As much, the report recommends that more research and engineering is needed to study on the drawbacks associated with methane hydrates prior to any significant large-scale extraction. References Best, A. I., Priest, J. A., Clayton, C. R., & Rees, E. V. (2013). The effect of methane hydrate morphology and water saturation on seismic wave attenuation in sand under shallow sub-seafloor conditions. Earth and Planetary Science Letters, 368, 78-87 Dich, A., Grimsley, K., Koufos, D., Sarasin, T., Rodas, M., & Humi, M. (2012) Alternative and Renewable Energy Interactive Qualifying Project Worcester Polytechnic Institute Produced By Lonero, A. (2008). How Are Methane Hydrates Formed, Preserved, and Released. Geology, 340, 53-58 Volker Krey et al 2009. Gas hydrates: entrance to a methane age or climate threat?. Environ. Res. Letters Zuo, L., Sun, L., & You, C. (2011). Latest progress in numerical simulations on multiphase flow and thermodynamics in production of natural gas from gas hydrate reservoir. Frontiers of Energy and Power Engineering in China, 3(2), 152-159. doi:http://dx.doi.org/10.1007/s11708-009-0017- Read More