Gas Hydrate Development Research Articles

A mass transfer model for hydrate formation in bubbly flow considering bubble-bubble interactions and bubble-hydrate particle interactions

Methane hydrate formation in bubbly flow widely exists in development of oil, gas and natural gas hydrate in deep-water environment, as an important flow assurance problem. The hydrate formation in swarms is a mass transfer process and does not simply equal to the weighted sum of hydrate formation on single moving bubble. The bubble-bubble interactions and the bubble-hydrate particle interactions in bubbly flow will promote the mass transfer coefficient during hydrate formation and accelerate hydrate formation in bubbly flow. Meanwhile, series of experiments are performed to investigate characteristics of hydrate formation in bubbly flow under Re from 15,000 to 22,000. The hydrate formation rate and the mass transfer coefficient increase with the fluid velocity increases. The mass transfer coefficient ascends exponentially with time because the increase of quantities of hydrate particles in flow loop create more interactions between bubbles and hydrate particles. The increase of mass transfer coefficient further compensates the reduction of hydrate formation rate induced by subcooling temperature decreasing in experiments. A mass transfer hydrate formation model is developed to depict hydrate formation in bubbly flow including the bubble-bubble interaction factor and the bubble-hydrate particle interaction factor and reaches a good agreement with experimental data.

Experimental investigation into formation/dissociation characteristics of methane hydrate in consolidated sediments with resistance measurement

Natural gas hydrates (NGHs) are considered as a powerful potential energy resource. In this work, an experimental system containing a digital electrical bridge for resistance measurement was developed to gain an improved understanding of the formation/dissociation characteristics of NGHs in consolidated sediments. Using the apparatus, a dynamic methane hydrate formation method for sandstone cores was developed that can maintain a constant gas flow in the core during the methane hydrate formation process. As opposed to the traditional method that maintains a constant pressure in the core, higher resistance, permeability, and hydrate saturation for the core were obtained following methane hydrate formation equilibrium by using the proposed method. In order to investigate the methane hydrate formation characteristics in sandstone cores, the influences of core permeability, temperature, initial water saturation, and salinity on the resistance and hydrate saturation of two cores were analyzed in detail. The experimental results demonstrate that a relative lower temperature and higher initial water saturation in the core correspond to a higher hydrate saturation and water-to-hydrate conversation ratio. In the process of methane production from continent hydrate, the water output from the core with methane extraction was experimentally measured for the first time. It was found that, owing to the existence of free gas in the core holder, both the core resistance and methane production rate were not changed linearly with time. The methane production amount increased with an increase in initial water saturation, decrease in production pressure, or increase in pore volume in the core. It was demonstrated that water output is not a serious problem in the development of continental natural gas hydrate.

Gas production peaks in China: Research and strategic proposals

The peaks of natural gas production are of great significance to the planning of national energy strategy, the coordinated development of natural gas industry chain and the investment decision-making for oil and gas companies. Therefore, based on natural gas geological and development characteristics, the production peaks of conventional gas (including tight gas), CBM and shale gas in China have been systematically analyzed and forecasted using multiple methods. The following conclusions are drawn: first, the cumulative gas production in China will reach 280–330 bcm by 2035 and 330–410 bcm by 2050; second, the conventional gas production peaks will be easily predicable during the forecast period, while the peaks of CBM and shale gas production need to be further forecasted and tracked continuously; third, with the possible breakthrough of gas hydrate exploration and development being considered, gas production in China has a great potential and bright future. In order to achieve a strategic goal of energy transformation and conservation and to guarantee a safe and stable gas supply, a timely profound analysis and study will be necessary on the international political, economic and energy development situation for a global gas strategic layout. In view of this, based on the analysis of domestic natural gas supply and demand situation, the following proposals are put forward: to speed up the domestic tapping and commercial production of those deep-strata, deep-water and unconventional gas resources to consolidate the dominant position of domestic natural gas supply; to attach great importance to a strategic layout of overseas gas resources utilization and to adopt various ways to ensure the security of domestic gas market; to accelerate the evaluation of gas hydrate development in order to enlarge and consolidate the gas resource basis; and to strengthen a dynamic forecast on the peaks of gas production in order to continuously enhance the soft power in international competition.

Effect of hydrate on permeability in porous media: Pore-scale micro-simulation

The permeability variation caused by hydrate dissociation will affect the further exploitation of hydrate resources during the development of natural gas hydrate. To study the effect of hydrate on seepage characteristics in hydrate-bearing sediments, the micro-flow simulation was carried out by the lattice Boltzmann method. The effect of factors related to the pore-scale distribution of mineral particle and hydrate on permeability variation was analyzed in the two-dimensional porous media. Results show that the mineral particles arrangement has no effect on permeability variation for the two-dimensional homogeneous porous media, the permeability variation is sensitive to the hydrate-formation habit and hydrate-distribution morphology in the pore center. The concept of “control seepage channel” is proposed through comparative analysis of velocity field distribution. It controls the change characteristics of permeability. Based on the control seepage channel size and the control seepage channel tortuosity, a new model is presented to measure the permeability in porous media with gas hydrate. Considering two hydrate-formation habits: grain-coating and pore-filling, the relationships between relative permeability and hydrate saturation are proposed to describe permeability variation. The relationship of pore-filling case agrees well with the experimental results. It shows that hydrate grows mainly in the pore center under the experimental conditions.

Shielded Development of Marine Bottom Gas Hydrates by Fracking a Layer

The concept and a new method for the shielded development of bottom gas hydrates have been proposed, the technological phases and constructive elements of their implementation have been substantiated. The research provides for the realization of the idea suggesting the simultaneous dissociation of the vast areas of a gas hydrate deposit, management of the targeted process of the penetration of methane recovered from gas hydrates into water space and its accumulation under the extensive gas-collecting shield wherefrom it is removed by bottom pipe transportation facilities. To do hydraulic fracturing, a well is drilled into the plane of the junction of the surface of a gas hydrate deposit and the rocks of a roof, the open system of fissures in the rocks of a roof is made through which produced gas is released to a gas-collecting blanket in a water.

Natural gas hydrate exploitation by CO2/H2 continuous Injection-Production mode

CO2 replacement is considered as a promising method for the simultaneous development of natural gas hydrate and CO2 sequestration. The addition of small molecular gases, such as N2 and H2, into the injected gas can increase the gas recovery ratio and prevent CO2 liquefaction. Based on previous studies, this work presents methane hydrate exploitation using the CO2/H2 continuous injection-production mode. The mechanism combines gas sweep with CH4/CO2 replacement. A series of experiments were carried out to optimize the injected gas composition and flow rate, which have a significant effect on the rate of CH4 hydrate decomposition, amount of CO2 sequestration, and cost. The compositions of the injected gases had little effect on the recovery rate when a relatively higher flow rate was employed. A balance between CH4 production and CO2 sequestration was established when the CO2 mole fraction was slightly <74%, and the temperature of the reservoir did not decline throughout the whole process. The injection rate affected both the displacement efficiency and the production cost. Moreover, through these experiments, we discovered a more economically feasible and productive measure for regulating the injection rate.

Expanding of spheres the application of borehole hydro-production technology to develop deposits of non-traditional hydrocarbons

The reserves of oceanic hydrates of methane and natural bitumen in times exceed the stocks of traditional oil and gas. The purpose is the analysis of the adaptation possibility of borehole mining technology for the development of bituminous sands deposits and marine gas hydrates was the purpose of the study. The variants of the HBM technology adaptation for the development of bituminous sands and gas hydrates deposits are proposed. The method of extracting gas hydrates based on HBM technology involves them removal without the energy consumption for phase transition. The main advantages of the development of bituminous sands deposits on the basis of HBM technology are: the possibility them extraction in the range of depths 75 – 200 m, the potential high rate of bitumen extraction, the separation of bitumen from the rock in production, the minimum impact on the environment, the possibility of conducting extraction of natural bitumen in areas covered with water.

Shielded development of bottom gas hydrates

Автори вдячні авторам колективної монографії “Газогідрати. Гідратоутворення та основи розробки газових гідратів” (зокрема В.І. Бондаренку, О.Ю. Витязю, М.Л. Зоценку, К.С. Сай, Е.О. Максимовій), яка надихнула їх на пошуки нових шляхів освоєння газогідратних родовищ.

Focus on the Development of Natural Gas Hydrate in China

Natural gas hydrate, also known as combustible ice, and mainly composed of methane, is identified as a potential clean energy for the 21st century. Due to its large reserves, gas hydrate can ease problems caused by energy resource shortage and has gained attention around the world. In this paper, we focus on the exploration and development of gas hydrate as well as discussing its status and future development trend in China and abroad. We then analyze its opportunities and challenges in China from four aspects, resource, technology, economy and policy, with five forces model and Politics Economics Society Technology method. The results show China has abundance gas hydrate resource; however, backward technologies and inadequate investment have seriously hindered the future development of gas hydrate; thus, China should establish relevant cooperation framework and intuitional arrangement to attract more investment as well as breaking through technical difficulties to commercialization gas hydrate as soon as possible.

Seafloor geomorphic manifestations of gas venting and shallow subbottom gas hydrate occurrences

High-resolution multibeam bathymetry data collected with an autonomous underwater vehicle (AUV) complemented by compressed high-intensity radar pulse (Chirp) profiles and remotely operated vehicle (ROV) observations and sediment sampling reveal a distinctive rough topography associated with seafloor gas venting and/or near-subsurface gas hydrate accumulations. The surveys provide 1 m bathymetric grids of deep-water gas venting sites along the best-known gas venting areas along the Pacific margin of North America, which is an unprecedented level of resolution. Patches of conspicuously rough seafloor that are tens of meters to hundreds of meters across and occur on larger seafloor topographic highs characterize seepage areas. Some patches are composed of multiple depressions that range from 1 to 100 m in diameter and are commonly up to 10 m deeper than the adjacent seafloor. Elevated mounds with relief of >10 m and fractured surfaces suggest that seafloor expansion also occurs. Ground truth observations show that these areas contain broken pavements of methane-derived authigenic carbonates with intervening topographic lows. Patterns seen in Chirp profiles, ROV observations, and core data suggest that the rough topography is produced by a combination of diagenetic alteration, focused erosion, and inflation of the seafloor. This characteristic texture allows previously unknown gas venting areas to be identified within these surveys. A conceptual model for the evolution of these features suggests that these morphologies develop slowly over protracted periods of slow seepage and shows the impact of gas venting and gas hydrate development on the seafloor morphology.

RETRACTED: A global survey of gas hydrate development and reserves: Specifically in the marine field

Gas hydrates, also known as methane hydrates, are formed due to the high hydraulic pressures present under the cold seabed over long periods of time. Gas hydrates are mainly composed of methane produced in the seabed by bacteria in the use of the remains of animals and plants as food. Often appearing as translucent or opaque ice, gas hydrates can be separated into water and methane gas, which can be burned at normal temperatures and pressures, giving this substance the nickname “combustible ice.” As global oil reserves continue to be depleted, scientists are regarding methane hydrates as a new energy source that is very likely to replace oil in the 21st century. According to reports by the United States Geological Survey, the potential natural gas energy that can be recovered from global methane hydrate formations is two times the amount of fossil fuel energy available to the world. Therefore, many countries that are deeply engaged in the development of gas hydrates, such as the United States, Japan, Canada, China, India, and Taiwan, hope that this new energy source can become a substitute for more conventional petroleum sources. Japan—the first country to develop methane hydrates—will be ready for commercial mass production in the eastern Japanese Nankai Trough prior to 2018, according to Japan׳s Methane Hydrate R&D Program-MH 21. However, the exploitation of methane hydrates in terrestrial permafrost requires less technical risk and costs. Joint explorations in areas of Alaska by the United States, Japan, and Canada will enter the preparation phase for commercial output as early as 2015. In Taiwan, cooperation with Germany and the United States has led to methane hydrate exploration and the initiation of drilling sampling in the South China Sea that is expected to be completed in 2016, with commercial production ready as soon as 2026.

가스하이드레이트 퇴적층 물성 추정 소프트웨어를 이용한 울릉분지 시추공 자료 해석

미래의 청정 에너지자원인 가스하이드레이트 개발을 위해 국내 부존이 유망한 울릉분지 5개의 지역에 대하여 2007년 시추작업을 수행하여 모든 시추공으로부터 물리검층 자료를 취득하였으며 이중 UBGH1-04, UBGH1-09, UBGH1-10 시추공에서 코어 자료를 취득하였다. 이 연구에서는 기확립한 가스하이드레이트 퇴적층 물성 추정 기법 및 UBGH1-04, UBGH1-09, UBGH1-10 시추공에서의 물성 추정 결과를 바탕으로 사용자 친화적 소프트웨어인 "KMU GH Logs 2010"을 개발하였다. 또한 코어 미회수 시추공인 UBGH1-01 및 UBGH1-14 시추공의 물리검층 자료를 이용하여 가스하이드레이트 퇴적층의 물성을 추정하였다. 밀도 검층 자료를 사용하여 공극률을 추정하였으며, 전기비저항 검층 및 음파 검층을 이용하여 가스하이드레이트포화율을 추정하였다. 물리검층 자료와 코어의 퇴적상 분석 자료를 이용하여 선형 판별 분석 기법을 통해 퇴적상을 추정함으로써 가스하이드레이트 해리의 징후가 나타나는 DITM 및 MSS 퇴적상에 대한 판별이 가능함을 확인하였다. For the development of gas hydrate as new future energy resources, the drilling was carried out at the five locations where have high potential as gas hydrate bearing sediments in Ulleung basin, offshore Korea in 2007. Well log data were obtained from all wells and core data were procured from 3 wells, UBGH1-04, UBGH1-09 and UBGH1-10. In this study, user-friendly software, "KMU GH Logs 2010", is developed and this software is based on the estimation methods developed in previous study for gas hydrate bearing sediments and the properties estimated from UBGH1-04, UBGH1-09 and UBGH1-10. Petrophysical properties in un-cored wells, UBGH1-01 and UBGH1-14, are also estimated by using well log data. Porosity is estimated by density log and gas hydrate saturation is calculated by sonic log and resistivity log. Sedimentary facies are estimated by applying the linear discriminant analysis using both well log and sedimentary facies data from core analysis. It is confirmed that DITM facies and MSS facies appeared signs of gas hydrate disassociation are able to be distinguished by the method.

Review on the gas hydrate development and production as a new energy resource

Gas hydrates consist of guest gas molecules inside hydrogen-bonded water lattices. Natural gas hydrates are found in offshore and permafrost regions. The large amounts of gas hydrate reserves suggest the potential of gas hydrates as an energy resource if economically viable production methods were developed. The proper understandings of hydrate formation/dissociation are important for the drilling and oil production applications. The investigations of physical and geotechnical properties provide the in-depth understandings of the in-situ hydrate formation mechanism and the associated production technologies. The purpose of this review paper is to provide a starting kit for civil engineers who have recently started the research related to the hydrate development and production and want to have insights on the general trends of the hydrate research and the relevant knowledge needed for their research. Gas hydrate explorations include the geophysical explorations, such as the seismic survey, the borehole logging and the geological and geochemical explorations. Gas hydrate productions require the dissociation of gas hydrates, and the production technologies are categorized based on the dissociation techniques involved: depressurization method, thermal stimulation method, and inhibitor injection method. Establishing safe and efficient gas production technology requires the extensive information on the geotechnical characteristics of hydrate reservoirs. Flow assurances, the integrity of sediment formation and the well bore stability are crucial for the safe and efficient productions of gases from gas hydrates in sediments. The strength and deformation characteristics, the fluid migration characteristics, and the thermal conduction characteristics are key factors for controlling the above.

Development of gas hydrates in a deep-water anticline based on attribute analysis from three-dimensional seismic data

Bottom simulating reflectors (BSRs) on two-dimensional (2D) and 3D seismic data commonly mark the contact between a gas hydrate zone and underlying free gas. They are common features across anticlines in the Northwest Borneo Trough. Amplitude analysis of one anticline covered by 3D seismic data has shown that its BSR is associated with a class III type AVO (amplitude variation with offset) anomaly. The positive AVO anomaly and opposite polarity sign to the water bottom is consistent with a gas hydrate over gas interface at the BSR. Bright spots under the BSR with a positive AVO anomaly are interpreted to represent free gas in more permeable units forming a column as much as 250 m deep, trapped by impermeable gas hydrate. Gas is mainly present on the backlimb of the anticline. The depth of the BSR from the water bottom varies spatially and indicates geothermal gradients ranging from 4.8 to 6.4 °C/100 m, unusually high for a deep-water setting. The temperatures are probably indicative of hot fluid transport into the crests of anticlines, as suggested by previous shallow coring surveys. A double BSR is present in some places and interpreted as residual gas hydrate following an upward migration of the base of the gas hydrate stability zone; this feature corresponds with recent deposition of a mass transport flow. BSR events are regionally located within the anticline cores, indicating that they have channeled warm to hot, thermogenically generated hydrocarbon-charged fluids from a large volume of sediment toward the crest of the anticline. Fluid migration is focused along permeable sedimentary units in the backlimb of the folds, up thrust faults at depth, and along vertical fluid pipes and crestal normal faults shallower in the section.

Similarity theory for the physical simulation of natural gas hydrate reservoir development

In order to apply physical simulation results to natural gas hydrate reservoir parameters to provide a theoretical framework for the design of a development plan, an analytical equation method was used to obtain the similarity criteria of natural gas hydrate reservoir development by physical simulation, based on a mathematical model of natural gas hydrate development. Given the approach of numerical simulation, a sensitivity analysis for all parameters was carried out, which specifically demonstrated that initial temperature is the most important parameter. Parameters of thermal conductivity coefficients are not necessary for conducting the NGH dissociation process, which will fundamentally simplify the design and establishment of the model. The analysis provides a sound theoretical basis and design principles for particular similarity.

Alaska North Slope regional gas hydrate production modeling forecasts

A series of gas hydrate development scenarios were created to assess the range of outcomes predicted for the possible development of the “Eileen” gas hydrate accumulation, North Slope, Alaska. Production forecasts for the “reference case” were built using the 2002 Mallik production tests, mechanistic simulation, and geologic studies conducted by the US Geological Survey. Three additional scenarios were considered: A “downside-scenario” which fails to identify viable production, an “upside-scenario” describes results that are better than expected. To capture the full range of possible outcomes and balance the downside case, an “extreme upside scenario” assumes each well is exceptionally productive. Starting with a representative type-well simulation forecasts, field development timing is applied and the sum of individual well forecasts creating the field-wide production forecast. This technique is commonly used to schedule large-scale resource plays where drilling schedules are complex and production forecasts must account for many changing parameters. The complementary forecasts of rig count, capital investment, and cash flow can be used in a pre-appraisal assessment of potential commercial viability. Since no significant gas sales are currently possible on the North Slope of Alaska, typical parameters were used to create downside, reference, and upside case forecasts that predict from 0 to 71 BM 3 (2.5 tcf) of gas may be produced in 20 years and nearly 283 BM 3 (10 tcf) ultimate recovery after 100 years. Outlining a range of possible outcomes enables decision makers to visualize the pace and milestones that will be required to evaluate gas hydrate resource development in the Eileen accumulation. Critical values of peak production rate, time to meaningful production volumes, and investments required to rule out a downside case are provided. Upside cases identify potential if both depressurization and thermal stimulation yield positive results. An “extreme upside” case captures the full potential of unconstrained development with widely spaced wells. The results of this study indicate that recoverable gas hydrate resources may exist in the Eileen accumulation and that it represents a good opportunity for continued research.

Resource potential of gas hydrates: recent contributions from international research and development projects

Abstract It is generally accepted that the amount of gas in the world's gas hydrate accumulations exceeds the volume of known conventional gas resources. Researchers have long speculated that gas hydrates could eventually be a commercial producible energy resource yet technical and economic hurdles have historically made gas hydrate development a distant goal rather than a near-term possibility. This view began to change in recent years with the realization that this unconventional resource could possibly be developed with existing conventional oil and gas production technology. The most significant development has been gas hydrate production testing conducted at the Mallik site in Canada's Mackenzie Delta. The Mallik Gas Hydrate Production Research Well Program has yielded the first modern, fully integrated field study and production test of a natural gas hydrate accumulation. More recently, BP Exploration (Alaska) Inc. with the US Department of Energy and the US Geological Survey have successfully cored, logged and tested a gas hydrate accumulation on the North Slope of Alaska known as the Mount Elbert Prospect. The Mallik project along with the Mount Elbert effort has for the first time allowed the rational assessment of the production response of a gas hydrate accumulation. In addition to the gas hydrate production tests in Canada and the USA, marine gas hydrate research drilling, coring and logging expeditions launched by the national gas hydrate programmes in Japan, India, China and South Korea have also contributed significantly to our understanding of how gas hydrates occur in nature and have provided a much deeper appreciation of the geological controls on the occurrence of gas hydrates. With an increasing number of highly successful gas hydrate field studies, significant progress has been made in addressing some of the key issues on the formation, occurrence and stability of gas hydrates in nature.

Permafrost-associated natural gas hydrate occurrences on the Alaska North Slope

In the 1960s Russian scientists made what was then a bold assertion that gas hydrates should occur in abundance in nature. Since this early start, the scientific foundation has been built for the realization that gas hydrates are a global phenomenon, occurring in permafrost regions of the arctic and in deep water portions of most continental margins worldwide. In 1995, the U.S. Geological Survey made the first systematic assessment of the in-place natural gas hydrate resources of the United States. That study suggested that the amount of gas in the gas hydrate accumulations of northern Alaska probably exceeds the volume of known conventional gas resources on the North Slope. Researchers have long speculated that gas hydrates could eventually become a producible energy resource, yet technical and economic hurdles have historically made gas hydrate development a distant goal. This view began to change in recent years with the realization that this unconventional resource could be developed with existing conventional oil and gas production technology. One of the most significant developments was the completion of the BPXA-DOE-USGS Mount Elbert Gas Hydrate Stratigraphic Test Well on the Alaska North Slope, which along with the Mallik project in Canada, have for the first time allowed the rational assessment of gas hydrate production technology and concepts. Almost 40 years of gas hydrate research in northern Alaska has confirmed the occurrence of at least two large gas hydrate accumulations on the North Slope. We have also seen in Alaska the first ever assessment of how much gas could be technically recovered from gas hydrates. However, significant technical concerns need to be further resolved in order to assess the ultimate impact of gas hydrate energy resource development in northern Alaska.

非在来型石油天然ガス開発技術

While conventional oil and gas production is expected to hit a peak in dozens of years, the world still requires hydrocarbons as the main source of energy. The need to fill the gap between supply and demand, and the recent high oil price, have aroused enthusiasm for unconventional oil and gas. But, the development of them is, full of ups and downs.The extra heavy oil boom began in early 2000's, when large projects started in Canada and Venezuela. But, rising plant cost, shortage of skilled workers, and environmental concerns have increased uncertainty of those projects, and finally this year global economic crunch and oil price plunge ended the boom. In those circumstances, technologies to reduce production cost are keenly craved and several are on trial in actual projects.In 2005, U.S. Congress directed the Bureau of Land Management to manage oil shale development on public lands. By 2008, the bureau issued six research development and demonstration leases that will allow oil shale development to resume on a 160-acre tract of public land. Currently, in-situ conversion process is arguably the most cost effective recovery method.The U.S. has led the world in coalbed methane (CBM) development, and the production reached 1.8 tcf by 2006. While some countries are after the footsteps of the U.S. in CBM development, the U.S. is now considering giving a higher priority to shale gas instead as the results of efforts to develop economical production methods for years.Japan has studied gas hydrate development since 1990's. In 2008, the Japan Oil, Gas and Metals National Corporation carried out a successful gas hydrate production test in Canada. The next step of their pursuit will include practical application of the production method, nationwide potential evaluation, and development of environmental assessment technique.

The path to commercial hydrate gas production

During the course of the past two decades, enormous reserve potential has often been attributed to gas hydrates in marine sediments, yet the commercial development of gas hydrates is widely viewed as a possibility which is 20, 30, or more years away. As a result, the oil and gas industry has been slow to pursue this opportunity, and gas hydrate exploration and production research has been a low priority for most energy companies. This perspective is changing as a result of recent research by universities, government agencies, and international consortia. In particular, a better understanding of gas hydrate formation has developed along with geologic models for the concentration of gas hydrate in potential reservoirs. At the same time, emerging production technology should enable gas hydrate production in the near term, limited more by constraints on infrastructure than by production technology. Given projected higher natural gas prices, gas hydrates will likely emerge as a viable commercial resource in so...