Papers by Keyword: Natural Gas Hydrate

Abstract: 3D visualization technology is a tool used for displaying, describing, and understanding the characteristics of geologic bodies, and features high efficiency, objective accuracy, visual expression, etc. In this paper, the man-machine interactive interpretation and 3D visualization technology rapidly displaying and analyzing the 3D seismic data of hydrate ore volume is researched and developed using the hybrid rendering technique. Through the integrated interpretation on the 3D space structure, stratum, and seismic attributes, the visualized multi-attribute superimposition analysis is implemented for describing the spatial distribution characteristics of hydrate ore volume and exquisitely describing the subtle geological characteristics of hydrate ore volume. By the hybrid rendering technique, authentication and interpretation are provided for the geological exploration work, so as to greatly enhance the visualization and accuracy of the geological analysis, and also provide a good decision-making foundation for the subsequent development of resources.

Abstract: Natural Gas Hydrate has become a research focus at home and abroad at present. This paper expounds the concept of natural gas hydrate and its types. Analyze its study process and research situation, and make a brief description of its distribution, mining and related environmental problems by tracking the discovery history of gas hydrates. Then put forward the problems in instant need of solving and the key research contents.

Abstract: With the further development of national economy, people have become more concerned about the environment quality. Especially in recent years, due to the frequent occurrence of hazy weather, there has been a growing demand for clean energy [Fig. 1]. As one kind of non-conventional energy, natural gas hydrate, featured by large reserves and relatively clean products of combustion, is considered by the scientific community to be an alternative energy resource in replacement of coal and petroleum. This paper gives a brief introduction of the research progress of natural gas hydrate both at home and abroad, presents the research results and the obstacles in the next step to be taken for China, and then looks into the future development trend.

Abstract: Based on multiphase flow theory and calculation method, the distribution of internal multiphase flow field in the vertical rise pipeline of natural gas hydrate is simulated with FLUENT as a tool and the mixture of natural gas hydrate solid particles and water as a medium. The change rules of velocity field and volume concentration field are described and the effect of solid particles diameter, density and volume concentration of the natural gas hydrate on the pressure loss and resistance loss of pipeline is also analyzed deeply. It provides theoretical basis on transporting of natural gas hydrate solid particles by pipeline. Keywords:natural gas hydrate. pipeline. solid-liquid two-phase flow. kinetic characteristic. numerical simulation.

Abstract: Several geological factors can have a potential effect on dissociation of natural gas hydrate (NGH). It is important to understand their roles in safe exploitation of NGH deposits. This paper accordingly reviews experimental and numerical-modeling researches on impact factors of NGHs dissociation by depressurization. NGHs dissociation usually increases with increasing temperature, permeability, water saturation, thermal conductivity of sediments and depressurization rate of production well, whereas it is reverse for pressure, hydrate saturation, production wells pressure, gas saturation and particle size. Comparably, the effect of porosity and the heat conduction of production well can be reasonably ignored at different spatial scales. The heterogeneity of NGH deposits, chemical components of pore fluids, relative permeability and capillary pressure can also play a role in NGHs dissociation. However, their influencing mechanisms still need further studies in future.

Abstract: Well logging interpretation is a simple and effective method to identify natural gas hydrate,because the cost of the drilling core is high and BSR technology can not be used in the permafrost zone.Establish methods of logging interpretation of gas hydrates on the basis of comprehensive analysis of geological and geographical conditions, combined with the geophysical response characteristics of the gas hydrate. Confirm the distribution of natural gas hydrate and the characteristics of distribution in Muli Coalfield under the guidance of the method. All these can provide fundamental data and scientific proof to the evaluation and target selection of the study area , and also to the discovery of natural gas hydrate in wider area of our country .

Abstract: An experiment on effects of composite promoting agents composed of surfactants and liquid hydrocarbons on hydrate formation was conducted and hydrate formation temperature, pressure, induction time and rate with different composite promoting agent portfolios were measured. Surfactants used were sodium dodecyl sulfate (SDS), sodium dodecyl benzene sulfonate(SDBS) and 2-octyl sodium dodecyl sulfate(GC20S), and liquid hydrocarbon additives utilized were ring silane e (CP) and methyl cyclohexane (MCH). It appeared that all these combinations of composite promoting agents could promote hydrate formation. Type II and H hydrate formation conditions with composite promoting agents CP+GC20S and MCH+GC20S respectively were the mildest and the induction time was the shortest.

Abstract: The paper developed the new compound accelerator contains liquid hydrocarbons and surfactants, using the hydrate generator to experiment. On the basis of the researches on the generating conditions, mechanism of gas hydrate and experimental phenomena, the new kinetics model considering the compound accelerator affecting is built. A program which can compute the model is designed by Visual B compiler language. The induction time in the conditions of different pressures, different solutions and different gases is respectively calculated. The calculation is good agreement with the experimental data and the theory, we obtained that the calculated data are validated. The results show that the model can express completely the process of NGH formation, and provide the theory and model for its industry application.

Abstract: Natural gas hydrate in ocean bottom and permafrost is a great potential energy resource. Compared to fluids hydrocarbons (oil, water and gas) in conventional reservoir evaluation, natural gas hydrate exists in sedimentary formations in solid form, which should be reconsidered in its reservoir evaluation and global reserves assessment. Nuclear magnetic resonance (NMR) technique plays an important role in natural gas hydrate reservoir evaluation. The recent applications of NMR logging in natural gas hydrate reservoir evaluation including formation porosity-permeability estimation, gas hydrate saturation estimation and growth habits prediction in rock pores are introduced. Finally, the potential combination application of downhole NMR 1H relaxation and 13C spectroscopy in natural gas hydrate reservoir evaluation model is also discussed.

Abstract: Research on Natural Gas Hydrate（NGH）is very popular in recent years. NGH is a potential, new and clean energy with the characteristics of high energy density, high combustion heat, high proven reserves, no pollution, wide distribution and shallow burial and so on. It has been identified that NGH is widely distributed in the plateau, arctic permafrost and some eligible areas in the seabed of epicontinental and continental slope all around the world. According to the research data on NGH at home and abroad, the mineralizing, formation, distribution and exploration technology of NGH are introduced as well as the NGH research status of countries in the world, including China. Many theories and techniques about the exploitation of NGH are not mature yet. Numerous problems still exist in industrial mining NGH, such as environmental, geological problems induced by mining NGH and storage and transportation problems after mining. Finally, the application and mining prospects of NGH are and prospected and summarized to provide a relatively comprehensive reference to this research field.