Journal of Natural Gas Science and Engineering最新文献

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Effect of pore water on the depressurization of gas hydrate in clayey silt sediments 孔隙水对泥质淤泥质沉积物中天然气水合物降压的影响
IF 4.965 2区 工程技术
Journal of Natural Gas Science and Engineering Pub Date : 2022-12-01 DOI: 10.1016/j.jngse.2022.104836
Xiaochu Wang , Youhong Sun , Saiyu Peng , Yuanqi Wang , Shengli Li
{"title":"Effect of pore water on the depressurization of gas hydrate in clayey silt sediments","authors":"Xiaochu Wang ,&nbsp;Youhong Sun ,&nbsp;Saiyu Peng ,&nbsp;Yuanqi Wang ,&nbsp;Shengli Li","doi":"10.1016/j.jngse.2022.104836","DOIUrl":"https://doi.org/10.1016/j.jngse.2022.104836","url":null,"abstract":"<div><p>Marine gas hydrate always occurs in clayey silt sediments partially or fully saturated with water. Pore water is involved in gas hydrate formation and decomposition, which plays an important role in gas recovery from hydrate during depressurization. In this work, the depressurization of methane hydrate in the clayey silt sediments was experimentally investigated in a one-dimensional reactor. The variation of gas production and pressure gradient under the gas-rich and water-rich condition were studied. It was found that the gas production in water-rich environment was much lower than that in gas-rich environment as the movement of hydrate dissociating front is slower in water-rich environment. The permeability of the clayey silt sediments was measured before hydrate formation and after hydrate decomposition, which indicated that there was a large depression in the permeability of the clayey silt sediments after hydrate decomposition, which could be attributed to the hydration swelling of clay minerals with the expansion of diffuse double layer caused by the release of water with lower salinity from gas hydrate dissociation. And the permeability depression of the clayey silt sediments caused by hydrate decomposition was more obvious in water-rich environment, reaching up to ∼50%, and increased with the content of clay minerals. In addition, inorganic salt-based clay stabilizer solution was pre-injected into the clayey silt gas hydrate-bearing sediments before depressurization to mitigate the formation damage during gas hydrate production. The results showed the permeability of the sediments pre-saturated with NH<sub>4</sub>Cl was maintained at ∼75% of the initial values after gas hydrate decomposition as the exchange of Na<sup>+</sup> with NH<sub>4</sub><sup>+</sup> in sediments was proved to decrease the bound water in montmorillonite interlayers by NMR analysis and inhibit the hydration swelling of clay particles.</p></div>","PeriodicalId":372,"journal":{"name":"Journal of Natural Gas Science and Engineering","volume":"108 ","pages":"Article 104836"},"PeriodicalIF":4.965,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"1813550","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 2
Effects of fluid and proppant properties on proppant transport and distribution in horizontal hydraulic fractures of coal under true-triaxial stresses 真三轴应力作用下流体和支撑剂性质对水平水力裂缝中支撑剂运移和分布的影响
IF 4.965 2区 工程技术
Journal of Natural Gas Science and Engineering Pub Date : 2022-12-01 DOI: 10.1016/j.jngse.2022.104795
Haoze Li, Bingxiang Huang, Xinglong Zhao, Zhanwei Wu, Xuejie Jiao, Xiaoke Han, Zheng Sun
{"title":"Effects of fluid and proppant properties on proppant transport and distribution in horizontal hydraulic fractures of coal under true-triaxial stresses","authors":"Haoze Li,&nbsp;Bingxiang Huang,&nbsp;Xinglong Zhao,&nbsp;Zhanwei Wu,&nbsp;Xuejie Jiao,&nbsp;Xiaoke Han,&nbsp;Zheng Sun","doi":"10.1016/j.jngse.2022.104795","DOIUrl":"https://doi.org/10.1016/j.jngse.2022.104795","url":null,"abstract":"<div><p><span><span><span>Proppant<span> distribution and sedimentary area spacing are crucial factors that influence fracture closure<span>, and they directly impact the efficiency and effective utilisation time of unconventional oil and gas. However, the fracture surface<span> roughness of actual hydraulic fractures and the development of microfractures significantly impact </span></span></span></span>proppant transport<span><span>. Few proppant transport laws for hydraulic fractures under true-triaxial stresses have been proposed. In this study, the effects of fluid and proppant properties on proppant transport and distribution in horizontal coal hydraulic fractures were investigated using a true-triaxial hydraulic fracturing experimental system subjected to high-pressure sand injection. The results show that high-injection-rate fracturing and low-injection-rate sand injection facilitate proppant transport to </span>fracture tip and increase the distribution area of the proppant in fractures. The high viscosity of sand-carrying fluid improves the carrying capacity of the proppant but also increases the transport resistance. The resistance and the buoyancy of the high-viscosity fluid make the proppant transport complex. The higher the </span></span>proppant concentration, the larger the proppant settlement at the crack entrance, and the closer the proppant-transport distance. During multiple sand injections, the proppant injected previously is pressed into the </span>coal seam<span> under the closure stress. The stress required to migrate the proppant injected subsequently is higher, and the proppant settlement at the crack inlet is larger. The smaller the proppant particle<span> size, the easier the proppant penetrates the microcracks<span>; this is more conducive to reaching the crack tip and promoting the fracture network development.</span></span></span></p></div>","PeriodicalId":372,"journal":{"name":"Journal of Natural Gas Science and Engineering","volume":"108 ","pages":"Article 104795"},"PeriodicalIF":4.965,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"1826671","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 9
The effect of different CO2 phases on wormhole development in carbonate rocks 不同CO2相对碳酸盐岩虫孔发育的影响
IF 4.965 2区 工程技术
Journal of Natural Gas Science and Engineering Pub Date : 2022-12-01 DOI: 10.1016/j.jngse.2022.104779
Hamad Alarji , Stuart Clark , Klaus Regenauer Lieb
{"title":"The effect of different CO2 phases on wormhole development in carbonate rocks","authors":"Hamad Alarji ,&nbsp;Stuart Clark ,&nbsp;Klaus Regenauer Lieb","doi":"10.1016/j.jngse.2022.104779","DOIUrl":"https://doi.org/10.1016/j.jngse.2022.104779","url":null,"abstract":"<div><p><span>Acid stimulation is commonly used for carbonate reservoirs<span> to enhance wells’ productivity by creating highly conductive channels called wormholes. The success of the stimulation depends on how deep these channels penetrate the formation. Hydrochloric acid (HCl) is commonly used for the carbonate stimulation process with carbon dioxide (CO</span></span><sub>2</sub><span>) as a byproduct of the reaction between HCl and calcium carbonate (CaCO</span><sub>3</sub>). Depending on the operating temperature and pressure, CO<sub>2</sub><span> can form a gaseous phase (bubbles) or be dissolved completely in the fluid. To achieve an understanding of the effect of CO</span><sub>2</sub><span> bubble formation on wormhole development, we used a low acid concentration (not more than 1 wt% HCl) at a range of flow rates. In this study, an elevated back pressure of 8.2 MPa is applied to keep the CO</span><sub>2</sub><span> dissolved in the solution and then compared with another set of experiments where no back pressure is applied. Sensitivity runs on various back pressures (while keeping all other parameters constant) are conducted to acquire a detailed understanding of the wormhole behaviour at a range of back pressures (0.1, 2.7, 5.5 and 8.2 MPa). We test the results in the dissolution phase space of Peclet and Damköhler dimensionless numbers<span>. Although we show that for constant flow rate conditions, the existence of gaseous CO</span></span><sub>2</sub> significantly increases the pressure prior to the wormhole breakthrough, surprisingly no noticeable effect on the wormhole initiation process itself was found.</p></div>","PeriodicalId":372,"journal":{"name":"Journal of Natural Gas Science and Engineering","volume":"108 ","pages":"Article 104779"},"PeriodicalIF":4.965,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"1813547","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 2
Effects of CO2 intrusion on pore structure characteristics of mineral-bearing coal: Implication for CO2 injection pressure CO2侵入对含矿煤孔隙结构特征的影响:对CO2注入压力的启示
IF 4.965 2区 工程技术
Journal of Natural Gas Science and Engineering Pub Date : 2022-12-01 DOI: 10.1016/j.jngse.2022.104808
Xiaolei Wang , Dongming Zhang , Jiabo Geng , Zhehui Jin , Chongyang Wang , Kangde Ren
{"title":"Effects of CO2 intrusion on pore structure characteristics of mineral-bearing coal: Implication for CO2 injection pressure","authors":"Xiaolei Wang ,&nbsp;Dongming Zhang ,&nbsp;Jiabo Geng ,&nbsp;Zhehui Jin ,&nbsp;Chongyang Wang ,&nbsp;Kangde Ren","doi":"10.1016/j.jngse.2022.104808","DOIUrl":"https://doi.org/10.1016/j.jngse.2022.104808","url":null,"abstract":"<div><p>CO<sub>2</sub><span> intrusion has a crucial effect on the pore structure of mineral-bearing coal. In this study, we selected long flame coal, lean coal, and anthracite after CO</span><sub>2</sub><span> adsorption at different pressures and tested the coal samples using X-ray diffraction, mercury intrusion porosimetry, and N</span><sub>2</sub><span> (77 K) adsorption methods. The tests were conducted to determine the variations in mineral content, pore structure, and fractal characteristics. The results showed that supercritical CO</span><sub>2</sub> had a greater ability to dissolve minerals in coal than that of subcritical CO<sub>2</sub>. Although the total pore volume and BET specific surface area gradually increased with the increase in CO<sub>2</sub><span> intrusion pressure in coal, the transformation of different pores and partial new pores caused by the dissolution of minerals and the adsorption swelling of coal matrix caused the micro-macropores in the three coal samples to exhibit different trends. The pore surface roughness and pore structure complexity of seepage pore in the long-flame coal after CO</span><sub>2</sub> adsorption increased while those of the lean coal and anthracite decreased. Meanwhile, CO<sub>2</sub> intrusion caused the surface of the adsorption pore in coal to become smooth, and the pore structure was more regular, except for the lean coal. A conceptual model of the mineral-bearing coal was developed to describe the relationship between the mineral composition and pore structure induced by CO<sub>2</sub> intrusion. These findings help to understand the transformation effect of CO<sub>2</sub><span> on coal seams. Thus, a higher CO</span><sub>2</sub><span> injection pressure<span> should be used to obtain a larger injection volume and shorter injection time during CO</span></span><sub>2</sub> storage implementation.</p></div>","PeriodicalId":372,"journal":{"name":"Journal of Natural Gas Science and Engineering","volume":"108 ","pages":"Article 104808"},"PeriodicalIF":4.965,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"1826672","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 5
Alternative flow model of anisotropic porous media 各向异性多孔介质的可选流动模型
IF 4.965 2区 工程技术
Journal of Natural Gas Science and Engineering Pub Date : 2022-12-01 DOI: 10.1016/j.jngse.2022.104829
Chang-Hoon Shin
{"title":"Alternative flow model of anisotropic porous media","authors":"Chang-Hoon Shin","doi":"10.1016/j.jngse.2022.104829","DOIUrl":"https://doi.org/10.1016/j.jngse.2022.104829","url":null,"abstract":"<div><p>Porous flow is typically analyzed by the Kozeny–Carman equation using geometric variables, such as hydraulic diameter and tortuosity. The hydraulic tortuosity was first described by Kozeny, and later redefined by Carman as the tortuosity square term in the Kozeny–Carman equation. However, the revised term correlating the flow velocity with path length square would be physically ambiguous. Moreover, the hydraulic diameter, which is directly correlated to the permeability and interstitial velocity in the Kozeny–Carman equation, is an isotropic constant property; thus, it should be verified whether the isotropic hydraulic diameter can reasonably correlate each anisotropic directional flow feature passing through heterogeneous complex media. Accordingly, the Kozeny–Carman equation was theoretically examined and experimentally verified in this study to obtain the proper correlation based on the definitions of truly equivalent diameter and tortuosity. Therefore, the effective variables of porous media were presented, and it confirmed that the effective diameter corresponded to the physically equivalent diameter of anisotropic porous media. Moreover, using the mass conservation relation, it was verified that Kozeny's tortuosity is exactly associated with the truly equivalent flow model, and then the Kozeny constant must be differently defined from the original Kozeny equation. Accordingly, the Kozeny–Carman equation was improved by appertaining either effective diameter or tortuosity, and the momentum conservation relation was used to verify it. The pore-scale simulations using 5-sorts of 25-series porous media models were performed to test the validity of derived effective variables and revised equations. Finally, the alternative flow model of anisotropic porous media was presented using equivalent geometric and frictional flow variables. Subsequently, their practical and more accurate estimations were achieved by introducing the concentric annulus flow model under the special hydraulic condition. The new variables and relations are expected to be usefully applied to various porous flow analyses, such as interstitial velocity estimations, geometric condition variations, flow regime changes, and anisotropic heat and multiphase flows.</p></div>","PeriodicalId":372,"journal":{"name":"Journal of Natural Gas Science and Engineering","volume":"108 ","pages":"Article 104829"},"PeriodicalIF":4.965,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"1830305","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 2
On gas transport modes in matrix-fracture systems with arbitrary multiscale configurations 任意多尺度结构的基质-裂缝系统中的气体输运模式
IF 4.965 2区 工程技术
Journal of Natural Gas Science and Engineering Pub Date : 2022-12-01 DOI: 10.1016/j.jngse.2022.104839
Hong Zuo , Farzam Javadpour , Cheng Zhai , Shouchun Deng , Haibo Li
{"title":"On gas transport modes in matrix-fracture systems with arbitrary multiscale configurations","authors":"Hong Zuo ,&nbsp;Farzam Javadpour ,&nbsp;Cheng Zhai ,&nbsp;Shouchun Deng ,&nbsp;Haibo Li","doi":"10.1016/j.jngse.2022.104839","DOIUrl":"https://doi.org/10.1016/j.jngse.2022.104839","url":null,"abstract":"<div><p><span><span><span>Tight shale reservoirs exhibit high heterogeneity and strong anisotropy in multiscale pore/fracture networks, with highly variable properties. The local equilibrium or non-equilibrium states vary spatially and are strongly controlled by the gas transport modes at each scale. A fundamental understanding of the coupling effects of gas flow in heterogeneous </span>porous media with arbitrary </span>scale ratios<span><span> is crucial but not yet available. Here, we systematically and theoretically study the gas transport modes and gas flow velocity in multiscale matrix-fracture systems using the asymptotic homogenization method. A series of exact scaling laws for the </span>gas velocity<span> in heterogeneous porous media with arbitrary multiscale configurations are established, and the local equilibrium/non-equilibrium effects at each scale are analyzed in detail. It is shown that the gas transport modes between two adjacent porous media can be classified into four distinct types governed by two characteristic time scales (rather than two types as commonly reported). We demonstrate an ultrahigh pressure gradient in a thin depressurized zone in the matrix that can reach </span></span></span><span><math><mrow><msup><mn>10</mn><mn>3</mn></msup><mspace></mspace><mo>∼</mo><mspace></mspace><msup><mn>10</mn><mn>5</mn></msup></mrow></math></span><span> times the macroscopic pressure gradient, greatly increasing gas flow rates<span> by three to five orders of magnitude. The hydraulically-created fractures not only provide preferential flow pathways, but more importantly, they increase the gas velocity in the matrix (which does not contain any fractures) by several orders of magnitude. The work also sheds light on the discrepancy between the observed high gas production and the experimentally measured low permeability in drilled cores.</span></span></p></div>","PeriodicalId":372,"journal":{"name":"Journal of Natural Gas Science and Engineering","volume":"108 ","pages":"Article 104839"},"PeriodicalIF":4.965,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"3137332","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 1
Experimental characterization of the difference in induction period between CH4 and CO2 hydrates: Motivations and possible consequences on the replacement process CH4和CO2水合物诱导期差异的实验表征:对替代过程的动机和可能后果
IF 4.965 2区 工程技术
Journal of Natural Gas Science and Engineering Pub Date : 2022-12-01 DOI: 10.1016/j.jngse.2022.104848
Alberto Maria Gambelli, Federico Rossi
{"title":"Experimental characterization of the difference in induction period between CH4 and CO2 hydrates: Motivations and possible consequences on the replacement process","authors":"Alberto Maria Gambelli,&nbsp;Federico Rossi","doi":"10.1016/j.jngse.2022.104848","DOIUrl":"https://doi.org/10.1016/j.jngse.2022.104848","url":null,"abstract":"<div><p><span>The present research explores the differences in induction time between methane and carbon dioxide hydrates. This parameter was calculated by considering the heat released during the formation of hydrates. Being the process exothermic, the heat released, in conjunction with the enthalpy of formation, allowed to calculate the quantity of hydrates formed as soon as the process became detectable. This information was then combined with the measure of time to define the induction period. The procedure was selected in order to avoid possible errors related to the dissolution of carbon dioxide in water, which may affect the accuracy of detection. It was found that the induction time is significantly longer for carbon dioxide hydrates. It can be explained with the non-hydrophobicity of the molecule and with the higher Gibbs free energy barrier which must be overcome to produce the first nuclei of CO</span><sub>2</sub><span> hydrates. The reliability of the proposed method was verified by evaluating the gas absorption over time for methane, whose dissolution in water can be considered negligible. Finally, it was proved that, after the formation of the first conglomerates, the growth of carbon dioxide hydrates is faster than that of methane hydrates, due to the higher degree of mixing between water and gas molecules within the whole formation environment.</span></p></div>","PeriodicalId":372,"journal":{"name":"Journal of Natural Gas Science and Engineering","volume":"108 ","pages":"Article 104848"},"PeriodicalIF":4.965,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"1813548","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 4
The role of storage systems in hydrogen economy: A review 储氢系统在氢经济中的作用综述
IF 4.965 2区 工程技术
Journal of Natural Gas Science and Engineering Pub Date : 2022-12-01 DOI: 10.1016/j.jngse.2022.104843
T. Amirthan, M.S.A. Perera
{"title":"The role of storage systems in hydrogen economy: A review","authors":"T. Amirthan,&nbsp;M.S.A. Perera","doi":"10.1016/j.jngse.2022.104843","DOIUrl":"https://doi.org/10.1016/j.jngse.2022.104843","url":null,"abstract":"<div><p><span><span>An economy based on hydrogen is widely regarded as the potential successor of the fossil-fuel-driven present energy sector. One major obstacle in developing the hydrogen economy<span><span> is the suitable storage systems for different applications. This article presents an overview of the role of different storage technologies in successfully developing the hydrogen economy. It reviews the present state of various </span>hydrogen storage systems from the surface and </span></span>underground storage<span><span> methods, their applications, and the associated scientific challenges. The integration of renewable energy in existing energy infrastructure requires developing suitable storage solutions along the energy supply chain. Large-scale seasonal hydrogen storage can be achieved through a subsurface geologic medium such as salt caverns, depleted </span>hydrocarbon reservoirs<span>, aquifers and hard rock caverns<span>. The suitability of the geostructures depends on the desired storage cycles, capacities, and purity of stored hydrogen. The storage of hydrogen for stationary and mobile applications according to end user demands, generally less in capacity and requiring rapid storage cycles, is facilitated by surface storage methods. The physical storage of hydrogen is trapping it in vessels in its different physical states, such as compressed gaseous, cryogenic and cryo-compressed forms. Material-based storage of hydrogen is by adsorbing or absorbing hydrogen using solid-state materials. The performance of surface storage technics is characterized by gravimetric and volumetric densities, storage uptake and release kinetics, the cost involved, and operational safety. The technical insights of each storage technology are presented with recommendations and relevant fields of applications. No storage technic in its ideal conditions can be considered the best fit for all the applications, and each technic requires intense work to become acceptable for </span></span></span></span>energy application.</p></div>","PeriodicalId":372,"journal":{"name":"Journal of Natural Gas Science and Engineering","volume":"108 ","pages":"Article 104843"},"PeriodicalIF":4.965,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"1826670","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 19
Effects of hydrate occurring mechanisms and saturation on the mechanical properties of hydrate-bearing sediments: Numerical study based on simplified DEM simulation 水合物发生机制和饱和度对含水沉积物力学性质的影响——基于简化DEM模拟的数值研究
IF 4.965 2区 工程技术
Journal of Natural Gas Science and Engineering Pub Date : 2022-12-01 DOI: 10.1016/j.jngse.2022.104804
Zhenhua Han , Luqing Zhang , Jian Zhou , Zhejun Pan , Song Wang , Ruirui Li
{"title":"Effects of hydrate occurring mechanisms and saturation on the mechanical properties of hydrate-bearing sediments: Numerical study based on simplified DEM simulation","authors":"Zhenhua Han ,&nbsp;Luqing Zhang ,&nbsp;Jian Zhou ,&nbsp;Zhejun Pan ,&nbsp;Song Wang ,&nbsp;Ruirui Li","doi":"10.1016/j.jngse.2022.104804","DOIUrl":"https://doi.org/10.1016/j.jngse.2022.104804","url":null,"abstract":"<div><p><span>Natural gas hydrate is a strategic </span>alternative energy source<span> which are widely founded in seabed sediments. The study of the mechanical properties of hydrate-bearing sediments is the key content to ensure the safe exploitation of gas hydrate. Hydrate occurring mechanisms and saturation are important factors affecting the mechanical properties of hydrate-bearing sediments. In this work, simplified discrete element models that consider the hydrate occurring mechanism, hydrate saturation and confining pressure, were generated based on PFC code. Three main hydrate occurring mechanisms including pore filling, load bearing and cementation<span> were characterized. The triaxial compression simulation was then conducted to investigate the model mechanical properties. The results show that the hydrate of cementation mode has the most obvious strength-enhancing effect on sediments, followed by the load bearing model and pore filling model. Hydrate occurring mechanism also affect the increasing trend of sediment strength and deformation modulus with hydrate saturation and confining pressure. The influence of hydrate occurrence mechanism on the mechanical behavior of sediment is largely controlled by the interaction between hydrate and sand particles interface. The hydrate of cementation mode increases the cohesion of the sediment particles, the hydrate of pore filling mode increases the friction between particles, and the hydrate of load bearing mode has the combined effects of the above two.</span></span></p></div>","PeriodicalId":372,"journal":{"name":"Journal of Natural Gas Science and Engineering","volume":"108 ","pages":"Article 104804"},"PeriodicalIF":4.965,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"1826673","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 4
Prediction of liquid surge volumes and flow rates for gas wells using machine learning 利用机器学习预测气井的液体涌动体积和流速
IF 4.965 2区 工程技术
Journal of Natural Gas Science and Engineering Pub Date : 2022-12-01 DOI: 10.1016/j.jngse.2022.104802
Youngwoo Yun , Teawoo Kim , Saebom Hwang , Hyunmin Oh , Yeongju Kim , Hoonyoung Jeong , Sungil Kim
{"title":"Prediction of liquid surge volumes and flow rates for gas wells using machine learning","authors":"Youngwoo Yun ,&nbsp;Teawoo Kim ,&nbsp;Saebom Hwang ,&nbsp;Hyunmin Oh ,&nbsp;Yeongju Kim ,&nbsp;Hoonyoung Jeong ,&nbsp;Sungil Kim","doi":"10.1016/j.jngse.2022.104802","DOIUrl":"https://doi.org/10.1016/j.jngse.2022.104802","url":null,"abstract":"<div><p>Liquid surge refers to an excessive liquid inflow to a slug catcher or a separator and is one of the main issues in flow assurance. The wellhead choke valves of gas wells must be adjusted to maintain the target flow rate as the reservoir pressure drops. The wellhead choke opening can be determined by conducting multiphase pipeline transient flow simulations to achieve the target flow rate and avoid liquid surges. However, it is not financially and computationally practical to conduct many multiphase transient pipeline flow simulations simultaneously for hundreds of wells. We found that flow rates and maximum liquid surge volumes for gas wells can be predicted accurately using simple machine learning models when the wellhead choke valve is adjusted. The machine learning models provided accurate predictions (R<sup>2</sup> &gt; 0.99) regarding flow rates and maximum liquid surge volumes for different wellhead pressure drop plans, vertical and horizontal well lengths, and current operating conditions in cases involving two real fields, the Horn River Basin (HRB) and Rakhine Basin field. The wellhead operating conditions that are appropriate for achieving the target flow rate and avoiding liquid surges can be efficiently determined using the machine learning models instead of multiphase transient pipeline flow simulators. The proposed approach also accurately estimated downhole pressures that are necessary to evaluate reservoir performances given wellhead pressures and flow rates. Lastly, we presented what features are dominant in predicting liquid surge volumes, flow rates, and downhole pressures in feature importance analyses.</p></div>","PeriodicalId":372,"journal":{"name":"Journal of Natural Gas Science and Engineering","volume":"108 ","pages":"Article 104802"},"PeriodicalIF":4.965,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"1826675","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 2
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