推薦論文摘要

祁連山凍土區(qū)DK-9孔溫度監(jiān)測及天然氣水合物穩(wěn)定帶厚度

王超群，丁瑩瑩，胡道功，等

推薦論文摘要

祁連山凍土區(qū)DK-9孔溫度監(jiān)測及天然氣水合物穩(wěn)定帶厚度

王超群，丁瑩瑩，胡道功，等

祁連山凍土區(qū)木里盆地三露天井田自2008年首次鉆采到天然氣水合物實物樣品以來，實現了中低緯度高山凍土區(qū)天然氣水合物勘探的重大突破。天然氣水合物鉆孔 DK-9于2013年發(fā)現水合物，通過對該孔長期地溫實時監(jiān)測，獲得了穩(wěn)態(tài)的地溫數據。結果表明，祁連山多年凍土區(qū)聚乎更礦區(qū)三露天井田凍土層底界為約163 m，凍土層的厚度達約160 m，凍土層內的地溫梯度為1.38℃/100 m，凍土層以下的地溫梯度達4.85℃/100 m。根據天然氣水合物形成的溫-壓條件分析，聚乎更礦區(qū)具備較好的天然氣水合物形成條件，天然氣水合物穩(wěn)定帶底界深度處于510～617 m之間。

天然氣水合物；溫度監(jiān)測；地溫梯度；水合物穩(wěn)定帶；祁連山

來源出版物：現代地質, 2017, 31(1): 158-166

聯系郵箱：胡道功，hudg@263.net

多孔介質中天然氣水合物生成的主要影響因素

Khlebnikov VN，Antonov SV，Mishin AS，等

摘要：目前有關天然氣水合物（以下簡稱水合物）的研究主要集中在物理化學性質考察和開采（分解）方法探索方面。在進行后者的研究過程中，地層滲流過程的物理模擬至關重要，但目前借助于石油開采研究中廣泛應用的填砂管等多孔介質對水合物進行動態(tài)過程的研究卻鮮有報道。為此，利用河砂填砂管在巖心驅替裝置上進行了甲烷水合物生成過程的物理模擬，考察了地層溫度、甲烷壓力及地層模型性質參數等對水合物生成過程的影響。結果表明：（1）利用冰融水作為地層模型的束縛水可顯著提升甲烷水合物的生成速率；（2）多孔介質條件下過程驅動力（即實驗壓力或溫度偏離水合物相平衡對應值的程度）對甲烷水合物的生成起著決定性作用；（3）當甲烷壓力高于水合物相平衡壓力1.4倍以上，或者實驗溫度低于相平衡溫度3℃以下時，甲烷水合物生成誘導期幾乎不隨溫壓條件的變化而變化；（4）滲透率、含水飽和度、潤濕性等參數對實驗中甲烷水合物的生成率不構成明顯影響。

關鍵詞：甲烷水合物；多孔介質；生成過程；天然氣水合物地層；物理模擬；影響因素；誘導期；生成率

來源出版物：天然氣工業(yè), 37(5): 38-45

聯系郵箱：Khlebnikov VN，khlebnikov_2011@mail.ru

基于支持向量機結合遺傳算法的天然氣水合物相平衡研究

馬貴陽，宮清君，潘振，等

摘要：天然氣水合物（以下簡稱水合物）具有高儲氣率和高可靠性等優(yōu)點，在天然氣儲存及運輸方面具有廣泛的應用前景，同時水合物的存在也會給輸氣管道帶來堵塞等嚴重影響，因此對水合物的生成研究具有重要意義。為此，對Ⅰ型水合物在無添加劑條件下的靜態(tài)生成規(guī)律進行了研究。首先基于水合物動力學實驗裝置進行一系列實驗，然后利用支持向量機（SVM）結合遺傳算法（GA）建立了水合物生成預測模型（SVM＋GA）。據此將實驗中得到的溫度和壓力數據進行預測和優(yōu)化處理，并對上述數據進行非線性擬合，得出了相平衡曲線及其方程，計算得出了常溫下生成水合物的相平衡壓力為33.5 MPa，常壓下生成水合物的相平衡溫度為237.1 K。將分別由SVM+GA模型、Chen-Guo模型和vd W-P熱力學模型所得到的數據與經典的實驗數據進行了對比，其平均相對誤差分別為2.678%、1.447%和3.249%。結論認為：SVM+GA模型具有較高的計算準確度，比Chen-Guo模型和vd W-P熱力學模型更為簡便，可為水合物開發(fā)研究提供更多的數據。

關鍵詞：天然氣水合物；可靠性；支持向量機；遺傳算法；相平衡曲線；平均相對誤差；計算準確度

來源出版物：天然氣工業(yè), 2017, 37(5): 46-52

聯系郵箱：馬貴陽，guiyangma1@163.com

天然氣水合物形成與生長影響因素綜述

丁麟，史博會，呂曉方，等

摘要：天然氣水合物（NGH）是水分子和天然氣分子形成的一種復雜的籠型晶體，其在油氣管道輸送、天然氣儲存和制冷等行業(yè)中都具有重要的研究意義和利用價值，但天然氣水合物的形成是一個多組分、多階段的復雜過程，不同因素對于天然氣水合物形成和生長的影響尚有待明確。本文介紹了天然氣水合物形成的物理過程以及水合物成核的3種機理假說；詳細梳理了基質兩親性、添加劑、多孔介質環(huán)境和雜質、液體組成、溫度壓力以及流動條件等因素對于天然氣水合物形成和生長的影響，并對其作了簡要分析。同時指出，原油組成對于水合物抑制效果的定量化、蠟晶結構對于水合物形成過程中傳質和傳熱的影響以及微觀化的動力學抑制劑抑制機理等都是水合物相關研究中需要進一步深入探究和明確的問題。

關鍵詞：天然氣水合物；物理過程；形成；生長；影響因素

來源出版物：化工進展, 2016, 35(01): 57-64

聯系郵箱：宮敬，ydgj@cup.edu.cn

南海天然氣水合物遠景區(qū)海洋可控源電磁探測試驗

景建恩，伍忠良，鄧明，等

摘要：為了測試我國自主設計與研發(fā)的海洋可控源電磁儀器性能及其在水合物探測中的適用性，本文從海洋可控源電磁法基本原理出發(fā)，首先根據試驗海域水合物地質特征，建立簡化地電模型開展理論研究，確定海洋可控源電磁試驗的技術方案；利用研發(fā)的海洋可控源電磁儀器，在南海天然氣水合物遠景區(qū)開展探測試驗，首次獲得了我國深水海域的海洋可控源電磁數據。通過對采集數據進行處理與反演，獲得了試驗剖面的海底電性結構模型，揭示了4號測點下方存在一個50 m厚的高阻層，其電阻率為25 Ωm、頂部埋深為181 m，為該區(qū)天然氣水合物調查提供了有價值的電性參考資料。研究結果表明，自主研發(fā)的海洋可控源電磁儀器性能達到了預期的設計指標，這標志著我國海洋可控源電磁探測技術向實用化進程邁出了重要一步。

關鍵詞：海洋可控源電磁法；天然氣水合物；南海；數據處理；反演

來源出版物：地球物理學報, 2016, 59(7): 2564-2572

聯系郵箱：伍忠良，52936891@qq.com

南海東北部陸坡天然氣水合物鉆探區(qū)生物地層與沉積速率

陳芳，莊暢，周洋，等

摘要：2013年我國首次在南海東北部東沙陸坡實施天然氣水合物鉆探，并獲取塊狀等可視天然氣水合物樣品。為了解鉆區(qū)地層、天然氣水合物產出帶（the zone of gas hydrate occurrence）或天然氣水合物儲層的地層時代和沉積速率特征，對其中5個站位（GMGS05、GMGS07、GMGS08、GMGS09和GMGS16）的巖心沉積物進行鈣質超微化石、有孔蟲生物地層學和沉積速率變化的研究。鉆孔取心最大深度為213.55 m。共識別出第四紀中更新世以來3個鈣質超微化石事件和2個有孔蟲事件，確定了鉆探區(qū)所鉆達最老地層為中更新統(tǒng)；天然氣水合物產出帶的地層時代為中更新世—全新世約0.44 Ma以來。鉆區(qū)0.12，Ma以來的沉積速率介于36.9～73.3 cm/ka之間，平均值高達54.2 cm/ka，0.44 Ma以來平均沉積速率為47.4 cm/ka，表明東沙海域天然氣水合物鉆探區(qū)位于一高沉積速率堆積體上，高沉積速率更有利于天然氣水合物的成藏，該結論與前人研究結果一致。

關鍵詞：生物地層；沉積速率；中更新世；天然氣水合物鉆區(qū)；南海東北部陸坡

來源出版物：地球科學：中國地質大學學報, 2016 (3):416-424

聯系郵箱：陳芳，Zhchenfang66@21cn.com

青藏高原昆侖山埡口盆地發(fā)現天然氣水合物賦存的證據

吳青柏，蔣觀利，張鵬，等

摘要：青藏高原多年凍土區(qū)是否存在天然氣水合物一直是國內外廣泛關注的問題，但一直沒有確定的答案。通過鉆探、地球物理測井以及氣體地球化學研究，在昆侖山埡口盆地發(fā)現了天然氣水合物賦存的證據。鉆探發(fā)現250 m以下多個深度巖層存在大量氣體釋放異常，甲烷氣體濃度為22%～32%，且具有天然氣水合物分解間歇性釋放的特征，這些氣體釋放層位具有顯著的含天然氣水合物特有的密度降低、側向電阻率和聲波波速的增大特征。同時多個深度上發(fā)現了與水合物分解產生甲烷密切相關的碳酸鹽和黃鐵礦等自生礦物。

關鍵詞：昆侖山埡口盆地；多年凍土；天然氣水合物；地球物理測井異常；氣體釋放

來源出版物：科學通報, 2015 (1): 68-74

聯系郵箱：吳青柏，qbwu@lzb.ac.cn

天然氣水合物熱力學抑制劑作用機制及優(yōu)化設計

趙欣，邱正松，黃維安，等

摘要：基于2種典型天然氣水合物生成預測理論模型，結合水合物熱力學抑制劑評價實驗數據以及水活度測試結果，分析了水合物熱力學抑制劑影響天然氣水合物生成條件的作用機制，建立了水合物生成溫度降低值與水活度的關系式。結果表明，水合物熱力學抑制劑降低水合物生成溫度，或提高水合物生成壓力的作用機制是降低溶液的水活度，其抑制水合物生成效果隨水活度的降低線性增加。通過模擬深水鉆井環(huán)境，對典型的水合物熱力學抑制劑氯化鈉，以及鉆井液常用的有機鹽甲酸鈉進行了水活度測試以及水合物抑制效果評價實驗，探討了可降低鉆井液水活度的有機鹽加重劑 Weigh作為水合物抑制劑的可能性。結果表明，加入氯化鈉或甲酸鈉降低水活度至0.84，鉆井液可在1500 m水深條件下循環(huán)16 h無水合物生成；Weigh可大幅降低溶液水活度，水合物抑制效果優(yōu)于氯化鈉、甲酸鈉以及由氯化鈉和乙二醇組成的復合抑制劑。針對深水鉆完井作業(yè)中遇到的必須使用低密度鉆井液或完井液的情況，初步優(yōu)化設計了低密度水合物抑制劑，可保證鉆井液和完井液在低密度條件下（1.05～1.07 g/cm3）有效抑制水合物生成。

關鍵詞：深水鉆井；天然氣水合物；熱力學抑制劑；預測模型；作用機制；水活度；有機鹽；低密度

來源出版物：石油學報, 2015, 36(6): 760-766

聯系郵箱：邱正松，qiuzs63@sina.com

南海北部神狐海域天然氣水合物鉆探區(qū)第四紀以來的沉積演化特征

蘇明，沙志彬，喬少華，等

摘要：南海北部神狐海域是我國首次獲取海洋天然氣水合物實物樣品的海域。然而，陸坡區(qū)深水水道和海底峽谷的侵蝕以及頻發(fā)的沉積物失穩(wěn)，將會加劇地層對比和沉積相識別的難度，導致目前該區(qū)域典型地震相-沉積相特征、沉積體類型、成因機制和空間匹配關系等方面還缺少精細的研究，特別是第四紀以來的沉積演化涉及較少，區(qū)域內水合物形成和分布的沉積地質條件尚不清晰?；诤５椎匦翁卣鞯拿枋觥有虻貙痈窦艿膶Ρ群偷卣鹳Y料的綜合解釋，本次研究在第四紀以來的沉積充填序列中識別出5種典型的地震相類型，并分析了對應的沉積體類型：進積型的陸坡、第四紀早期發(fā)育的小型濁積水道、沉積物失穩(wěn)（滑移和滑塌）、海底峽谷和伴生的沉積物變形、以及深海沉積-塊體流沉積的復合體。通過沉積單元的空間匹配關系，將沉積演化劃分為3個階段：濁積水道侵蝕-沉積物再沉積階段、陸坡進積-沉積物失穩(wěn)階段、海底峽谷的侵蝕-充填階段。研究結果表明，受第四紀早期小型濁積水道的侵蝕，再沉積的沉積物將在中-下陸坡以“近源”的方式堆積下來，可能具有相對較好的物性條件，從而可被視為適于水合物賦存的有利沉積體。進積型陸坡帶來的沉積物易于發(fā)生失穩(wěn)，在研究區(qū)內廣泛分布，因其具有較小的沉積物顆粒粒度和較好的垂向連續(xù)性，可被認為是水合物的區(qū)域蓋層。大量發(fā)育的海底峽谷及伴生的沉積物變形，將會侵蝕和破壞先前沉積的有利沉積體，使其呈現為“斑狀/補丁狀”的平面展布特征，進而影響了神狐海域水合物的分布。因此，神狐海域第四紀以來的沉積演化是鉆探區(qū)水合物不均勻性分布的關鍵控制因素之一。

關鍵詞：天然氣水合物；地震相；沉積演化；神狐海域天然氣水合物鉆探區(qū)；南海北部

來源出版物：地球物理學報, 2015, 58(8): 2975-2985

聯系郵箱：吳能友，wuny@ms.giec.ac.cn

冷泉形成的數值模擬研究

劉善琪，尹鳳玲，朱伯靖，等

摘要：海底冷泉形成的一種可能機制是海平面下降引起天然氣水合物的分解。本文基于對冷泉滲漏特征的分析，建立了二維軸對稱模型，利用有限元方法定量分析了南海區(qū)域海平面下降對冷泉形成的影響。結果表明，末次冰盛期（26.5～19.0 ka BP）海平面下降引起的冷泉活動可以持續(xù)到現在，但是從水合物停止分解至今，超孔隙壓力的極值在持續(xù)減小，而流體向海底的滲漏達西速度先快速減小、然后緩慢減小。同時發(fā)現，流體向海底的滲漏達西速度與管狀通道的滲透率、通道周圍介質的滲透率以及通道的半徑等有關，估計目前的冷泉活動還可以持續(xù)10000年以上。海平面下降引起的天然氣水合物分解，可能是影響全球氣候變化的一個重要因素。

關鍵詞：天然氣水合物；冷泉；有限元；海平面下降

來源出版物：地球物理學報, 2015, 58(5): 1731-1741

聯系郵箱：李永兵，yongbingli@ucas.ac.cn

來源出版物：Chemical Engineering Science, 2016, 146:199-206

Study on gas hydrate formation and hydrate slurry flow in a multiphase transportation system

Lv, V; Shi, B; Wang, Y; Gong, J; et al.

Abstract: As oil and/or gas exploration and production enter deeper water, the flow assurance confronts challenges, one of which is the hydrate formation and blockage. Investigations about gas hydrate formation and hydrate slurry flow in a multiphase transportation system were performed on a newly constructed high-pressure experimental loop. On the basis of the experimental hydrate formation data, an inward and outward hydrate shell model was improved to predict the gas consumed amount during the hydrate formation process. With the help of a focused beam reflectance measurement and particle video microscope installed in this flow loop, the distribution of hydrate particles was observed,characterized in the coalescence and fragmentation. A“minimum safety flow rate” was first addressed for the safety of hydrate slurry flow in a multiphase transportation system. Then, the comparisons between our experimental data of the natural gas hydrate slurry flow pattern and the Mandhane flow pattern map revealed the influence of hydrate particles on the flow pattern of the slurry.Furthermore, the influence of the gas/liquid superficial velocity on the pressure drop was discussed at stratified flow for this gas hydrate slurry multiphase system.

來源出版物：Energy & Fuels, 2013, 27(12): 7294-7302

An inward and outward natural gas hydrates growth shell model considering intrinsic kinetics,mass and heat transfer

Shi, BH;Gong, J;Sun, CY; et al.

Abstract:The natural gas hydrates formation and growth at 2 MPa and 277.15 K were studied at different water cuts for water-in-condensate oil emulsions in the flow loop unit. The variations of gas consumption with time at different water cuts were obtained. The experimental results showed that the gas consumption value increased with the rise of water cut. The total water conversion rates not only depended on the water cuts, but also related to several other factors, two of which were the amount of the dissolved gas and the surface/volume ratio of the particles.No more natural gas transformed into hydrates after 3 h,which was likely caused by intrinsic kinetics, mass transfer and heat transfer limitations. An inward and outward natural gas hydrates growth shell model was proposed considering all the three limitations to simulate the gas and water consumptions to form natural gas hydrates.

來源出版物：Chemical Engineering Journal, 2011, 171(3):1308-1316

Thermal responses of a gas hydrate-bearing sediment to a depressurization operation

Yamamoto, K; Kanno, T; Wang, XX ; et al.

Abstract:As a part of a research program aiming to mobilize marine gas hydrate deposits as an energy resource, the worlds' first gas production attempt was performed in early 2013 in the Daini Atsumi Knoll,Eastern Nankai Trough, off Honshu Island, Japan. The test concluded with 119000 m3(under ambient conditions) of methane gas production during six consecutive days ofdepressurization operation through a borehole drilled at 1000 m water depth. As thermal and mass transportation in a heterogeneous geological formation are the governing factors of efficiency and effectiveness of the resource,the test was associated with intensive underground temperature monitoring. Temperature sensors installed in one production and two observation boreholes could detect temperature variations during gas production due to the endothermic gas hydrate dissociation process and mass/ heat transport around the boreholes. The measurements in the observation holes started one year before the test and continued until plug-and-abandonment,and thus enabled monitoring of both the initial temperature and temperature change arizing from recovery processes. The depth profiles of measured temperatures in all holes can be related to the geological features of the corresponding formation, and those thermal responses revealed the intervals where gas hydrate dissociation predominantly occurred. By analyzing the energy conservation in the production borehole, the gas and water production profiles could be estimated and major gas and water production zones were identified. Preliminary numerical analysis results show the range of formation permeability and that the observed temperature drop is equivalent to the heat consumption by hydrate dissociation for the volume of produced methane gas. Moreover, the thermal responses could provide some clues about the location and mechanism of the sand production event. This sand production event ultimately terminated the production operations on the seventh day of flow.

來源出版物：RSC Advances, 2017, 7(10): 5554-5577

The i?nik sikumi field experiment, alaska north slope: Design, operations, and implications for CO2–CH4exchange in gas hydrate reservoirs

Ray Boswell; David Schoderbek; Timothy S. Collett; et al.

Abstract: The I?nik Sikumi Gas Hydrate Exchange Field Experiment was conducted by ConocoPhillips in partnership with the U.S. Department of Energy, the Japan Oil, Gas and Metals National Corporation, and the U.S.Geological Survey within the Prudhoe Bay Unit on the Alaska North Slope during 2011 and 2012. The primary goals of the program were to (1) determine the feasibility of gas injection into hydrate-bearing sand reservoirs and(2) observe reservoir response upon subsequent flowback in order to assess the potential for CO2exchange for CH4in naturally occurring gas hydrate reservoirs. Initial modeling determined that no feasible means of injection of pure CO2was likely, given the presence of free water in the reservoir.Laboratory and numerical modeling studies indicated that the injection of a mixture of CO2and N2offered the best potential for gas injection and exchange. The test featured the following primary operational phases: (1) injection of a gaseous phase mixture of CO2, N2, and chemical tracers;(2) flowback conducted at downhole pressures above the stability threshold for native CH4hydrate; and (3) an extended (30-days) flowback at pressures near, and then below, the stability threshold of native CH4hydrate. The test findings indicate that the formation of a range of mixed-gas hydrates resulted in a net exchange of CO2for CH4in the reservoir, although the complexity of the subsurface environment renders the nature, extent, and efficiency of the exchange reaction uncertain. The next steps in the evaluation of exchange technology should feature multiple well applications; however, such field test programs will require extensive preparatory experimental and numerical modeling studies and will likely be a secondary priority to further field testing of production through depressurization. Additional insights gained from the field program include the following: (1) gas hydrate destabilization is self-limiting, dispelling any notion of the potential for uncontrolled destabilization; (2) gas hydrate test wells must be carefully designed to enable rapid remediation of wellbore blockages that will occur during any cessation in operations; (3) sand production during hydrate production likely can be managed through standard engineering controls; and (4) reservoir heat exchange during depressurization was more favorable than expected—mitigating concerns for near-wellbore freezing and enabling consideration of more aggressive pressure reduction.

來源出版物：Energy & Fuels, 2016, 31(1): 140-153

聯系郵箱：Ray Boswell; ray.boswell@netl.doe.gov

High-pressure gas hydrate autoclave hydraulic experiments and scale-up modeling on the effect of stirring RPM effect

Qureshi, MF; Atilhan, M; Altamash, T ; et al.

Abstract:A synthetic quaternary gas mixture (Methane =85.24%, Ethane = 10.03%, n-Hexane = 0.02 mol %, Carbon dioxide = 2.49% and Nitrogen = 2.22%) has been used to study the effect of different stirring rates between 100 and 1400 rotations per minute (RPM) on hydrate crystalformation in the high pressure autoclave cell (HPC). The experimental results obtained show that there exists a threshold limit above and below which hydrate formation decreases drastically. The results were used to determine the optimum-stirring rate at which maximum hydrate crystal formation is obtained in HPC. For the scale up purposes, using the experimental results, the dimensional analysis has been conducted on HPC to obtain optimum power and density ratio factors for the bench scale reactor system. So this work aims to facilitate the ongoing research for using hydrates for natural gas storage and transportation purposes.

關鍵詞：hydrate production; gas transmission and storage;stirring; dimensional analysis

來源出版物：Journal of Natural Gas Science and Engineering, 2017, 38: 50-58

聯系郵箱：Atilhan, M; mert.atilhan@qu.edu.qa

Methane hydrate-liquid-vapour-equilibrium phase condition measurements in the presence of natural amino acids

Bavoh, CB; Partoon, B; Lal, B ; et al.

Abstract:This work reports the thermodynamic effect of five amino acids on methane hydrate phase boundary. The studied amino acids are glycine, alanine, proline, serine and arginine. To effectively investigate the impact of selected amino acids on methane hydrates formation, the methane hydrate-liquid-vapour-equilibrium (HLwVE) curve is measured in amino acids aqueous solutions. Experiments are performed at concentration range of 5 wt%–20 wt% by employing the isochoric T-cycle method in a sapphire hydrate cell reactor at pressures and temperatures range of 3.86–9.98 MPa and 276.50–286.00 K, respectively. Results suggests that, all studied amino acid inhibits methane hydrate formation. Glycine showed the highest inhibition effect with an average depression temperature of 1.78 K at 10 wt%. The impact of inhibition is due to amino acids hydrogen bonding energies, confirmed via COSMO-RS predictions and side group alkyl chain. The inhibition impact of glycine is found to be in the range of some ionic liquid (OH-EMIM-Cl) and slightly higher than ethylene glycol (a conventional thermodynamic hydrate inhibitor) at 10 wt%. The methane hydrate dissociation enthalpies in the presence of amino acids are calculated using Clausius–Clapeyron equation, which suggests that, amino acids do not take part in methane hydrate cage occupation during hydrate formation.

關鍵詞：methane; gas hydrates; amino acids; thermodynamic hydrate inhibitors; HLwVE points

來源出版物：Journal of Natural Gas Science and Engineering, 2017, 37: 425-434

聯系郵箱：Bavoh, CB; bhajan.lal@utp.edu.my

Review of natural gas hydrates as an energy resource: Prospects and challenges

Chong, ZR; Yang, SHB; Babu, P; et al.

Abstract:Natural gas is the cleanest burning fossil fuel and has been identified as a strong candidate for energy resource compared to oil and coal. Natural gas hydrate is an energy resource for methane that has a carbon quantity twice more than all fossil fuels combined and is distributed evenly around the world. Several field trials on energy production from hydrate resources have been conducted, and their outcomes revealed the possibility of energy production from hydrate resources. In this paper,we review various studies on resource potential of natural gas hydrate, the current research progress in laboratory settings, and several recent field trials.Possible limitation in each production method and the challenges to be addressed for large scale production are discussed in detail. Whilst there are no technology stoppers to exploit or produce methane from hydrates,specific technological breakthroughs will depend on the effective management of the sand and water during production, as well as the appropriate mitigation of environmental risks.

關鍵詞：gas hydrates; natural gas; energy recovery;energy resource; methane hydrates;unconventional gas

來源出版物：Applied Energy, 2016, 162: 1633-1652

聯系郵箱：Linga, P; praveen.linga@nus.edu.sg

Rapid methane hydrate formation to develop a cost effective large scale energy storage system

Veluswamy, HP; Wong, AJH; Babu, P; et al.

Abstract:Natural gas (NG) is the cleanest burning fossil fuel and its usage can significantly reduce CO2emissions from power plants. With its widespread use, there is an ever increasing need to develop technologies to store NG on a large scale. NG storage via clathrate hydrates is the best option for a large scale storage system because of its non-explosive nature, mild storage conditions, highvolumetric capacity and being an environmentally benign process. In this work, we demonstrate a new method to achieve rapid methane hydrate formation in an unstirred tank reactor configuration (UTR) at moderate temperature and pressure conditions employing tetrahydrofuran (THF)as a promoter. For the first time, THF is reported to act both as a thermodynamic and an excellent kinetic promoter for methane hydrate formation. We demonstrate a multi-scale experimental validation of our method to a volumetric sample scale-up factor of 120 and internal reactor diameter scale-up factor of 10. Further, new insights on the dissociation behavior of the hydrates are reported. There is a competitive edge for storing NG via clathrate hydrates compared to compressed natural gas storage both in terms of cost and safety.

關鍵詞：gas hydrates; energy storage; tetrahydrofuran;enhanced kinetics; natural gas storage; unstirred tank reactor

來源出版物：Chemical Engineering Journal, 2016, 290:161-173

聯系郵箱：Linga, P; Praveen.Linga@nus.edu.sg

Gas hydrate plug formation in partially-dispersed water–oil systems

Akhfash, M; Aman, ZM; Ahn, SY; et al.

Abstract:The formation of gas hydrate plugs in deep water oil and gas flowlines poses severe operational and safety hazards. Previous work has established a mechanism able to describe plug formation in oil-continuous systems,which relies on the assumption that all the water remains emulsified in the oil phase. However, light hydrocarbon fluids, including condensates, may not stabilize water-in-oil emulsions, and the current mechanistic model cannot reliably assess the risk of plug formation in this scenario. This study presents a comprehensive set of experiments conducted in a high-pressure sapphire autoclave apparatus using 10 vol% to 70 vol% water in partially-dispersing mineral oil at three fixed rotational speeds: 300, 500 and 900 RPM. Pressure and temperature were monitored continuously in the autoclave, providing direct estimates of hydrate growth rate, alongside measurements of the motor torque required to maintain constant mixing speed. A new conceptual mechanism for plug formation has been developed based on the visual observations made during these experiments, where a small hydrate fraction (2 vol%–6 vol%) in the oil phase was observed to disrupt the stratified water–oil interface and help disperse the water into the oil. This disruption was followed by an increase in the hydrate growth rate and particle agglomeration in the oil phase. In the final stages of hydrate growth for systems with low turbulence and high watercut, hydrate particles in the visual autoclave were observed to form a moving bed followed by full dispersion of water and oil, rapid hydrate growth and deposition on the wall. These rapid hydrate growth and deposition mechanisms significantly increased the maximum resistance-to-flow for partially-dispersing systems in comparison with mixtures that are fully dispersed under similar conditions.

關鍵詞：gas hydrates; water-oil emulsion; deposition;partial dispersion; hydrate plug; flow assurance

來源出版物：Chemical Engineering Science, 2016, 140:337-347

聯系郵箱：May, EF; eric.may@uwa.edu.au

Analysis of heat transfer influences on gas production from methane hydrates using a combined method

Song, YC; Wang, JQ; Liu, Y; et al.

Abstract:Heat transfer affects the pressure and temperature distributions of hydrate sediments, thereby controlling hydrate dissociation. Therefore, its study is essential for planning hydrate exploitation. Previously, a two-dimensional axisymmetric model, to investigate the influence of heat transfer on hydrate exploitation from hydrate-bearing sediments, was developed and verified.Here, we extended our investigation to the influence of heat transfer on methane gas production using a combined method coupling depressurization and thermal stimulation.Our simulations showed that during decomposition by the combined method, a high specific heat capacity of the hydrate-bearing porous media or a high initial water content could inhibit gas generation. However, the initial water content had only a weak influence on the cumulative gas production and generation rate. The influence of water and methane heat convection was also weak. An increase of the thermal conductivity initially inhibited hydrate dissociation but later promoted it. The implementation of the combined method increased gas generation compared with using only thermal stimulation. However, the benefits gradually diminished with an increasing heat injection temperature.

關鍵詞：methane hydrate; combined method; conduction;convection; injection temperature; heat transfer

來源出版物：International Journal of Heat and Mass Transfer, 2016, 92: 766-773

聯系郵箱：Zhao, JF; jfzhao@dlut.edu.cn

Evaluation of gas production from methane hydrates using depressurization, thermal stimulation and combined methods

Song, YC; Cheng, CX; Zhao, JF; et al.

Abstract:To investigate the gas production from methane hydrate-bearing sediments, the gas production processes from methane hydrate in porous media using depressurization, two-cycle warm-water injection and a combination of the two methods were characterized in this study. The methane hydrates were formed in porous media with various initial hydrate saturation (Shi) in a pressure vessel. The percentage of gas production, rate of gas production, and energy efficiency were obtained and compared using the three methods. The driving force of the hydrate dissociation at different stages of depressurization was analyzed and ice formation during the gas production was observed. For the two-cycle warm-water-injection method, the percentage of gas production and the energy efficiency increased with increasing of Shi. However, due to the large amount of warm water needed to heat the porous media at the dissociation site, the percentage of gas production was lower than the other two methods under the same experimental conditions. The experimental results proved that the combined method had obvious advantages for hydrate exploitation over the depressurization and warmwater-injection method in terms of the energy efficiency,percentage of gas production and average rate of gas production, and with increasing of Shi, the advantages are enhanced. For the Shiof 51.61%, the percentage of gas production reaches 74.87%, which had increments of 18.63% and 31.19% compared with the depressurization and warm-water-injection methods. The energy efficiency for the combined method were 31.47, 49.93 and 68.13 for Shiof 31.90%, 41.31% and 51.61%, respectively.

關鍵詞：methane hydrate-bearing sediments; energy efficiency; depressurization; thermal injection; combination production; buffer effect

來源出版物：Applied Energy, 2015, 145: 265-277

聯系郵箱：Zhao, JF; jfzhao@dlut.edu.cn

Mechanical properties of hydrate-bearing turbidite reservoir in the first gas production test site of the Eastern Nankai Trough

Yoneda, J; Masui, A; Konno, Y; et al.

Abstract:The study of mechanical properties of marine sediments is essential for the prediction of the occurrence of geohazards (e.g., subsea landslides and seafloor subsidence) and the design of submarine structures for offshore industry. In this study, triaxial compression tests of gas-hydrate-bearing sandy sediments and clayey-silty sediments were conducted. The sediments were recovered by pressure coring in the Eastern Nankai Trough, the area of the first Japanese offshore production test. Soil index properties were measured and revealed porosity of 40%–50%, with porosity decreasing gradually with greater depth below the seafloor. The mean particle size was less than 10 μm for clayey-silty sediments and approximately 100 μm for sandy sediments. Permeability, estimated by a consolidation process of triaxial testing and with X-ray diffraction analysis, depended on the content of fines,which consisted chiefly of mica, kaolinite, and smectite.The results of undrained compression tests for clayey-silty sediments showed positive excess pore pressure under all test conditions. This mechanical behavior indicates that the core samples are normally consolidated sediments. Drained compression tests showed that the strength and stiffness of sandy sediments increase with hydrate saturation.Furthermore, the volumetric strain of hydrate-bearing sediments changed from compression to dilative. This result was obtained for hydrate saturation values (Sh) of more than 70%. The shear strength of hydrate-bearing turbidite sediments of the Eastern Nankai Trough is shown to be a function of the confining pressure.

關鍵詞：hydrate-bearing sand; triaxial test; pressure core;mechanical property; hydrate saturation

來源出版物：Marine and Petroleum Geology, 2015, 66:471-486

聯系郵箱：Yoneda, J; jun.yoneda@aist.go.jp

編輯：王微

Investigation of natural gas hydrate slurry flow properties and flow patterns using a high pressure flow loop

Ding, L; Shi, B; Lv, X; et al.

The formation and agglomeration of hydrates have been a major hazard to the operating safety ofdeep-sea oil/gas transportation pipeline. Although many studies have been conducted to investigate the hydrates formation and particle behaviors during the transportation,studies on the gas–slurry flow properties and effects of hydrates on multiphase flow patterns are still almost blank. In this work, a series of experiments were conducted in a high pressure flow loop, using the materials of a pseudo single-liquid-phase (saturated water/oil emulsion) and a gas–liquid multiphase, respectively. It was found that hydrates agglomeration was more violent and the flow property was worse in the gas–liquid multiphase system. When hydrates formed in the gas–liquid multiphase system, the liquid flow rate would decrease in all experimental conditions while the gas flow rate showed three different changing types: decreasing,increasing or keeping constant. These changes of the flow rate would further induce a transition of the gas–liquid multiphase flow pattern in the loop. Based on the experimental data, two flow pattern maps were made. One involved the effects of hydrates while the other did not.Through the comparison between the two flow pattern maps, it is confirmed that the influence of hydrates on the flow pattern is significant. The differences between the two flow pattern maps were also analyzed using a flow pattern transition model to provide an insight into the mechanism of how hydrates affect the multiphase flow pattern.