The second natural gas hydrate production test in the South China Sea

Ye, Jian-liang; Qin, Xuwen; Xie, Wenwei; Lu, Hailong; Ma, Baojin; Qiu, Haijun; Jiang, Liang; Lu, Jing; Kuang, Zenggui; Lü, Cheng; Liang, Qianyong; Wei, Shi-peng; Yu, Yanjiang; Liu, Chunsheng; Li, Bin; Shen, Kaixiang; Shi, Hao-xian; Lu, Qiuping; Li, Jing; Kou, Bei-bei; Song, Gang; Li, Bo; Zhang, Heen; Lu, Hongfeng; Ma, Chao; Dong, Yifei; Bian, Hang

doi:10.31035/cg2020043

Cited by 451 publications

(283 citation statements)

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“…This hydrate-forming source gas originates from the deeper sedimentary sequences (source rocks of feed gas) and has been formed by thermogenic activities [20,21], such as thermal cracking [22]. Thermogenic CH 4 has not only been found within Arctic circumpolar GH accumulations in the Beaufort Sea and Russia [8], but also at the thermogenic basins lying between upper continental slopes and deep water sags, such as the Gulf of Mexico [23] and the South China Sea [24,25].…”

Section: Introduction 1arctic Permafrost-associated Gas Hydratesmentioning

confidence: 99%

Numerical Simulation of Coastal Sub-Permafrost Gas Hydrate Formation in the Mackenzie Delta, Canadian Arctic

Spangenberg

Schicks

et al. 2022

Energies

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The Mackenzie Delta (MD) is a permafrost-bearing region along the coasts of the Canadian Arctic which exhibits high sub-permafrost gas hydrate (GH) reserves. The GH occurring at the Mallik site in the MD is dominated by thermogenic methane (CH4), which migrated from deep conventional hydrocarbon reservoirs, very likely through the present fault systems. Therefore, it is assumed that fluid flow transports dissolved CH4 upward and out of the deeper overpressurized reservoirs via the existing polygonal fault system and then forms the GH accumulations in the Kugmallit–Mackenzie Bay Sequences. We investigate the feasibility of this mechanism with a thermo–hydraulic–chemical numerical model, representing a cross section of the Mallik site. We present the first simulations that consider permafrost formation and thawing, as well as the formation of GH accumulations sourced from the upward migrating CH4-rich formation fluid. The simulation results show that temperature distribution, as well as the thickness and base of the ice-bearing permafrost are consistent with corresponding field observations. The primary driver for the spatial GH distribution is the permeability of the host sediments. Thus, the hypothesis on GH formation by dissolved CH4 originating from deeper geological reservoirs is successfully validated. Furthermore, our results demonstrate that the permafrost has been substantially heated to 0.8–1.3 °C, triggered by the global temperature increase of about 0.44 °C and further enhanced by the Arctic Amplification effect at the Mallik site from the early 1970s to the mid-2000s.

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Section: Introduction 1arctic Permafrost-associated Gas Hydratesmentioning

confidence: 99%

Numerical Simulation of Coastal Sub-Permafrost Gas Hydrate Formation in the Mackenzie Delta, Canadian Arctic

Spangenberg

Schicks

et al. 2022

Energies

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“…In 2017 and 2020, two rounds of NGH production tests were conducted in the Shenhu area in the South China Sea. Field testing shows that the water depth is approximately 1266 m, and the NGH mainly occurs at 201-278 m below the seabed mudline with a total thickness of 77 m. The reservoir can be separated as three layers [35,44]: (1) the NGH-bearing layer, approximately 35 m thick (Hydrate saturation, about 30%); (2) the three-phase mixed layer, about 15 m thick; (3) the free gas layer, about 27 m thick. The hydrate is mainly the type of pore filling.…”

Section: Modelling 21 Geological Backgroundmentioning

confidence: 99%

“…Meanwhile, the sensitivity analysis of drilling parameters has also been studied by scholars [32][33][34]. In 2020, China Geological Survey (CGS) explored horizontal well to extract NGH in deep-sea soft reservoir for the first time in the world, making a significant leap from "exploratory production" to "experimental production" [35]. The results showed that compared with the vertical well, the horizontal well significantly improved gas production and has great developmental potential and economic potential for improving the natural gas hydrate production capacity [36].…”

Section: Introductionmentioning

confidence: 99%

Effect of Drilling Fluid Invasion on Natural Gas Hydrate Near-Well Reservoirs Drilling in a Horizontal Well

et al. 2021

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Horizontal wells can significantly improve the gas production and are expected to be an efficient exploitation method for the industrialization of natural gas hydrates (NGHs) in the future. However, the near-wellbore hydrate is highly prone to decomposition during the drilling process, owing to the disturbance aroused by the factors such as the drilling fluid temperature, pressure, and salinity. These issues can result in the engineering accidents such as bit sticking and wellbore instability, which are required for further investigations. This paper studies the characteristics of drilling fluid invasion into the marine NGH reservoir with varied drilling fluid parameters via numerical simulation. The effects of the drilling fluid parameters on the decomposition behavior of near-wellbore hydrates are presented. The simulating results show that the adjustments of drilling fluid density within the mud safety window have limited effects on the NGH decomposition, meanwhile the hydrates reservoir is most sensitive to the drilling fluid temperature variation. If the drilling fluid temperature grows considerably due to improper control, the range of the hydrates decomposition around the horizontal well tends to expand, which then aggravates wellbore instability. When the drilling fluid salinity varies in the range of 3.5–7.5%, the increase in the ion concentration speeds up the hydrate decomposition, which is adverse to maintaining wellbore stability.

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“…As an unconventional natural gas resource, natural gas hydrate (NGH) has been found vastly distributed in the permafrost or beneath the shallow seabed, and is regarded as an alternative energy in the future 1,2 . The trial productions in Russia, Canada, United States, Japan, and China have demonstrated the technical feasibility of NGH production 3–6 . It has been reported that more than 90% of the global NGH resources are in clayey silts 7 .…”

Section: Introductionmentioning

confidence: 99%

“…1,2 The trial productions in Russia, Canada, United States, Japan, and China have demonstrated the technical feasibility of NGH production. [3][4][5][6] It has been reported that more than 90% of the global NGH resources are in clayey silts. 7 During the NGH production, the dissociation is inevitably involved.…”

Section: Introductionmentioning

confidence: 99%

Experimental investigation and modeling on the dissociation conditions of methane hydrate in clayey silt cores

Sun

Yang

et al. 2022

AIChE Journal

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As the majority of global natural gas hydrate reserve, the dissociation conditions of hydrate in clayey silts are of great significance for its efficient production. In this work, the dissociation conditions of methane hydrate in clayey silt cores were experimentally measured by step-heating method at the temperature range of 280.76-289.55 K and pressure range of 8.11-15.03 MPa, respectively. Various cores including quartz powder, montmorillonite, and South China Sea sediments at the water content range of 20%-33% were used for investigation. The results showed that the dissociation temperatures of methane hydrate in clayey silt cores depressed compared to bulk hydrate. The grain size, salinity, and lithology of clayey silt cores significantly affect the dissociation conditions of hydrate. In comparison to grain size, salinity, and lithology had a more significant influence on the equilibrium temperature depression.The dissociation temperature depression of methane hydrate was considered as a consequence of the water activity depression which is caused by the effect of capillary, salt, or clay. A water activity meter was used to measure the water activity in clayey silt cores. The influence of salt component and mineral characteristics on the water activity was investigated. By combining the measured water activity data with the Chen-Guo model, a novel water activity measurement (WAM) method for the hydrate dissociation conditions prediction was proposed. With the maximum deviation less than 12%, the predicted results are in good agreement with the experimental data. It demonstrated that the WAM method could effectively predict the dissociation conditions of methane hydrate in clayey silts with convenience and accuracy.

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The second natural gas hydrate production test in the South China Sea

Cited by 451 publications

References 0 publications

Numerical Simulation of Coastal Sub-Permafrost Gas Hydrate Formation in the Mackenzie Delta, Canadian Arctic

Numerical Simulation of Coastal Sub-Permafrost Gas Hydrate Formation in the Mackenzie Delta, Canadian Arctic

Effect of Drilling Fluid Invasion on Natural Gas Hydrate Near-Well Reservoirs Drilling in a Horizontal Well

Experimental investigation and modeling on the dissociation conditions of methane hydrate in clayey silt cores

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