Characteristics of Gas Hydrate Stability Zone in The Muli Permafrost, Qinghai: Results Compared Between Modeling and Drilling

Chunshuang, Jin; De-wu, Qiao; Lü, Zeng; Zhu, Yefei; Zhang, Yongqin; Wen, Huaijun; Li, Yonghong; Wang, Pingkang; Hu, Xia

doi:10.1002/cjg2.1585

Cited by 12 publications

(11 citation statements)

References 10 publications

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“…It shows that the top and bottom depth of the hydrate stability zone calculated by data of real gas composition and temperature of drilling mud are comparable with the yield depth of hydrate and its anomalies revealed by drilling. The top depth and bottom depth of the hydrate stability zone by modeling are respectively 148.8 m to 122.7 m and 324.6 m to 354.8 m and the thickness of gas hydrate bearing sediments is 175.8 m to 232.2 m. The interval of hydrate and its anomalies revealed by drilling is 133 m to 396 m [33] . These two results are basically same, which proves that the empirical model is applicable.…”

Section: Conclusion and Discussionmentioning

confidence: 95%

Modeling Effects of Gas Sources on Gas Hydrate Formation in the Northern South China Sea

Lü

Jia-xiong

Chunshuang

et al. 2013

Chinese J of Geophysics

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Geological factors affecting gas hydrate formation and distribution are different horizontally and vertically in the northern slope of the South China Sea such as the Shenhu area. Whether variation of gas sources is an important resultant factor is worth exploring. In this paper, 14 cases of gas source are summarized on the base of existing data and a semi‐quantitative analysis is conducted by modeling to study their effects on gas hydrate formation in the northern South China Sea. Modeling results show that various gas sources will enhance temperature conditions for gas hydrate formation by 0.49°C to 5.44°C, mostly by more than 2°C, with respect to known gas hydrate in the Shenhu area. This indicates that various gas sources greatly change gas hydrate formation conditions, suggesting that they are probably important factors to affect gas hydrate formation and distribution in the northern South China Sea.

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Section: Conclusion and Discussionmentioning

confidence: 95%

Modeling Effects of Gas Sources on Gas Hydrate Formation in the Northern South China Sea

Lü

Jia-xiong

Chunshuang

et al. 2013

Chinese J of Geophysics

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“…The part with the steeper slope denotes a lower geothermal gradient, while the other part of the curve that is less steep represents the strata beneath the frozen soil. This means that the geothermal gradient is higher in the underlaying strata compared to that in the frozen soil. , The inflection point where these two sections of the curve connect represents the bottom depth of the frozen soil, where the formation temperature is 0 °C. The thickness of the frozen soil determines the vertical extension of the formation temperature curve.…”

Section: Discussionmentioning

confidence: 99%

Theoretical Prediction of the Occurrence of Gas Hydrate Stability Zones: A Case Study of the Mohe Basin, Northeast China

et al. 2021

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Source rocks of the Mohe Basin, Northeast China are gas-prone and the organic matter has advanced to late oil-generation stages, producing condensate and natural gas. This provides suitable conditions for the Mohe Basin to become one of the most prolific terrestrial natural gas hydrate (NGH)-bearing areas in China. Knowing this, here we predict the depth and thickness of pure methane hydrate stability zones (HSZs) and gas hydrate stability zones (GHSZs) via simulating the hydrate-phase equilibrium and other formation P – T conditions. Furthermore, factors that have a major impact on the occurrence of HSZs are discussed. Results showed that the composition of gas (guest) molecules and the geothermal gradient are the two most controlling factors on HSZs. Moreover, it was found that a pure methane HSZ with a thickness of about 255 m can form in areas with a geothermal gradient of <1.5 °C/100 m, with top and bottom depth limits less than 493 m and greater than 748 m, respectively. In contrast, pure methane hydrates have difficulty forming, while hydrates from wet gas can form where there is a geothermal gradient of >1.6 °C/100 m. Furthermore, a wet gas HSZ with a thickness of at least 735 m can be expected when the geothermal gradient reaches 2.3 °C/100 m, with top and bottom depth limits at 115 and 850 m, respectively. Ultimately, a pure methane HSZ can still form in the abnormally high-pressured areas when the geothermal gradient is up to 2.0 °C/100 m. Overall, HSZs can occur due to the combined effect of formation temperature, pressure, and gas composition. Finally, based on the results from this study and drilling data, future successful hydrate drilling schemes can be implemented in the Mohe Basin and similar terrestrial areas.

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“…As a result, there has been a marked acceleration of studies in evaluating the technical and economic feasibility of gas production from natural hydrate accumulations. As early as in 1967, the former Soviet for the first time discovered its permafrost gas hydrate in the course of developing the Messoyakha gas field in the western Siberian. , In 1972, the researchers in Northwest Eileen State-02 (NWE-2) well on the Alaska North Slope confirmed the presence of gas hydrate in the permafrost region . In 1998, the Japanese cooperated with Canada and discovered 37 m depth of hydrate cores when drilling 890–952 m in the Mackenzie delta in Canada .…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation of Gas Production from Natural Gas Hydrate Using a Single Horizontal Well by Depressurization in Qilian Mountain Permafrost

Yang

et al. 2012

Ind. Eng. Chem. Res.

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In November 2008, gas hydrate samples were recovered during the scientific expedition conducted in the Qilian Mountain Permafrost. It is expected that this area will become a strategic area of gas hydrate production in China. However, the evaluation of the hydrate deposits in the area as a potential energy resource has not been completed. Using numerical simulation and currently available data from site measurements, we preliminarily estimate the gas production potential of these hydrate reservoirs. The cumulative volume of the produced CH 4 at the well in the early production period (0−10 years) is more than 50% of the total gas production from the well. The gas hydrate dissociation mainly occurs in the vicinity of the horizontal well and along a cylindrical interface. There is a ringlike structure of ice around the horizontal well during the gas production process. With the decrease of the gas production rate, the ice starts to melt from the bottom to the top under the influence of the geothermal gradient. The sensitivity analysis demonstrates the dependence of production on the intrinsic permeability and the initial deposit temperature. Economic assessment based on the cumulative volumetric gas production and the gas-to-water ratio indicates that it is not economically viable to produce gas from this hydrate deposit using single horizontal well by depressurization.

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Characteristics of Gas Hydrate Stability Zone in The Muli Permafrost, Qinghai: Results Compared Between Modeling and Drilling

Cited by 12 publications

References 10 publications

Modeling Effects of Gas Sources on Gas Hydrate Formation in the Northern South China Sea

Modeling Effects of Gas Sources on Gas Hydrate Formation in the Northern South China Sea

Theoretical Prediction of the Occurrence of Gas Hydrate Stability Zones: A Case Study of the Mohe Basin, Northeast China

Numerical Simulation of Gas Production from Natural Gas Hydrate Using a Single Horizontal Well by Depressurization in Qilian Mountain Permafrost

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