scholarly journals Transient dynamics study on casing deformation resulted from lost circulation in low-pressure formation in the Yuanba Gasfield, Sichuan Basin

2015 ◽  
Vol 2 (4) ◽  
pp. 347-353 ◽  
Author(s):  
Chen Shen
Keyword(s):  
Sichuan Basin ◽  
Low Pressure ◽  
Transient Dynamics ◽  
Lost Circulation ◽  
Casing Deformation

scholarly journals An Integrated Method for Evaluating Lost Circulation Risk for Shale Gas Drilling in Sichuan Basin

2021 ◽  
Vol 861 (6) ◽  
pp. 062075
Author(s):  
Rong-Chao Cheng ◽  
Ming-Ming Chu ◽  
Jie Zhang ◽  
Hui-Jiun Hao ◽  
Hai Lin ◽  
...  
Keyword(s):  
Shale Gas ◽  
Sichuan Basin ◽  
Lost Circulation ◽  
Integrated Method ◽  
Gas Drilling ◽  
Shale Gas Drilling

scholarly journals Numerical Study of a Southwest Vortex Rainstorm Process Influenced by the Eastward Movement of Tibetan Plateau Vortex

2018 ◽  
Vol 2018 ◽  
pp. 1-10
Author(s):  
Xiaoli Liu ◽  
Endian Ma ◽  
Zhibin Cao ◽  
Shuanglong Jin
Keyword(s):  
Tibetan Plateau ◽  
Sichuan Basin ◽  
Low Pressure ◽  
Ice Crystals ◽  
The Tibetan Plateau ◽  
Pressure System ◽  
Convective Clouds ◽  
Low Pressure System ◽  
Southwest Vortex ◽  
The Sichuan Basin

A number of studies revealed the possible eastward movement of the Tibetan Plateau low-pressure system in summer and indicated the enhancement effect of this process on the southwest vortex in the Sichuan Basin, which can induce strong convective precipitation and flood events in China. In this study, a numerical simulation of a southwest vortex rainstorm process was performed. The results show that the low-pressure system originated from the Tibetan Plateau affects the southwest vortex mainly at the middle level, causing the strength increase of southwest vortex (SWV), and acts as a connection between the positive vorticity centers at the upper and lower layers. For the microscopic cloud structure, the vertical updraft of the cloud cluster embedded in the SWV increases as the low-pressure system from the plateau arrives at the Sichuan Basin. Vapor and liquid cloud water at the lower level are transported upward, based on which the ice cloud at the upper level and the warm cloud at the lower level are joined to create favorable conditions for the growth of ice crystals. As the ice crystals grow up, snow and graupel particles form, which substantially elevates the precipitation. This effect leads to the rapid development of SWV rainstorm clouds and the occurrence of precipitation. In addition to the effect of the plateau vortex, the subsequent merging of the convective clouds is another important factor for heavy rainfall because it also leads to development of convective clouds, causing heavy rainfall.

scholarly journals Organic Matter Pore Characterization of the Wufeng-Longmaxi Shales from the Fuling Gas Field, Sichuan Basin: Evidence from Organic Matter Isolation and Low-Pressure CO2 and N2 Adsorption

Energies ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1207 ◽  
Author(s):  
Zhuo Li ◽  
Zhenxue Jiang ◽  
Hailong Yu ◽  
Zhikai Liang
Keyword(s):  
Organic Matter ◽  
Pore Volume ◽  
Sichuan Basin ◽  
Weight Ratio ◽  
Total Pore Volume ◽  
Low Pressure ◽  
N2 Adsorption ◽  
Sem Images ◽  
Gas Field ◽  
Flow Mechanisms

Organic matter (OM) pores are significant for shale gas accumulation and flow mechanisms. The pores of Wufeng-Longmaxi (W-L) shale in the Sichuan Basin, China have been extensively characterized, however, the proportion of OM pores in this shale have not been adequately discussed. In this study, the contribution of OM pores to the total pore volume of W-L shale was quantitatively studied through the analysis of OM isolation, field emission scanning electron microscopy (FE-SEM) and low-pressure CO2 and N2 adsorption (LPGA). FE-SEM images showed abundant OM pores, interparticle pores and intraparticle pores with various shapes and widths in the W-L shales. The pore size distribution (PSD) of the isolated OM from five shale samples showed a consistent, unimodal pattern. The pore volume of isolated OM was greater than that of the bulk shale samples, suggesting that OM is more porous than the inorganic compositions in shales. The average contribution of OM to the volumes of micropores, mesopores and macropores was 58.42%, 10.34% and 10.72%, respectively. Therefore, the pore volume of the W-L shale was dominantly related to inorganic minerals. This was probably due to the small weight ratio of OM in the shale samples (1.5 wt%–4.2 wt%). The findings of this study reveal the different effects of OM and minerals on pore development, and provide new insights into the quantitative contribution of OM pores to the total pore volume of the W-L shale.

Influence of the synoptic systems and inversion characteristics on winter heavy air pollution in the lower atmosphere over Sichuan Basin, China

2020 ◽  
Author(s):  
Shigong Wang ◽  
Hua Fu
Keyword(s):  
Air Pollution ◽  
Sichuan Basin ◽  
Low Pressure ◽  
Urban Agglomeration ◽  
Lower Atmosphere ◽  
Horizontal Wind ◽  
Pressure System ◽  
Low Pressure System ◽  
The Sichuan Basin ◽  
Pollution Events

<p>The Sichuan Basin is located in the eastern part of the Tibetan Plateau, and there is a rapidly developing urban agglomeration over there. Therefore, heavy air pollution events have frequently occurred over many cities in recent decades. In this study, We explored the effects of weather systems on winter heavy air pollution from more than 10 cases of heavy air pollution events occurred during 2006-2018. Most of them were affected by a dry low-pressure system at 700 hPa, at the same time , they were also influenced by the inversion with several layers in the lower atmosphere. It is interesting that the synergistic effects of synoptic patterns and inversions caused by topography on heavy air pollution events. When the urban agglomeration was in front of the low-pressure system and the weather conditions were controlled by a warm southerly air flow, a strong temperature inversion appeared above the atmospheric boundary layer acting as a lid. The local secondary circulation was forced by both of them and was confined within the atmospheric boundary layer. At that time, the horizontal wind speed in the lower atmosphere was low.  As a result, vertical mixing and horizontal dispersion in the atmosphere were poor, a heavy air pollution event was gradually caused. After the low-pressure system had passed over the urban agglomeration, the weather conditions over there were controlled by a dry and cold air flow from the northwest at 700 hPa, foregoing strong inversion layer gradually dissipated, the secondary circulation enhanced and uplifted, and the horizontal wind speed in the lower atmosphere also increased, resulting in a sharp decrease in the concentration of air pollutants. In sum, the strong inversion layers above the lower atmosphere were induced by the low-pressure systems at 700 hPa, both happened a synergistic effect and played a key role in the formation of heavy air pollution during the winter months in this urban agglomeration of The Sichuan Basin. Finally, it was presented that a new conceptual model is about meteorological causes of winter heavy air pollution  in the Sichuan Basin.</p>

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