Wide Field Electromagnetic Method for Shale Gas Exploration in Southern China: A Case Study

2017 ◽  
Vol 22 (3) ◽  
pp. 279-289 ◽  
Author(s):  
Bo Yuan ◽  
Diquan Li ◽  
Richard C. Bayless
Keyword(s):  
Shale Gas ◽  
Southern China ◽  
Electromagnetic Method ◽  
Wide Field

Application of a wide-field electromagnetic method to shale gas exploration in South China

2017 ◽  
Vol 14 (3) ◽  
pp. 441-448 ◽  
Author(s):  
Xue-Li Yang ◽  
Bo Li ◽  
Chuan-Sheng Peng ◽  
Yang Yang
Keyword(s):  
South China ◽  
Shale Gas ◽  
Electromagnetic Method ◽  
Wide Field

Application of wide-field electromagnetic method in shale gas survey in Eastern Kunlun, Qinghai province, China

2020 ◽  
Vol 27 (11) ◽  
pp. 3388-3397
Author(s):  
Zhong-hong Yu ◽  
Ling-qin Yan ◽  
Zhi-jie Cai ◽  
Jin-hai Wang ◽  
Yong-feng Xu ◽  
...  
Keyword(s):  
Shale Gas ◽  
Electromagnetic Method ◽  
Wide Field ◽  
Qinghai Province

Evaluation of the exploration prospect and risk of marine gas shale, southern China: A case study of Wufeng-Longmaxi shales in the Jiaoshiba area and Niutitang shales in the Cen’gong area

2021 ◽  
Author(s):  
Qiyang Gou ◽  
Shang Xu ◽  
Fang Hao ◽  
Yangbo Lu ◽  
Zhiguo Shu ◽  
...  
Keyword(s):  
Shale Gas ◽  
Southern China ◽  
Hydrocarbon Generation ◽  
Material Base ◽  
Pore Connectivity ◽  
Significant Difference ◽  
Dip Angle ◽  
Angle Fractures ◽  
Hydrothermal Activities

The Wufeng-Longmaxi shales and the Niutitang shales are the most important organic-rich marine shales in southern China. To fully understand the significant difference in drilling results between the two sets of shales, the accumulation conditions of shale gas were systematically compared. The Niutitang shales have a superior material base of hydrocarbon generation for higher total organic carbon than the Wufeng-Longmaxi shales. Due to the influence of hydrothermal activities and carbonization of organic matter, however, the porosity, pore volume, pore size, and pore connectivity of Niutitang shales is obviously lower than that of Wufeng-Longmaxi shales. The natural fractures of Wufeng-Longmaxi shales are dominated by horizontal bedding fractures, and most of them are filled by calcite. By contrast, the high dip-angle fractures are more developed in the Niutitang shales. Especially, these fractures remain open in stages during the process of serious uplift and denudation movements. Thus, the seal conditions of the Niutitang shales are poor, which is further not conducive to the enrichment of shale gas. Our work also suggests that the exploration and development of highly over matured marine shales in southern China should follow the principle of “high to find low, and strong to find weak.”

Solidifying Mud Cake to Improve Cementing Quality of Shale Gas Well: A Case Study

2015 ◽  
Vol 8 (1) ◽  
pp. 149-154 ◽  
Author(s):  
Jun Gu ◽  
Ju Huang ◽  
Su Zhang ◽  
Xinzhong Hu ◽  
Hangxiang Gao ◽  
...  
Keyword(s):  
Shale Gas ◽  
Calcium Silicate Hydrate ◽  
Drilling Fluid ◽  
Cement Slurry ◽  
Gas Well ◽  
Safety Requirements ◽  
Mud Cake ◽  
Gas Bearing

The purpose of this study is to improve the cementing quality of shale gas well by mud cake solidification, as well as to provide the better annular isolation for its hydraulic fracturing development. Based on the self-established experimental method and API RP 10, the effects of mud cake solidifiers on the shear strength at cement-interlayer interface (SSCFI) were evaluated. After curing for 3, 7, 15 and 30 days, SSCFI was remarkably improved by 629.03%, 222.37%, 241.43% and 273.33%, respectively, compared with the original technology. Moreover, the compatibility among the mud cake solidifier, cement slurry, drilling fluid and prepad fluid meets the safety requirements for cementing operation. An application example in a shale gas well (Yuanye HF-1) was also presented. The high quality ratio of cementing quality is 93.49% of the whole well section, while the unqualified ratio of adjacent well (Yuanba 9) is 84.46%. Moreover, the cementing quality of six gas-bearing reservoirs is high. This paper also discussed the mechanism of mud cake solidification. The reactions among H3AlO42- and H3SiO4- from alkali-dissolved reaction, Na+ and H3SiO4- in the mud cake solidifiers, and Ca2+ and OH- from cement slurry form the natrolite and calcium silicate hydrate (C-S-H) with different silicate-calcium ratio. Based on these, SSCFI and cementing quality were improved.

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