scholarly journals Overview and prospect of fracture propagation and conductivity characteristics in deep shale gas wells

2017 ◽  
Vol 47 (11) ◽  
pp. 114603 ◽  
Author(s):  
TingXue JIANG ◽  
Jian ZHOU ◽  
Xu ZHANG ◽  
Lei HOU ◽  
Bo XIAO
Keyword(s):  
Shale Gas ◽  
Fracture Propagation ◽  
Gas Wells

scholarly journals Alkali Solution Erodes Shale: Influencing Factors and Structural Damage Characteristics

2018 ◽  
Vol 2018 ◽  
pp. 1-8
Author(s):  
Jiping She ◽  
Hao Zhang ◽  
Ying Zhong ◽  
Yang Yuan ◽  
Jiachun You
Keyword(s):  
Corrosion Rate ◽  
Shale Gas ◽  
Structural Damage ◽  
Reaction Rate ◽  
Fracture Propagation ◽  
Drilling Fluids ◽  
Gas Wells ◽  
Wellbore Instability ◽  
High Ph ◽  
Bedding Planes

High-pH drilling fluids are often used for drilling shale gas wells. Alkali erosion of shale is one of the important factors of wellbore instability. Alkali erosion experiments of different kinds of minerals and shale were conducted in this paper. Experimental results show that the corrosion rate of kaolinite is the highest when the pH is 9, the corrosion rate of smectite is the highest when the pH is 10 or 11, and the corrosion rate of the quartz is the highest when the pH is 12. Both shale particle size and concentration of hydroxide ion all affect the reaction rate, and the former has a negative correlation with the reaction rate, and the latter has a positive correlation with the reaction rate. In addition, alkaline erosion can lead to the fracture propagation along the bedding planes of shale, which can easily result in wellbore instability. This study may offer some theoretical basis for wellbore instability induced by high-pH drilling fluids.

A Methodology to Quantify the Volume-of-investigation in DFIT Design for Shale Gas Wells

2019 ◽  
Author(s):  
Zhiming Chen ◽  
Hongyang Chu ◽  
Xuefeng Tang ◽  
Lingyu Mu ◽  
Peng Dong ◽  
...  
Keyword(s):  
Shale Gas ◽  
Gas Wells

scholarly journals Integrity tests of cement sheath for shale gas wells under strong alternating thermal loads

2020 ◽  
Vol 7 (6) ◽  
pp. 671-679
Author(s):  
Yuanhua Lin ◽  
Kuanhai Deng ◽  
Hao Yi ◽  
Dezhi Zeng ◽  
Liang Tang ◽  
...  
Keyword(s):  
Shale Gas ◽  
Thermal Loads ◽  
Gas Wells ◽  
Cement Sheath ◽  
Integrity Tests

Lithology and sedimentary heterogeneity of the Longmaxi Shale in the southern Sichuan Basin, China

2021 ◽  
pp. 1-49
Author(s):  
Boling Pu ◽  
Dazhong Dong ◽  
Ning Xin-jun ◽  
Shufang Wang ◽  
Yuman Wang ◽  
...  
Keyword(s):  
Continental Shelf ◽  
Deep Water ◽  
Shale Gas ◽  
Sichuan Basin ◽  
Sedimentary Environment ◽  
Gas Production ◽  
Carbonaceous Shale ◽  
Gas Wells ◽  
Longmaxi Shale ◽  
Siliceous Shale

Producers have always been eager to know the reasons for the difference in the production of different shale gas wells. The Southern Sichuan Basin in China is one of the main production zones of Longmaxi shale gas, while the shale gas production is quite different in different shale gas wells. The Longmaxi formation was deposited in a deep water shelf that had poor circulation with the open ocean, and is composed of a variety of facies that are dominated by fine-grained (clay- to silt-size) particles with a varied organic matter distribution, causing heterogeneity of the shale gas concentration. According to the different mother debris and sedimentary environment, we recognized three general sedimentary subfacies and seven lithofacies on the basis of mineralogy, sedimentary texture and structures, biota and the logging response: (1) there are graptolite-rich shale facies, siliceous shale facies, calcareous shale facies, and a small amount of argillaceous limestone facies in the deep - water shelf in the Weiyuan area and graptolite-rich shale facies and carbonaceous shale facies in the Changning area; (2) there are argillaceous shale facies and argillaceous limestone facies in the semi - deep - water continental shelf of the Weiyuan area and silty shale facies in the Changning area; (3) argillaceous shale facies are mainly developed in the shallow muddy continental shelf in the Weiyuan area, while silty shale facies mainly developed in the shallow shelf in the Changning area. Judging from the biostratigraphy of graptolite, the sedimentary environment was different in different stages.

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