Interaction mechanism and development suggestions for the full cycle construction effect of surface horizontal wells in unmined coal mines

To explore the differences in fracturing effects of different levels of ground level wells in unmined coal mines, and to reveal the interaction mechanism of construction effects in various stages of gas control throughout the entire cycle, combined with the construction status of ZJ2−1 and ZJ2−2 wel...

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Main Authors: Zhainan ZHANG, Ke YANG, Xinzhu HUA, Chunhui YE, Min YE, Wenjie LIU, Xiaolou CHI, Xin LYU
Format: Article
Language:zho
Published: Editorial Department of Coal Science and Technology 2025-03-01
Series:Meitan kexue jishu
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Online Access:http://www.mtkxjs.com.cn/article/doi/10.12438/cst.2024-1136
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author Zhainan ZHANG
Ke YANG
Xinzhu HUA
Chunhui YE
Min YE
Wenjie LIU
Xiaolou CHI
Xin LYU
author_facet Zhainan ZHANG
Ke YANG
Xinzhu HUA
Chunhui YE
Min YE
Wenjie LIU
Xiaolou CHI
Xin LYU
author_sort Zhainan ZHANG
collection DOAJ
description To explore the differences in fracturing effects of different levels of ground level wells in unmined coal mines, and to reveal the interaction mechanism of construction effects in various stages of gas control throughout the entire cycle, combined with the construction status of ZJ2−1 and ZJ2−2 wells in Zhujidong Mine, the differences in fracturing effects of each section and level were analyzed from the perspectives of fracturing construction scale, fracturing construction curve, and pressure drop data, and compared and verified with microseismic monitoring results; Analyze the impact of drilling and fracturing effects on gas and water production efficiency, as well as the reasons for production shutdown, reveal the interaction mechanism between the entire cycle of surface horizontal well drilling, fracturing, and drainage engineering, and propose key issues and suggestions for gas control in surface horizontal wells in unmined coal mines. The results showed that the fracture opening effect of the coal seam in ZJ2−2 well was better than that of the top and bottom plate fracturing in ZJ2−1 well and ZJ2−1 well, while the microseismic results showed that the top and bottom plate fracturing had better fracture opening effect than the coal seam fracturing. This is because the fracturing effect is not only good, but also requires uniform crack opening and high crack persistence. The drilling effect is reflected in two aspects: drilling trajectory and wellbore stability. Drilling trajectory not only directly affects wellbore stability, but also affects fracturing effect. Fracturing construction will reduce wellbore stability, and wellbore stability is the foundation for ensuring the smooth progress of drainage projects. The stability of the wellbore cannot be ignored due to factors such as drilling layer, fracturing construction, reservoir rock layers, and long-term immersion. Good fracturing effect is only a necessary condition for good drainage effect, and the quality of drainage effect is largely influenced by the stability of the wellbore and the refinement of drainage system. The production stages of both wells can be divided into five stages: backflow, upward production, stable production, shutdown, and re production of gas. The backflow rate of ZJ2−1 well is relatively high and greater than 1, indicating the invasion of adjacent water sources, resulting in poor gas production of ZJ2−1 well with better fracturing effect. Finally, the key issues in the gas control process of surface horizontal wells in unmined areas of coal mines were summarized from the perspectives of optimal selection of surface horizontal well gas control technology, precise control of drilling trajectory, stability control of wellbore, optimization of drainage system, and detection of water storage environment. Corresponding development suggestions were provided in order to provide ideas for gas control of surface horizontal wells in unmined areas of coal mines.
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spelling doaj-art-ece966d5eb4e43bb850368ee6ade499c2025-08-20T03:11:29ZzhoEditorial Department of Coal Science and TechnologyMeitan kexue jishu0253-23362025-03-0153335636910.12438/cst.2024-11362024-1136Interaction mechanism and development suggestions for the full cycle construction effect of surface horizontal wells in unmined coal minesZhainan ZHANG0Ke YANG1Xinzhu HUA2Chunhui YE3Min YE4Wenjie LIU5Xiaolou CHI6Xin LYU7State Key Laboratory of Safe Mining of Deep Coal and Environmental Protection, Anhui University of Science and Technology, Huainan 232001, ChinaState Key Laboratory of Safe Mining of Deep Coal and Environmental Protection, Anhui University of Science and Technology, Huainan 232001, ChinaState Key Laboratory of Safe Mining of Deep Coal and Environmental Protection, Anhui University of Science and Technology, Huainan 232001, ChinaHuainan Mining (Group) Co., Ltd., Huainan 232001, ChinaHuainan Mining (Group) Co., Ltd., Huainan 232001, ChinaState Key Laboratory of Safe Mining of Deep Coal and Environmental Protection, Anhui University of Science and Technology, Huainan 232001, ChinaState Key Laboratory of Safe Mining of Deep Coal and Environmental Protection, Anhui University of Science and Technology, Huainan 232001, ChinaState Key Laboratory of Safe Mining of Deep Coal and Environmental Protection, Anhui University of Science and Technology, Huainan 232001, ChinaTo explore the differences in fracturing effects of different levels of ground level wells in unmined coal mines, and to reveal the interaction mechanism of construction effects in various stages of gas control throughout the entire cycle, combined with the construction status of ZJ2−1 and ZJ2−2 wells in Zhujidong Mine, the differences in fracturing effects of each section and level were analyzed from the perspectives of fracturing construction scale, fracturing construction curve, and pressure drop data, and compared and verified with microseismic monitoring results; Analyze the impact of drilling and fracturing effects on gas and water production efficiency, as well as the reasons for production shutdown, reveal the interaction mechanism between the entire cycle of surface horizontal well drilling, fracturing, and drainage engineering, and propose key issues and suggestions for gas control in surface horizontal wells in unmined coal mines. The results showed that the fracture opening effect of the coal seam in ZJ2−2 well was better than that of the top and bottom plate fracturing in ZJ2−1 well and ZJ2−1 well, while the microseismic results showed that the top and bottom plate fracturing had better fracture opening effect than the coal seam fracturing. This is because the fracturing effect is not only good, but also requires uniform crack opening and high crack persistence. The drilling effect is reflected in two aspects: drilling trajectory and wellbore stability. Drilling trajectory not only directly affects wellbore stability, but also affects fracturing effect. Fracturing construction will reduce wellbore stability, and wellbore stability is the foundation for ensuring the smooth progress of drainage projects. The stability of the wellbore cannot be ignored due to factors such as drilling layer, fracturing construction, reservoir rock layers, and long-term immersion. Good fracturing effect is only a necessary condition for good drainage effect, and the quality of drainage effect is largely influenced by the stability of the wellbore and the refinement of drainage system. The production stages of both wells can be divided into five stages: backflow, upward production, stable production, shutdown, and re production of gas. The backflow rate of ZJ2−1 well is relatively high and greater than 1, indicating the invasion of adjacent water sources, resulting in poor gas production of ZJ2−1 well with better fracturing effect. Finally, the key issues in the gas control process of surface horizontal wells in unmined areas of coal mines were summarized from the perspectives of optimal selection of surface horizontal well gas control technology, precise control of drilling trajectory, stability control of wellbore, optimization of drainage system, and detection of water storage environment. Corresponding development suggestions were provided in order to provide ideas for gas control of surface horizontal wells in unmined areas of coal mines.http://www.mtkxjs.com.cn/article/doi/10.12438/cst.2024-1136unmined areas of coal minesground level welldrilling trajectorysegmented fracturing effectgas and water productioninteraction mechanism
spellingShingle Zhainan ZHANG
Ke YANG
Xinzhu HUA
Chunhui YE
Min YE
Wenjie LIU
Xiaolou CHI
Xin LYU
Interaction mechanism and development suggestions for the full cycle construction effect of surface horizontal wells in unmined coal mines
Meitan kexue jishu
unmined areas of coal mines
ground level well
drilling trajectory
segmented fracturing effect
gas and water production
interaction mechanism
title Interaction mechanism and development suggestions for the full cycle construction effect of surface horizontal wells in unmined coal mines
title_full Interaction mechanism and development suggestions for the full cycle construction effect of surface horizontal wells in unmined coal mines
title_fullStr Interaction mechanism and development suggestions for the full cycle construction effect of surface horizontal wells in unmined coal mines
title_full_unstemmed Interaction mechanism and development suggestions for the full cycle construction effect of surface horizontal wells in unmined coal mines
title_short Interaction mechanism and development suggestions for the full cycle construction effect of surface horizontal wells in unmined coal mines
title_sort interaction mechanism and development suggestions for the full cycle construction effect of surface horizontal wells in unmined coal mines
topic unmined areas of coal mines
ground level well
drilling trajectory
segmented fracturing effect
gas and water production
interaction mechanism
url http://www.mtkxjs.com.cn/article/doi/10.12438/cst.2024-1136
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