Experimental investigation on fracture initiation and non-planar propagation of hydraulic fractures in coal seams
True tri-axial test system was deployed for fracturing simulation of coal outcrops to investigate the initiation and propagation of hydraulic fractures in vertical and directional wells. The influences of in-situ stress and cleats on non-planar propagation of hydraulic fractures in directional wells...
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| Format: | Article |
| Language: | English |
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KeAi Communications Co., Ltd.
2017-06-01
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| Series: | Petroleum Exploration and Development |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S187638041730054X |
| _version_ | 1831636165702189056 |
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| author | Peng TAN Yan JIN Bing HOU Ke HAN Yingcao ZHOU Shangzhi MENG |
| author_facet | Peng TAN Yan JIN Bing HOU Ke HAN Yingcao ZHOU Shangzhi MENG |
| author_sort | Peng TAN |
| collection | DOAJ |
| description | True tri-axial test system was deployed for fracturing simulation of coal outcrops to investigate the initiation and propagation of hydraulic fractures in vertical and directional wells. The influences of in-situ stress and cleats on non-planar propagation of hydraulic fractures in directional wells under different relative azimuths were analyzed. The test results show that the general propagation pattern of hydraulic fractures is jointly controlled by azimuth, cleats and in-situ stress. As the relative azimuth increases, the hydraulic fractures become more complicated in geometry and subject to increasing pumping pressure and propagation pressure. If the hydraulic fractures are initiated along a direction skewed with wellbore, the effect of cleats would alter the extension path and appear distortion of hydraulic fractures, inducing more complicated fracture geometry near the wellbore, with many fractures at the initiation point. Compared with vertical wells where I-shaped or X-shaped hydraulic fractures are formed, directional wells often have twisty propagation of dominant fractures near the wellbore and presence of multi-level fractures, which impede the further extension of hydraulic fractures in coal seams. Key words: coal seams, directional well, hydraulic fracturing, fracture propagation, fracture geometry, non-planar propagation |
| first_indexed | 2024-12-19T06:28:14Z |
| format | Article |
| id | doaj.art-c704cde47a364fe495ab54655aeb1cef |
| institution | Directory Open Access Journal |
| issn | 1876-3804 |
| language | English |
| last_indexed | 2024-12-19T06:28:14Z |
| publishDate | 2017-06-01 |
| publisher | KeAi Communications Co., Ltd. |
| record_format | Article |
| series | Petroleum Exploration and Development |
| spelling | doaj.art-c704cde47a364fe495ab54655aeb1cef2022-12-21T20:32:28ZengKeAi Communications Co., Ltd.Petroleum Exploration and Development1876-38042017-06-01443470476Experimental investigation on fracture initiation and non-planar propagation of hydraulic fractures in coal seamsPeng TAN0Yan JIN1Bing HOU2Ke HAN3Yingcao ZHOU4Shangzhi MENG5State Key Laboratory of Petroleum Resources and Engineering, China University of Petroleum, Beijing 102249, ChinaState Key Laboratory of Petroleum Resources and Engineering, China University of Petroleum, Beijing 102249, China; Corresponding authorState Key Laboratory of Petroleum Resources and Engineering, China University of Petroleum, Beijing 102249, ChinaState Key Laboratory of Petroleum Resources and Engineering, China University of Petroleum, Beijing 102249, ChinaCNPC Drilling Engineering Research Institute, Beijing 100195, ChinaChina United Coalbed Methane Co., Ltd, Beijing 100011, ChinaTrue tri-axial test system was deployed for fracturing simulation of coal outcrops to investigate the initiation and propagation of hydraulic fractures in vertical and directional wells. The influences of in-situ stress and cleats on non-planar propagation of hydraulic fractures in directional wells under different relative azimuths were analyzed. The test results show that the general propagation pattern of hydraulic fractures is jointly controlled by azimuth, cleats and in-situ stress. As the relative azimuth increases, the hydraulic fractures become more complicated in geometry and subject to increasing pumping pressure and propagation pressure. If the hydraulic fractures are initiated along a direction skewed with wellbore, the effect of cleats would alter the extension path and appear distortion of hydraulic fractures, inducing more complicated fracture geometry near the wellbore, with many fractures at the initiation point. Compared with vertical wells where I-shaped or X-shaped hydraulic fractures are formed, directional wells often have twisty propagation of dominant fractures near the wellbore and presence of multi-level fractures, which impede the further extension of hydraulic fractures in coal seams. Key words: coal seams, directional well, hydraulic fracturing, fracture propagation, fracture geometry, non-planar propagationhttp://www.sciencedirect.com/science/article/pii/S187638041730054X |
| spellingShingle | Peng TAN Yan JIN Bing HOU Ke HAN Yingcao ZHOU Shangzhi MENG Experimental investigation on fracture initiation and non-planar propagation of hydraulic fractures in coal seams Petroleum Exploration and Development |
| title | Experimental investigation on fracture initiation and non-planar propagation of hydraulic fractures in coal seams |
| title_full | Experimental investigation on fracture initiation and non-planar propagation of hydraulic fractures in coal seams |
| title_fullStr | Experimental investigation on fracture initiation and non-planar propagation of hydraulic fractures in coal seams |
| title_full_unstemmed | Experimental investigation on fracture initiation and non-planar propagation of hydraulic fractures in coal seams |
| title_short | Experimental investigation on fracture initiation and non-planar propagation of hydraulic fractures in coal seams |
| title_sort | experimental investigation on fracture initiation and non planar propagation of hydraulic fractures in coal seams |
| url | http://www.sciencedirect.com/science/article/pii/S187638041730054X |
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