Stability Characteristics of Horizontal Wells in the Exploitation of Hydrate-Bearing Clayey-Silt Sediments
The mechanical properties of hydrate-bearing strata in clayey-silt sediments are significantly different from those of either conventional reservoirs or hydrate-bearing sandy sediments, which poses great challenges for wellbore stability analyses. The stability characteristics of a deviated borehole...
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MDPI AG
2022-12-01
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| Series: | Journal of Marine Science and Engineering |
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| Online Access: | https://www.mdpi.com/2077-1312/10/12/1935 |
| _version_ | 1827638246713065472 |
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| author | Xiaofeng Sun Qiaobo Hu Yanlong Li Mingtao Chen Yajuan Zhang |
| author_facet | Xiaofeng Sun Qiaobo Hu Yanlong Li Mingtao Chen Yajuan Zhang |
| author_sort | Xiaofeng Sun |
| collection | DOAJ |
| description | The mechanical properties of hydrate-bearing strata in clayey-silt sediments are significantly different from those of either conventional reservoirs or hydrate-bearing sandy sediments, which poses great challenges for wellbore stability analyses. The stability characteristics of a deviated borehole during drilling in hydrate-bearing clayey-silt sediments (HBS-CS) remain to be studied. In this paper, an analysis of the wellbore stability characteristics of a deviated borehole using the Mohr–Coulomb (M-C) criterion and Drucker–Prager (D-P) criterion was carried out based on the elastic stress distribution model of the surrounding strata of the wellbore and the triaxial shear tests of the HBS-CS. The results imply that the collapse pressure and safety density window are symmetrically distributed with deviation angle and azimuth. Considering the effect of hydrate decomposition, the collapse pressure gradient could become higher and the instability risks would be amplified. Considering the combined effects of collapse, fracture pressure gradient, and the safety density window, it is suggested that the borehole be arranged along an azimuth of 60–120°, which could greatly reduce the risk in a drilling operation. |
| first_indexed | 2024-03-09T16:13:48Z |
| format | Article |
| id | doaj.art-5280fac26a4a44648c569753bb94e372 |
| institution | Directory Open Access Journal |
| issn | 2077-1312 |
| language | English |
| last_indexed | 2024-03-09T16:13:48Z |
| publishDate | 2022-12-01 |
| publisher | MDPI AG |
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| series | Journal of Marine Science and Engineering |
| spelling | doaj.art-5280fac26a4a44648c569753bb94e3722023-11-24T15:56:51ZengMDPI AGJournal of Marine Science and Engineering2077-13122022-12-011012193510.3390/jmse10121935Stability Characteristics of Horizontal Wells in the Exploitation of Hydrate-Bearing Clayey-Silt SedimentsXiaofeng Sun0Qiaobo Hu1Yanlong Li2Mingtao Chen3Yajuan Zhang4Sanya Offshore Oil and Gas Research Institute, Northeast Petroleum University, Sanya 572025, ChinaSanya Offshore Oil and Gas Research Institute, Northeast Petroleum University, Sanya 572025, ChinaKey Laboratory of Gas Hydrate, Ministry of Natural Resources, Qingdao Institute of Marine Geology, Qingdao 266237, ChinaKey Laboratory of Gas Hydrate, Ministry of Natural Resources, Qingdao Institute of Marine Geology, Qingdao 266237, ChinaKey Laboratory of Gas Hydrate, Ministry of Natural Resources, Qingdao Institute of Marine Geology, Qingdao 266237, ChinaThe mechanical properties of hydrate-bearing strata in clayey-silt sediments are significantly different from those of either conventional reservoirs or hydrate-bearing sandy sediments, which poses great challenges for wellbore stability analyses. The stability characteristics of a deviated borehole during drilling in hydrate-bearing clayey-silt sediments (HBS-CS) remain to be studied. In this paper, an analysis of the wellbore stability characteristics of a deviated borehole using the Mohr–Coulomb (M-C) criterion and Drucker–Prager (D-P) criterion was carried out based on the elastic stress distribution model of the surrounding strata of the wellbore and the triaxial shear tests of the HBS-CS. The results imply that the collapse pressure and safety density window are symmetrically distributed with deviation angle and azimuth. Considering the effect of hydrate decomposition, the collapse pressure gradient could become higher and the instability risks would be amplified. Considering the combined effects of collapse, fracture pressure gradient, and the safety density window, it is suggested that the borehole be arranged along an azimuth of 60–120°, which could greatly reduce the risk in a drilling operation.https://www.mdpi.com/2077-1312/10/12/1935natural gas hydrateclayey-siltdeviated boreholestability characteristicshydrate saturationcollapse pressure |
| spellingShingle | Xiaofeng Sun Qiaobo Hu Yanlong Li Mingtao Chen Yajuan Zhang Stability Characteristics of Horizontal Wells in the Exploitation of Hydrate-Bearing Clayey-Silt Sediments Journal of Marine Science and Engineering natural gas hydrate clayey-silt deviated borehole stability characteristics hydrate saturation collapse pressure |
| title | Stability Characteristics of Horizontal Wells in the Exploitation of Hydrate-Bearing Clayey-Silt Sediments |
| title_full | Stability Characteristics of Horizontal Wells in the Exploitation of Hydrate-Bearing Clayey-Silt Sediments |
| title_fullStr | Stability Characteristics of Horizontal Wells in the Exploitation of Hydrate-Bearing Clayey-Silt Sediments |
| title_full_unstemmed | Stability Characteristics of Horizontal Wells in the Exploitation of Hydrate-Bearing Clayey-Silt Sediments |
| title_short | Stability Characteristics of Horizontal Wells in the Exploitation of Hydrate-Bearing Clayey-Silt Sediments |
| title_sort | stability characteristics of horizontal wells in the exploitation of hydrate bearing clayey silt sediments |
| topic | natural gas hydrate clayey-silt deviated borehole stability characteristics hydrate saturation collapse pressure |
| url | https://www.mdpi.com/2077-1312/10/12/1935 |
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