Physical experiment on the feasibility of variable-gradient drilling method based on downhole separator
The special temperature-pressure environment and narrow safety density window of the deepwater formation pose a great challenge to wellbore pressure control during drilling. The downhole variable-gradient drilling method is an effective idea to solve this challenge. However, previous studies mainly...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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Elsevier
2022-11-01
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| Series: | Energy Reports |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S2352484721015092 |
| _version_ | 1797902110039212032 |
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| author | Hongwei Yang Jun Li Hui Zhang Gonghui Liu Geng Zhang Boyun Guo |
| author_facet | Hongwei Yang Jun Li Hui Zhang Gonghui Liu Geng Zhang Boyun Guo |
| author_sort | Hongwei Yang |
| collection | DOAJ |
| description | The special temperature-pressure environment and narrow safety density window of the deepwater formation pose a great challenge to wellbore pressure control during drilling. The downhole variable-gradient drilling method is an effective idea to solve this challenge. However, previous studies mainly focused on the theoretical adaptability analysis of this method, while the experimental feasibility verification has not yet been reported. In this paper, based on the segmental control principle of wellbore fluid density, we set up an indoor physical experiment system to investigate the feasibility of variable-gradient drilling method based on downhole cyclone separator. Using this experimental system, we investigated the effect of drilling fluid physical parameters, hollow glass microsphere (HGMS) performance parameters and engineering parameters on the separator separation efficiency, wellbore pressure gradient and HGMS slip rate. The experimental results revealed that the separator could separate the HGMSs into the annulus from the fluid mixture in the drill pipe. The separation efficiency increased with the increase in the HGMS diameter, HGMS concentration and flow rate, while decreased with the increase in the HGMS density and fluid viscosity. The HGMS density and HGMS concentration were the key factors affecting the annulus pressure gradient value, and the separator separation efficiency was the main factor determining the difference of the annulus pressure gradient. The HGMS slip rate was highly sensitive to its diameter and fluid viscosity, and a combination of optimal HGMS diameter and fluid viscosity could avoid the drilling risk caused by the HGMS slippage. Therefore, the variable-gradient drilling method based on downhole separator is feasible, which is able to create two or more pressure gradients in the annulus. This study could provide guidance for the optimization of key parameters and the development of equipment related to the variable-gradient drilling. |
| first_indexed | 2024-04-10T09:12:36Z |
| format | Article |
| id | doaj.art-e07148fe2197467c89983b27fbbb30d0 |
| institution | Directory Open Access Journal |
| issn | 2352-4847 |
| language | English |
| last_indexed | 2024-04-10T09:12:36Z |
| publishDate | 2022-11-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Energy Reports |
| spelling | doaj.art-e07148fe2197467c89983b27fbbb30d02023-02-21T05:10:02ZengElsevierEnergy Reports2352-48472022-11-01815911601Physical experiment on the feasibility of variable-gradient drilling method based on downhole separatorHongwei Yang0Jun Li1Hui Zhang2Gonghui Liu3Geng Zhang4Boyun Guo5China University of Petroleum-Beijing, Beijing 102249, ChinaChina University of Petroleum-Beijing, Beijing 102249, China; China University of Petroleum-Beijing at Karamay, Karamay 834000, China; Corresponding author at: China University of Petroleum-Beijing, Beijing 102249, China.China University of Petroleum-Beijing, Beijing 102249, ChinaChina University of Petroleum-Beijing, Beijing 102249, ChinaChina University of Petroleum-Beijing, Beijing 102249, ChinaUniversity of Louisiana at Lafayette, Lafayette, LA, 70504, USAThe special temperature-pressure environment and narrow safety density window of the deepwater formation pose a great challenge to wellbore pressure control during drilling. The downhole variable-gradient drilling method is an effective idea to solve this challenge. However, previous studies mainly focused on the theoretical adaptability analysis of this method, while the experimental feasibility verification has not yet been reported. In this paper, based on the segmental control principle of wellbore fluid density, we set up an indoor physical experiment system to investigate the feasibility of variable-gradient drilling method based on downhole cyclone separator. Using this experimental system, we investigated the effect of drilling fluid physical parameters, hollow glass microsphere (HGMS) performance parameters and engineering parameters on the separator separation efficiency, wellbore pressure gradient and HGMS slip rate. The experimental results revealed that the separator could separate the HGMSs into the annulus from the fluid mixture in the drill pipe. The separation efficiency increased with the increase in the HGMS diameter, HGMS concentration and flow rate, while decreased with the increase in the HGMS density and fluid viscosity. The HGMS density and HGMS concentration were the key factors affecting the annulus pressure gradient value, and the separator separation efficiency was the main factor determining the difference of the annulus pressure gradient. The HGMS slip rate was highly sensitive to its diameter and fluid viscosity, and a combination of optimal HGMS diameter and fluid viscosity could avoid the drilling risk caused by the HGMS slippage. Therefore, the variable-gradient drilling method based on downhole separator is feasible, which is able to create two or more pressure gradients in the annulus. This study could provide guidance for the optimization of key parameters and the development of equipment related to the variable-gradient drilling.http://www.sciencedirect.com/science/article/pii/S2352484721015092Deepwater formationVariable-gradient drillingWellbore pressure gradientCyclone separatorHollow glass microsphere |
| spellingShingle | Hongwei Yang Jun Li Hui Zhang Gonghui Liu Geng Zhang Boyun Guo Physical experiment on the feasibility of variable-gradient drilling method based on downhole separator Energy Reports Deepwater formation Variable-gradient drilling Wellbore pressure gradient Cyclone separator Hollow glass microsphere |
| title | Physical experiment on the feasibility of variable-gradient drilling method based on downhole separator |
| title_full | Physical experiment on the feasibility of variable-gradient drilling method based on downhole separator |
| title_fullStr | Physical experiment on the feasibility of variable-gradient drilling method based on downhole separator |
| title_full_unstemmed | Physical experiment on the feasibility of variable-gradient drilling method based on downhole separator |
| title_short | Physical experiment on the feasibility of variable-gradient drilling method based on downhole separator |
| title_sort | physical experiment on the feasibility of variable gradient drilling method based on downhole separator |
| topic | Deepwater formation Variable-gradient drilling Wellbore pressure gradient Cyclone separator Hollow glass microsphere |
| url | http://www.sciencedirect.com/science/article/pii/S2352484721015092 |
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