Design and field-scale demonstration of the buoyant-kill process for restoring integrity of wells with sustained casing pressure
Sustained Casing Pressure (SCP) is the persistent casinghead pressure resulting from the well’s annular integrity loss and migration of gas above the leaking cement sheath. Downhole—intervention methods for SCP removal employ workover rigs to access and plug off the leaking annulus at depth from wit...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2023-11-01
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| Series: | Frontiers in Energy Research |
| Subjects: | |
| Online Access: | https://www.frontiersin.org/articles/10.3389/fenrg.2023.1309207/full |
| _version_ | 1827632532143734784 |
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| author | Efecan Demirci Andrew Wojtanowicz |
| author_facet | Efecan Demirci Andrew Wojtanowicz |
| author_sort | Efecan Demirci |
| collection | DOAJ |
| description | Sustained Casing Pressure (SCP) is the persistent casinghead pressure resulting from the well’s annular integrity loss and migration of gas above the leaking cement sheath. Downhole—intervention methods for SCP removal employ workover rigs to access and plug off the leaking annulus at depth from within the well. The inexpensive rig-less method of Buoyant Kill involves surface injection of immiscible heavy fluid at the casinghead into the well’s annulus to replace the annular fluid column above the gas-leaking cement and stop gas migration. Laboratory and pilot-size testing have shown feasibility of the method. Presented here, is a field-scale demonstration experiment conducted in a pressurized 2750-foot well with water displaced by an immiscible brominated organic fluid over 20-h long operation. Discussed is experimental design supported by fluid selection study, benchtop and pilot tests, and fluid transport model. Also analyzed is the process performance and operational problems. The results confirm feasibility of the Buoyant Kill technique for SCP removal. The overall change of the wellhead and downhole pressures follows the expected patterns indicating partial removal of the simulated SCP. The removal is incomplete due to pumping pressure pulses and wellhead pressure variations resulting in some emulsification of the two fluids and partial loss of the injection fluid into the overflow. The results show that wellhead pressure control and injection pump operation are critical for successful SCP removal using the Buoyant Kill technique. |
| first_indexed | 2024-03-09T14:45:54Z |
| format | Article |
| id | doaj.art-e67037a7c32e425294f16427632e0ebf |
| institution | Directory Open Access Journal |
| issn | 2296-598X |
| language | English |
| last_indexed | 2024-03-09T14:45:54Z |
| publishDate | 2023-11-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Energy Research |
| spelling | doaj.art-e67037a7c32e425294f16427632e0ebf2023-11-27T06:55:56ZengFrontiers Media S.A.Frontiers in Energy Research2296-598X2023-11-011110.3389/fenrg.2023.13092071309207Design and field-scale demonstration of the buoyant-kill process for restoring integrity of wells with sustained casing pressureEfecan DemirciAndrew WojtanowiczSustained Casing Pressure (SCP) is the persistent casinghead pressure resulting from the well’s annular integrity loss and migration of gas above the leaking cement sheath. Downhole—intervention methods for SCP removal employ workover rigs to access and plug off the leaking annulus at depth from within the well. The inexpensive rig-less method of Buoyant Kill involves surface injection of immiscible heavy fluid at the casinghead into the well’s annulus to replace the annular fluid column above the gas-leaking cement and stop gas migration. Laboratory and pilot-size testing have shown feasibility of the method. Presented here, is a field-scale demonstration experiment conducted in a pressurized 2750-foot well with water displaced by an immiscible brominated organic fluid over 20-h long operation. Discussed is experimental design supported by fluid selection study, benchtop and pilot tests, and fluid transport model. Also analyzed is the process performance and operational problems. The results confirm feasibility of the Buoyant Kill technique for SCP removal. The overall change of the wellhead and downhole pressures follows the expected patterns indicating partial removal of the simulated SCP. The removal is incomplete due to pumping pressure pulses and wellhead pressure variations resulting in some emulsification of the two fluids and partial loss of the injection fluid into the overflow. The results show that wellhead pressure control and injection pump operation are critical for successful SCP removal using the Buoyant Kill technique.https://www.frontiersin.org/articles/10.3389/fenrg.2023.1309207/fullwell integritysustained casing pressureSCPwell cement failurewell completion efficiency |
| spellingShingle | Efecan Demirci Andrew Wojtanowicz Design and field-scale demonstration of the buoyant-kill process for restoring integrity of wells with sustained casing pressure Frontiers in Energy Research well integrity sustained casing pressure SCP well cement failure well completion efficiency |
| title | Design and field-scale demonstration of the buoyant-kill process for restoring integrity of wells with sustained casing pressure |
| title_full | Design and field-scale demonstration of the buoyant-kill process for restoring integrity of wells with sustained casing pressure |
| title_fullStr | Design and field-scale demonstration of the buoyant-kill process for restoring integrity of wells with sustained casing pressure |
| title_full_unstemmed | Design and field-scale demonstration of the buoyant-kill process for restoring integrity of wells with sustained casing pressure |
| title_short | Design and field-scale demonstration of the buoyant-kill process for restoring integrity of wells with sustained casing pressure |
| title_sort | design and field scale demonstration of the buoyant kill process for restoring integrity of wells with sustained casing pressure |
| topic | well integrity sustained casing pressure SCP well cement failure well completion efficiency |
| url | https://www.frontiersin.org/articles/10.3389/fenrg.2023.1309207/full |
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