发明名称 |
FINE CONTROL OF CASING PRESSURE |
摘要 |
Back pressure control devices used to control fluid pressure in a wellbore require various utilities for operation, such as an air supply. Apparatus disclosed herein provide for the continued operation of one or more back pressure control devices when supply of utilities for operation of the back pressure control devices are intentionally or unintentionally interrupted. |
申请公布号 |
CA2859372(A1) |
申请公布日期 |
2013.06.20 |
申请号 |
CA20122859372 |
申请日期 |
2012.12.13 |
申请人 |
M-I L.L.C. |
发明人 |
SUTER, ROGER;MOLLEY, DAVID |
分类号 |
E21B43/12;E21B47/06 |
主分类号 |
E21B43/12 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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