| 摘要 |
A method of constructing a well comprising a borehole drilled through underground formations, comprises: positioning at least one device on the outside of the tubular string (e.g. a drill string or casing string), the device being operable to move between first and second configurations; positioning a tubular string in the borehole with the device positioned in the annular space between the tubular string and the borehole wall in its first configuration so as to interact with the tubular string and the borehole while allowing borehole fluid to flow along the annular space and around the device; and operating the device so as to move it from its first configuration to expand into its second configuration in which it substantially fills at least part of the annular space so as to inhibit flow of fluids along the borehole in the space. Apparatus comprises: a string of tubular members; at least one device positioned on the outside of the string, the device being operable to expand between: (i) a first configuration in which, when the tubular string is positioned in the borehole with the device located in the annular space between the tubular string and the borehole wall, interacts with the tubular string and the borehole while allowing borehole fluid to flow along the annular space and around the device; and (ii) a second configuration in which it substantially fills at least part of the annular space so as to prevent flow of fluids along the borehole in the space.
|
