| 摘要 |
An apparatus and a method for controlling oilfield production to improve efficiency includes a remote sensing unit that is placed within a subsurface formation, an antenna structure for communicating with the remote sensing unit, a casing joint having nonconductive "windows" for allowing a internally located antenna to communicate with the remote sensing unit, and a system for obtaining subsurface formation data and for producing the formation data to a central location for subsequent analysis. The remote sensing unit is placed sufficiently far from the wellbore to reduce or eliminate effects that the wellbore might have on formation data samples taken by the remote sensing unit. The remote sensing unit is an active device with the capability of responding to control commands by determining certain subsurface formation characteristics such as pressure or temperature, and transmitting corresponding data values to a wellbore tool. The inventive system includes an antenna structure that is for delivering power and communication signals to the remote sensing unit. In one embodiment, the antenna structure is formed on an external surface of a wellbore casing. In another embodiment, the antenna structure is formed on a downhole tool such as a drilling collar or a cased hole wireline tool. For those embodiments in which the antenna structure is formed on a cased holed wireline tool, a casing joint is provided that includes nonconductive windows for allowing RF signals to be transmitted from within the casing to the remote sensing unit and from the remote sensing unit to the wireline tool. An inventive method therefore includes providing RF power through the inventive antenna system to the remote sensing unit to wake it up and to place it into an operational mode. The method further includes receiving modulated data values from the remote sensing unit through the antenna system that are then transmitted to the surface where operational decisions for the well may be made.
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