Patent attributes
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 transmitting power and communicating signals to the remote sensing unit and for receiving communication signals from the remote sensor, a casing joint having nonconductive “windows” for allowing an internally located antenna to communicate with the remote sensing unit for those embodiments in which a wireline tool is being used to communicate with 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 a standalone sensor that 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 to determine certain subsurface formation characteristics such as pressure or temperature, and transmitting corresponding data values to a wellbore tool. Some embodiments of the remote sensing unit include a battery within its power supply. Other embodiments include a capacitor for storing charge. The embodiments that include the capacitor receive RF power that is converted to a DC signal for storing charge on the capacitor. The charged capacitor then acts as a power source to provide power to the internal circuitry of the remote sensing unit. When the charge is depleted to a specified point, the remote sensing unit stops transmitting to prompt the wellbore tool to transmit additional RF power to recharge the capacitor. This particular embodiment allows the remote sensing unit to be operable well after any charge of a battery would have been depleted rendering the remote sensing unit inoperable. An inventive method therefore includes providing RF power 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 that are then transmitted to the surface where operational decisions for the well may be made. In one embodiment of the invention, the subsurface formation data values are transmitted to a central location for analysis.
