Abstract:
An apparatus and method for estimating a resistivity property of an earth formation involving electric current induced in an earth formation. The method may include reducing an error in a voltage received by a receiver coil due to excitation of a transmitter coil due to temperature effects. The voltage may include amplitude and/or phase errors. The method may modify the measured voltage by multiplying/dividing the voltage by a reduction factor. The reduction factor may be determined using polynomic curve fitting. The apparatus may be configured to perform the method. The apparatus may include at least one transmitter coil, at least one receiver coil, and at least one processes configured to perform the error reduction.
Abstract:
A multipole antenna for conducting logging-while-drilling (LWD), includes a wire for one of producing and receiving an electromagnetic field, the wire having at least one winding for providing a magnetic moment in a first portion of the antenna that is opposite to the magnetic moment of a second portion of the antenna. A method for constructing the multipole antenna is provided. A LWD tool making use of the antenna is also provided.
Abstract:
The disclosure provides a resistivity tool for use in a wellbore, wherein at least two antennas are located at the same or substantially the same location of the tool. Each antenna may be configured to operate as a transmitter or receiver.
Abstract:
A combination of a shallow-reading and a deep-reading, azimuthally sensitive, multiple propagation devices is used for providing depth images the earth formation with different depth of investigation. It is emphasized that this abstract is provided to comply with the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.
Abstract:
An apparatus for measuring one or more earth formation properties during applications including formation evaluation and geosteering applications is provided. The apparatus includes: an elongated body; at least one recessed portion on a periphery of the elongated body; an electrically conductive coil forming a closed loop, at least a portion of the coil extending through the at least one recessed portion; and a u-shaped magnetically permeable and non-conductive material disposed between the coil and the at least one recessed portion, the u-shaped material partially surrounding the coil in the at least one recessed portion. A system for measuring one or more properties of an earth formation is also provided.