Patent application number | Description | Published |
20110308794 | Real Time Determination of Casing Location and Distance with Tilted Antenna Measurement - Methods and apparatus for detecting nearby conductors such as pipes, well casing, etc., from within a borehole. A nearby casing string can be detected by transmitting an electromagnetic signal from a first antenna on a downhole logging tool and measuring a response signal with a second antenna. As the tool rotates, the transmitting and measuring are repeated to determine the azimuthal dependence of the response signal. The azimuthal dependence is analyzed to determine an diagonal component and a cross component. The amplitude of the diagonal component is indicative of distance to the conductive feature. Direction can be determined based on the diagonal component alone or in combination with the cross component. Sinusoidal curve fitting can be employed to improve accuracy of the distance and direction estimates. At least one of the antennas is preferably tilted. Measurement results are presented for parallel tilted and perpendicular tilted antennas. | 12-22-2011 |
20120001637 | CORRECTING FOR MAGNETIC INTERFERENCE IN AZIMUTHAL TOOL MEASUREMENTS - Methods and systems that compensate for magnetic interference in azimuthal tool measurements. At least some method embodiments include a downhole logging method that includes taking measurements as a function of orientation from inside a borehole. The measurements are associated with different azimuthal bins, and an azimuthal direction is determined for each azimuthal bin. Because the tool rotates at a constant rate, the relative number of measurements associated which the different bins can be used to measure the effective sizes of the different bins and to redetermine the effective angles of the bins in the presence of magnetic interference. The tool measurements may include, but are not limited to, formation resistivity, magnetic field, and formation density. | 01-05-2012 |
20140191879 | CASING DETECTION TOOLS AND METHODS - Methods and tools for detecting casing position downhole is presented. The method utilizes electromagnetic. (EM) tools with tilted antenna systems to detect casing position. Sometimes titled antenna designs also increase EM tools' sensitivity to formation parameters, which can lead to false signals for casing detection. In addition, it is very difficult to distinguish measured signals between a casing source and a formation source. The methods presented help to distinguish between the two sources more clearly. The methods and tools presented also help to minimize those environmental effects, as well as enhance the signals from a surrounding conductive casing. The methods herein provide ideas of EM tool's design to precisely determine casing position within a certain distance to casing position. | 07-10-2014 |