Shell Oil Comapny

Robin Adrianus Hartmann

Harold J Vinegar

Christopher Kelvin Harris

Christopher Arnold Pratt

Randolph Rogers Wagner

Gordon Bruce Lepper

Elvira H Mulder

A method for forming one or more openings in a hydrocarbon containing formation is described. The method may include forming or providing a first opening in the formation. A plurality of magnets may be provided into the first opening. The plurality of magnets may be positioned along a portion of the first opening. The plurality of magnets may produce a series of magnetic fields along the portion of the first opening. A second opening in the formation may be formed using magnetic tracking of the series of magnetic fields. The second opening may be spaced a desired distance from the first opening. Alternate embodiments include use of an energized conduit to create a magnetic field. Such energized conduit can be used alone or with the plurality of magnets.

Forming openings in a hydrocarbon containing formation using magnetic tracking

A method of qualifying a survey of a borehole formed in an earth formation is provided. The method includes the steps of a) selecting a sensor for measuring an earth field parameter and a borehole position parameter in said borehole, b) determining theoretical measurement uncertainties of said parameters when measured with the sensor, c) operating said sensor so as to measure the position parameter and the earth field parameter at a selected position in the borehole, d) determining the difference between the measured earth field parameter and a known magnitude of said earth field parameter at said position, and determining the ratio of said difference and the theoretical measurement uncertainty of the earth field parameter, and e) determining the uncertainty of the measured position parameter from the product of said ratio and the theoretical measurement uncertainty of the position parameter.

Method of qualifying a borehole survey

In a method for drilling adjacent to a cased known first borehole a second borehole in a predetermined direction the following steps are carried out for a number of along hole depths d.sub.i :

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Rijswijk, Netherlands

Robin Adrianus Hartmann