A method of determining the rotational orientation of a downhole tool on a rotatable conduit, such as a collar on a drillstring in a borehole, without interrupting the rotation of the drillstring, includes establishing the initial rotational orientation of the downhole tool; creating a pressure change...http://www.google.es/patents/US5103919?utm_source=gb-gplus-sharePatente US5103919 - Method of determining the rotational orientation of a downhole tool
Method of determining the rotational orientation of a downhole tool
