Patent ID: 8427162
Filing Date: 2013-04-23
Classification: E21B

Abstract:
1. A method for estimating a position of a second borehole relative to an existing first borehole, the method comprising: conveying a position sensing device with a drilling tool in the second borehole, the position sensing device being configured to sense the first borehole; transmitting a first signal from the position sensing device towards the first borehole, the first signal comprising a type of energy; receiving a second signal with the position sensing device in response to the first signal interacting with the first borehole or material at the first borehole, the second signal comprising the same type of energy as the first signal; and estimating the position of the second borehole relative to the first borehole using the position sensing device; wherein the second signal comprises information indicative of the position of the second borehole relative to the first borehole.