MWD/Passive Magnetic Ranging makes use of the sensor data from the customers’ chosen MWD service provider to collect all the information that is needed to calculate the distance and direction between wellbores. When drilling in the vicinity of a cased wellbore, drillpipe or fish, the Earth’s magnetic field is disturbed as the offset casing or fish interferes with the field and presents a magnetic field of its own.
This disturbance, which can be thought of as “hot” MWD surveys, can be measured by any industry standard MWD system, and the measurements used to calculate the distance and direction between the drilling well and the nearby casing, drillpipe or fish. MWD/Passive ranging can be performed on short notice, typically without the need for additional equipment or personnel on location. On most jobs, all analysis can be performed remotely, and the ranging data and wellplan communicated via the remote operations center to the client’s office and drill site.