Active Magnetic Ranging While Drilling: Performance Test

Abstract

During the well intercept drilling enterprise, several wireline logging operations are being run. The drill pipe is pulled out of the well and a wireline tool is run in. From the wireline tool a very low frequency alternating current is emitted into the formation to reach the target well casing. Then the electric current runs down the casing and back into the bottom of the relief well. This current set up a variable magnetic field that is measured by magnetometers in the relief well. Thus, the direction towards the target well can be determined. The drilling direction is accordingly adjusted, and drilling is continued. Typically, a number of 10 – 25 similar wireline navigation runs are needed before the target well is intercepted. The operation with pulling drill pipe out of the well, running the wireline operation and finally running the drill string back into the well typically cost several days drilling time. A prototype of a tool for Active Magnetic Ranging While Drilling has been developed. The scope of using this tool is to perform similar logging operations as currently being performed with the wireline operations, with an integrated tool systems on the relief well drill pipe. Thus, all the tripping operations are avoided and the time to drill the relief well is significantly reduced. This tool is described in detail in the following. Focus will be given to performance tests conducted in the laboratory and in a research well in Norway. A drill pipe is placed in a target well. Then a drill pipe including the measurement tool is run in a neighbour well and the direction and distance to the target well is measured. The set-up and results of this logging operation conducted on a drill pipe is described in detail.