Patent ID: 8307915

Claim:
A method for drilling a pair of wells comprising: drilling and casing a first fishbone well in a subsurface formation, the first fishbone well having a first plurality of multilateral junctions for a first plurality of lateral wells such that the first plurality of lateral wells each has a liner; and drilling a second fishbone well having a second plurality of multilateral junctions for a second plurality of lateral wells using a bottom hole assembly having a drill bit, an electric current driving tool, and a magnetometer; and wherein drilling the second fishbone well includes (i) causing the electric current driving tool to provide an electrical current that travels through the subsurface formation to at least one of the first plurality of lateral wells and along the liner such that the current traveling along the liner creates a magnetic field, (ii) causing the magnetometer to measure the magnetic field, and (iii) magnetically ranging while drilling the second plurality of lateral wells at a controlled distance of separation above or below the first plurality of lateral wells using the magnetometer measurement.