An induction device and method for introducing an inductor loop into a rock formation to heating an oil reservoir in the rock formation to extract oil extraction, wherein a first inductor bore is chilled for introducing a first inductor arm, a second inductor bore is drilled for introducing a second inductor arm, at least one intersecting bore is drilled to create a first area of intersection with the first inductor bore and a second area of intersection with the second inductor bore, the first inductor arm is introduced into the first inductor bore and the second inductor arm is introduced into the second inductor bore, and at least one connecting arm is introduced into the intersecting bore for electrically conductive connection to the two inductor arms in the two areas of intersection so as to form the inductor loop.