Methods and apparatus for subsurface geophysical exploration using joint inversion of steady-state and transient data

摘要

Methods and apparatus are provided for controlled source electromagnetic surveying. In particular, a time-varying electromagnetic signal is transmitted at a first location, and an electromagnetic signal responsive to the transmitted signal is received at a second location, wherein the received signal includes a transient response component and a steady-state component. The received signal is continuously recorded during a predetermined time interval, and data corresponding to the transient response component and the steady-state component are extracted from the received signal. The transient response data and the steady-state response data are jointly inverted to identify a subsurface feature, such as resistivity.