Gravity/magnetics: A new 3-D survey dimension

In parallel with advances in 3-D seismic technology, there have also been a number of giant steps forward in non-seismic 3-D geophysical applications. Non-seismic methods, when recorded in conjunction with a 3-D seismic program, offer the benefit of an independently measured geophysical property which can be effectively used to verify, refine and constrain a 3-D velocity model and/or seismic interpretation. This is a dramatic change from more classical gravity- and magnetic-data applications, such as mapping of magnetic or high-density basement, basin delineation, sedimentary sequence thicknesses and volcanic rocks. This paper reviews these advances in 3-D gravity and magnetic survey methods.