Patent ID: 8055447

Claim:
A method for tracking migration of a target fluid media contained in a fluid reservoir within a formation layer at a given subsurface depth of at least five hundred feet relative to a terrain surface, the method comprising: from multiple positions on or below the terrain surface, transmitting immediately in the far field pulsed electromagnetic energy beam signals that combine to cover a target area of the formation layer containing the fluid reservoir; receiving reflections from the target area in response to the transmitted pulsed energy beam signals impinging thereon, the reflections being characteristic of particular media located within the target area being impinged upon by the transmitted far field pulsed electromagnetic energy beam signals; correlating the received reflections from said target area over a given time interval to determine relative changes in intensities of reflections over said target area; and determining relative movement of said target fluid media according to said determined relative changes in intensities of said reflections over said target area.