Single-borehole imaging using gravity gradiometer data

We present a feasibility study for interpretation of gravity gradient surveys in a single borehole using both an analytic and inverse-based approach. We analytically solve for distance and direction angles to a point source using the components of the gravity gradient tensor from a set of observations in a single borehole. We then generalize this approach to include the response due to a prismatic source. By inverting multiple sets of tensor components for 3D density contrast distributions, we show that as few as two independent gravity gradient components in a single borehole can be used to locate and image subsurface anomalous bodies. However, gradient measurements in a single borehole are insufficient to resolve multiple closelyspaced compact bodies.