Patent attributes
The invention provides a method of locating, in terrain containing oil sand deposits and also containing shale, clean oil sands deposits (i.e. those not containing significant shale) which are large enough for economic exploitation. The method includes flying a high sensitivity gravity gradiometer over the terrain and measuring at least one component, preferably the vertical component, of the local gravity gradient field at a number of points in a grid pattern on the terrain. The densities of sand and shale are normally approximately the same, making it difficult to distinguish them. However in an oil sands environment, there can be a sufficient difference in bulk density such that by using a very sensitive gravity gradiometer, or by otherwise reducing the noise signal using appropriate surveying methods, large clean oil sand deposits can be distinguished from other oil sand deposits not large enough for economic exploitation.
