2.2.2. Industrial reflection seismology

During the last decades the international oil and gas industry has invested billions of dollars in advancing the science and technology of reflection seismology. Today, very advanced seismic recording instrumentation, processing technologies and very advanced seismic imaging algorithms generate astonishingly well-resolved and accurate images at a large depth range (0.1 - 10 km). Using state-of-the-art 3-D seismic imaging of today, it is possible to obtain a 3-D data cube representing the Earth below the plane of seismic measurements. 2-D depth slices through such data cubes are of such quality that geologists can readily interpret them in terms of depositional history and structural evolution. Time series of 3-D seismic cubes (“4-D time lapse seismics”) can even provide information on the temporal evolution of a geological structure, e.g. as a result of hydrocarbon extraction or of CO2 injection.

On the other hand, a priori geological information is a requisite for constraining geophysical operations. A major task of sedimentary geologists in TOPO-EUROPE will be to formulate depositional models on the base of available borehole and seismic data that can be iteratively tested by reflection-seismic data sets. Notwithstanding the success of the seismic method, passive potential-field methods, such as gravity surveying and geomagnetic techniques, are valuable tools for prospecting deep sedimentary basins in which it is difficult to obtain high-quality reflection-seismic data. The reflection-seismic and potential-field methods complement each other. The seismic method delineates horizontal and vertical density and velocity contrasts, while gravity and geomagnetic data image only vertical density and magnetization discontinuities, respectively. Moreover, the seismic and potential-field methods differ in the scale of their resolution. Potential field methods can provide first approximation information on the distribution of igneous rocks, the depth to crystalline basement, the thickness of sedimentary strata, and potentially the location of deep-seated structures.