Production • Processing • Handling
SEEPFINDER and GRAVEX technologies. SEEPFINDER is a computer controlled airborne optical spectrometer capable of detecting fluorescence from minute concentrations of hydrocarbons on the surface of water. Te ultra- violet components of sunlight cause the polycyclic aromatic compounds in crude oil to fluoresce, and the composite signature of these emissions in the visible spectrum is detected and mapped by SEEPFINDER. Mounted in a light aircraft, together with a high-resolution magnetometer and often a gravity measurement system, survey results are presented as contour and analysis maps, showing light (L), medium (M) and heavy (H) oil types and a composite map of all seepage signatures.
While SEEPFINDER data is
not directly calibrated in API units, an approximate assignment would give light >35°, mid 25° to 35°, and heavy below 25°. Te amplitudes of the analysis maps are adjusted to give approximately the same colour balance for each map, whereas the composite map shows the true relationship between the different regions and/or types of seepage. Seep and aeromagnetic data often correlate, as shown in the above example. Note the exact correspondences between the emergence points and the low susceptibility points in the magnetic data. Tey are excellent, and give additional confidence to the seep data. Over 350,000 kilometres of survey data has been
acquired by SEEPFINDER systems worldwide, for a client base of over 30 of the world’s major oil companies.
SEEPFINDER is not the ultimate exploration
tool; however, it is a valuable tool in the tool-box. Te results of a SEEPFINDER survey will provide further insight and assessment of the geology and thus of the petroleum potential of an area. With direct access to the slick locations and their characteristics, exploration companies can analyse and plan more efficiently additional exploration activity in the region. GRAVEX is a system of individual gravity sensors mounted in an aircraft in a configuration that allows for a greatly enhanced processing of gravity data. Unlike other gravity gradiometer systems, GRAVEX
measures both gravity and gravity gradients. Soon to be available on a contract basis, GRAVEX is a unique combination of experience, new and existing technologies, all partnered with a new method for using them, with the whole concept protected by patent.
Fig. 1. Examples of light, mid, heavy analysis and composite maps for a region of seepage in the North Atlantic Margin.
GRAVEX is a multi-sensor approach to the measurement of gravity gradiometry, applied over a much larger baseline - typically approaching the dimensions of the aircraft hosting the system. Te survey aircraft is fitted with wing pods, aerodynamic wingtips and a tail ‘stinger’ housing a high- sensitivity magnetometer.
Fig. 2. Composite seep data (left) and aeromagnetic data (right).
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