Objective Develop and market a seismic data acquisition system to record a large number of channels (up to 480). This system must avoid the drawbacks of multipair cables, i.E. Leakage, cross-talk and industrial noise pick-up. The project could be devided into three main parts: - analog data aquisition: This part includes low cut and anti-alias filters: it has to handle low level signals (down to .15 uv) with a wide dynamic (up to 110 db). The signals are converted to digital in floating point (15 bit mantissa, 4 bit gain) with a special-converter. - digital data transmission: After analog to digital conversion the seismic data is transmitted on a two pair cable down to a central unit at a rate of 4 mbits-s. This data transmission requires special integrated circuits to permit a transmission with a ber better than 10-9 although the power drain remains very low (100 mw). - central unit: A minicomputer-based central unit controls the whole data acquisition and performs all the tests. It has to format the data to make it possible to record a geophysical tape with the 6250 bpi gcr standard. RESULTS: At the beginning of 1984, 107 sn 348 were in operation with other 28 000 field units. The sn 348 is used in every king of oil seismic exploration apart from deep-water operations in all environments. The ability to record a large number of channels with immunity from cable noise is greatly appreciated by the users. Programme(s) ENG-HYDROCARB 1C - Programme (EEC) of Community projects in the hydrocarbons sector, 1973-1985 Topic(s) Data not available Call for proposal Data not available Funding Scheme Data not available Coordinator COMPAGNIE GENERALE DE GEOPHYSIQUE/SERCEL EU contribution No data Address RUE DE BEL AIR CARQUEFOU 44470 NANTES France See on map Total cost No data
