Ľ Analyse Des Films Reels Et Leur Comparaison Avec Les Films Syntetiques

Abstract

The practical use of synthetic records involves previous studies on field records from an original point of view ; these studies consist essentially in analysing and cancelling noise, in bringing out the form of pulses and the character of seismic events, in detecting multiple arrivals. Various tools have been tested for this purpose: high multiplicity shooting, analysis of conventional well velocity surveys, mixing or selecting traces, varied filters; a11 these operations are facilitated by the use of magnetic recording. After several examples of these methods are given, it is shown how the results of such studies cari help to make and discuss synthetic records with and without multiples. The share of multiple events and their effect on the efficiency of the later comparisons are especially treated.The authors finally present some specific examples of successful comparisons between synthetic records and field records treated beforehand.They insist on the discrepancies and on the importance of finding their origin, for the most tangible results in seismic interpretation generally appear during the analysis of such discrepancies. SOMMAIRE L'utilisation pratique du film synthétique implique une étude préalable des enregistrements réels dans une optique très différente de la routine. Il s'agit essentiellement d'analyser et d'éliminer le bruit, d'en dégager la forme des signaux sismiques et le caractère des réflexions, de détecter les miroirs multiples. Les procedés employés dans ce but sont très variés: tirs de supermultiplication, examen des arrivées tardives dans les carottages sismiques conventionnels, composition ou sélection des traces, filtrages divers; toutes ces operations sont facilitees par l'enregistrement magnetique.