Skip to main content
European Commission logo print header
Contenu archivé le 2022-12-27

VERTICAL SEISMIC PROFILE TECHNIQUES AND SURFACE SEISMIC RECORDING IN COMPRESSION AND SHEAR WAVES IN THE FIELD

Objectif

To study how vertical and surface seismic profiles may help in the detailed determination of gas reservoir characterics.
On the p sections the resolving power of the order of 4-6 m, both with the vibrator and soursile. However, the presence of the gas did not generate any bright spot. This rather surprising fact was attributed to a rather heterogenous diffusion of the gas through the reservoir layer.
Owing to the lack of penetration of the s waves, study of the reservoir by means of a comparison of p and s reflections did not possible. A comparison of the spring and autumn p and s reflections did not enable any reflectivity variations to be detected on the reservoir upper limit. It was therefore decided to conduct detailed comparisons of p time interval between one reflector above the reservoir and another one below it. Great care was taken to eliminate all causes of time variation other than that due to the presence or absence of gas. It was found that at places where a movement of gas-water front occurs, the time interval is greater in autumn than during the spring. Systematic, very small deviations were observed, of the order of one millisecond or less. Albeit small, they seem to be meaningful because of their correlation with the gas buble location.
An artificial underground gas storage was selected for experiments, as the geology is very well known because of the large number of wells drilled on the structure. Seismic lines were shot in 1980 in the n.W.Part of the gas storage and in 1981-1982 in the s.E. Part of the same structure. P wave lines were recorded with a high resolution vibrator using a 32-160 hertz sweep and soursile, a high weight-drop source. S wave line were abtained with marthor and soursile ps, both of them weight-drop sources generating transverse waves with horizontal polarization. Three vertical seismic profiles were recorded with p and s waves in one welll with various reservoir saturations.

Appel à propositions

Data not available

Régime de financement

DEM - Demonstration contracts

Coordinateur

GERTH
Contribution de l’UE
Aucune donnée
Adresse
232 av. napoleon bonaparte
92500 Rueil malmaison
France

Voir sur la carte

Coût total
Aucune donnée