--> ABSTRACT: Slide Masses in a Chalk Environment, by Peter Britze, Erik B. Nielsen, and Thomas Tygesen; #90906(2001)

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Peter Britze1, Erik B. Nielsen2, Thomas Tygesen3

(1) Geological Survey of Denmark and Greenland (GEUS), Copenhagen, Denmark
(2) Geological Survey of Denmark and Greenland, Copenhagen, Denmark
(3) Amerada Hess A/S, Copenhagen, Denmark

ABSTRACT: Slide Masses in a Chalk Environment

Based on several chalk studies carried out at The Geological Survey of Greenland and Denmark (GEUS), it has been possible to accomplish the first rather detailed identification of chalk slides from the Danish and Norwegian North Sea. An integrated description of slides will be given from their apparent 2D and 3D seismic expression, through the distinct well-log patterns of the sonic and gamma-ray logs, to the core description. The recognition of the dimensions, the internal structures and textures and the upgraded porosity of the slides will be discussed. An example of a chalk slide is recognised at the 2/6-3 well, Norway. The slide interval in the well is 55 m thick and occurs between low porosity hard beds. The length of the slide is about 3 km, the present day thickness is at the head (scar) 0 m, at the tensional part 55 m, and 80 m at the toe or compressional imbricated part. The dimensions of this slide is comparable with the minor chalk fields of the study area. That the slide interval only has been slightly deformed may be inferred from the imbricated structure in the toe of the slide. As indicated by the well logs, seismic reflectivity, and inversion, the slide is more porous than the surrounding bedrock's. The higher porosity, in the slide interval points to a disruption caused by the movements of the slide. The recognition of slides with preserved porosity could be a supplementary play to explore down-flanks of exiting chalk fields.

AAPG Search and Discovery Article #90906©2001 AAPG Annual Convention, Denver, Colorado