REIJS, JURRIAAN P. J.¹, KEN R. MCCLAY², and DICK A. NIEUWLAND^1
1Shell International Exploration and Production BV, Rijswijk, The Netherlands
²Department of Geology, Royal Holloway, University of London, Egham, UK

Abstract: 4D Analogue Models of Starved Strike-Slip Pull-Apart Basins

The application of videolaser and time-lapse X-ray Computerized Tomography scanning techniques in conjunction with seismic imaging software to the analysis of strike-slip analogue models has provided new detailed insights into the 4D architecture of pull-apart systems. These techniques generated spectacular images, showing how faults grow in 3D by coalescence of early-formed fault segments. The models indicate that starved pull-apart basins preserve relay ramp softlinkage structures in the basin sidewall fault system. The basins are bound by terraced basin sidewall faultscarp systems and have a segmented, highly deformed basin interiors with welldeveloped basin shortcut fault systems. In mature starved basins, strain is partitioned between the strike-slip short-cut fault systems and large extensional basin sidewall fault systems. The experiments show how the flower structures can dramatically change along both strike and dip, from curved to planar faults and from convex to concave upwards fault geometries, which give rise to strong along-strike variations in the tilts of individual fault slices.

The 3D network of linked fault segments in a pull-apart basin controls reservoir compartmentalization, fracture porosity and hydrocarbon migration pathways. Understanding the architecture of such complex 3D fault networks, provides a template for the interpretation of strike-slip terranes where the (seismic) data resolution and quality are poor.

AAPG Search and Discovery Article #90928©1999 AAPG Annual Convention, San Antonio, Texas