Linking rock physics and basin history — Filling gaps between wells in frontier basins

Abstract

A method has been developed to link present-day well or seismic measurements through rock-physics temperature and net-erosion variations caused by past tectonic events within a sedimentary basin. An ambiguous and intricate link among physical rock properties, temperature history, and burial history is demonstrated by modeling examples. Net-erosion estimates presuppose an estimate about temperature history and vice versa. Net erosion and temperature history normally cannot be estimated independently when using elastic rock properties, although net erosion in principle can be estimated independently of temperature for shallow unconsolidated sediments. For rocks that have been subjected to thermal diagenesis, either net erosion or paleotemperature must be known by consensus while estimating the other, or both must be estimated simultaneously. Well data demonstrate how rock physics is used to predict the maximum historical temperature and net erosion based on well-log velocities. From these parameters, sediment cooling can be derived. These estimates can be performed away from well positions, based on seismic velocities in shale. Temperature and erosion estimates are given for a 2D line, and large lateral variations are estimated. Normally, if well data are sparse, there will be a high uncertainty in net-erosion estimates. The new method reduces uncertainty in net-erosion and temperature estimates in areas away from well control. The method is used in an area with good estimations of uplift and erosion from wells and gives results consistent with observations.