Determination of palaeostresses from mesoscale shear fractures in core samples using the multi-inverse method

摘要

Palaeostress reconstruction is the key to quantitative characterization of fractured hydorcarbon reservoirs. In order to calculate the palaeostresses responsible for fault activity, fault in oriented core samples can be analysed and the optimal stresses can then be determined from fault-slip data in a least-squares sense. Many fractured reservoir rocks, however, include faults generated during a number of different tectonic phases. In these cases, the optimal stresses can be determined for subgroups of faults which are considered to be of approximately the same age. The difficulty with this is that criteria for accurate age-dating are often absent, especially form core samples.