Identification method of hidden structure reactivation based on microseismic and numerical simulation

Abstract

The microseismic monitoring can be used to identify and predict the activations strength of rock breaking, faults or hidden structures, and the use of numerical simulation technology can realize the inversion and reproduction of the stress field in the structural activation zone, the two complement each other, which can realize stress disturbance- stress concentration- local micro fracture- stress migration captured from internal cause to the appearance in the whole activation process of hidden structure. Based on the production and geological conditions of 1612A working face in Zhangji Coal Mine of Huaihe Energy Group, and the microseismic(MS) monitoring system, the temporal and spatial distribution characteristics of MS events were analyzed in the stope. The relationship between microseismic activity and fault activation was explored. And the identification method of hidden structure activation was proposed with the inversion of numerical simulation based on the MS data. The results show that, the MS events in the stope had typical time-phased and spatial regional distribution characteristics. Combined with the source parameters, it is determined that there is an abnormal area near the faults of F1611A76-F1611A7677, which was suspected to be a derivative fault of these faults. Through numerical simulation of the stress changes under two conditions to respond to the energy release law, the inversion results indicated that there were hidden structures in the measured area. Through field survey and trough wave geophysical exploration, it was found that there were typical broken abnormal areas in the specific range, which further verified the feasibility and accuracy of MS monitoring combined with numerical simulation to identify the activation of hidden structures.

Keywords

• microseismic monitoring
• spatiotemporal characteristics
• hidden structure
• reactivation
• stress evolution