Equipment Testing and Optimization for Borehole Seismic Monitoring

With the advent of strong interests everywhere into unconventional – speak “shale” – reservoirs, the discipline of borehole geophysics is experiencing a remarkable renaissance. Particularly the fields of microseismic (MS) and vertical seismic profiling (VSP) are showing strong activities worldwide. Regardless whether one looks at MS or VSP, in order to properly interpret these borehole seismic data, one needs to rely on an optimal performance of the recording unit. While some parameters, such as sensor orientation or system noise levels, can be site dependent, there are a number of parameters the operator can influence to achieve a superior data record; laying the ground work for a more accurate event location or velocity model. In this work we present the results of a survey comparing a number of different downhole sensor arrays, excitation mechanisms and operational mechanics, with the goal to identify superior and inferior areas for the tools. The test was set up using a three well set up. The center well was used as a control well to obtain measurements that allowed us to use comparisons from consistent source readings. Those consistent source readings were compared with respect to the various arrays tested.