Non-linear Analysis of Low-frequency Microseismic Background

Low frequency seismic data were analyzed with the help of non-linear Grassberger-Procaccia method. Two data sets were considered: microseismic background inside and outside gas field (“passive” method) and the microseismic background recorded before and after vibrations over an oil field with complicated unknown boundaries (“active” method). It was found, that an application of non-linear methods has to be done with caution. Only the analysis of the records containing pulses allowed to distinct the microseismic background inside the gas field from the background outside the field. The analysis of the records obtained after the vibrator works showed an appearance of deterministic component in the microseismic background after the vibrations at several studied points. Two wells were drilled in proposed points, and the both were successful.