Seismic Monitoring the Variations of Open Fracturing of Reservoir Rocks due to Lunisolar Tides

Studied is the dynamics of natural variation of open fracturing of petroleum reservoirs caused by lunisolar tides. Experimental seismic studies were performed by monitoring the fracturing using Side-View Seismic Location (SVSL) and Seismic Location of Emission Centers (SLEC) - active and passive seismic methods, respectively. A periodic variation of open fracturing intensity is established with maximums of open fracturing correlating with maximums of gravity gradients. It is found that the largest variations are predominantly characteristic for subvertical fractures and the role of fracturing variation is crucial for deep-seated reservoirs. The effect of natural time variations of open fracturing should be taken into account when performing reservoir stimulation and during oil recovery and water injection to provide the high efficiency of production especially for mature oil fields where such operations are common.