Perpustakaan Digital ITB

Fracture is one of the most important migration channels and accumulation spaces in hydrocarbon reservoirs. For unconventional hydrocarbon reservoirs, especially shale reservoirs, the accurate prediction of fracture distribution can help to improve the hydrocarbon production. With the development of seismic monitoring techniques, wide azimuth acquisition and processing techniques are being increasingly used to describe the distribution of subsurface factures. The P-wave AVAZ inversion based on seismic anisotropy is one of the most important and commonly used methods for fracture prediction. In this paper, we develop an inversion algorithm to acquire the normal and tangential fracture weaknesses based on P-wave reflection anisotropy and wide azimuth seismic data. The newly developed algorithm can perfectly utilize the amplitude information of large offset data to retrieve the fracture weaknesses of reservoirs which are related to fracture density and fluid fillings. Numerical model test and a 3-D synthetic data example show that the fracture weaknesses can be accurately estimated by using the newly proposed AVAZ inversion method. Our inversion method can obtain reliable fracture identification results even when the seismic data is contaminated by random noise, which demonstrates the reliability and noise resistance of the inversion method. Finally, the method is successfully applied to a 3-D physical model data with an equivalent area of 100?km2. The predicted fracture distribution result is consistent with the designed physical model and is highly related to the local geological structures of the target reservoir. Though numerical and physical model studies, we demonstrate that the proposed inversion method is an effective approach to directly evaluate the fracture distribution in the reservoir.