Abstract: Fracture-cavity reservoirs of Ordovician carbonate rock in Tahe oilfield have various types and complex structures. Acoustic remote detection technology can detect geological anomalies in the range of tens of meters outside the well, and has broad application prospects in the evaluation of fracture-cavity reservoirs. Firstly, the staggered grid finite difference method with perfectly matched layer (PML) absorption boundary conditions is used to simulate the acoustic remote detection logging response of fracture-cavity reservoirs in Tahe oilfield. Then, through the simplified modeling of fracture-cavity spatial distribution, the fracture distribution model with different lengths, openings and angles of  fractures passing through and beside the well and the fracture-cavity reservoir model with the changes of cave, hole size, number and distance beside the well are established. Then the wave field is simulated by finite difference, the wave field characteristics of cracks, caves and dissolution holes are analyzed, and the imaging results of cracks, caves and dissolution holes of acoustic remote detection  wave field are obtained by offset imaging processing method, and the corresponding imaging interpretation model of acoustic remote detection is established. At last, the acoustic remote detection logging data of real drilling are compared with conventional logging, electric imaging logging, seismic profile characteristics, and oil test results. The results show that the acoustic remote detection interpretation model established by this method is effective for the identification and evaluation of carbonate fracture-cavity reservoirs.

Key words: Tahe oil field, fracture-cavity reservoirs, acoustic remote detection, numerical simulation, interpretation model, example application