关键词: 分布式光纤, 声波, 油气勘探, 相位调制解调, 声压灵敏度, 瑞利散射

Abstract: As conventional and easy-to-extract oil and gas resources are declining, the exploration and exploitation of oil and gas resources in complex geological areas will play an increasingly important role in reducing our country′s dependence on foreign oil and gas and ensuring national energy security. Oil and gas reservoirs in complex geological areas have the characteristics of thinner, deeper, and stronger heterogeneity. Effective exploration is difficult to achieve using the existing seismic wave detection technology. In this paper, a distributed optical fiber acoustic wave sensing system for oil and gas seismic wave exploration and exploitation is designed. An optical cable is used as the sensor to detect the sound signal. Phase modulation/demodulation technology based on Rayleigh backscattering is adopted in a sound pressure sensitivity test that achieved a spatial resolution of 10 m and -145.35 dB. Further, field seismic exploration was conducted, seismic wave signal acquisition and processing were completed, and clear stratum information was obtained.

Key words: distributed optical fiber, acoustic wave, oil and gas exploration, phase modulation and demodulation, sound pressure sensitivity, Rayleigh scattering