海底沉积物声学原位测量方法与南海天然气水合物勘探的应用研究

Study on Acoustic In-situ Measurement Method of Marine Bottom Sediment and Application in Detection of Hydrates in the South China Sea

研究原位测量技术中表层沉积物声学原位测量技术、声波测井技术和OBS测量技术的特点和差异,得出3种技术的分辨率虽然依次降低,但测量尺度依次增大,可以应用不同深度和结构层序的海底沉积物声学物理性质研究。3种原位测量技术基于海底原位状态,可以测得海底沉积物的纵波和横波特性,通过比较纵波特性、纵横波速比和计算泊松比可以提高沉积物中分辨出天然气水合物的精度。基于OBS测量技术可以同时实现水合物的勘探与监测,基于表层沉积物声学原位测量技术和声波测井技术可以同时实现原位测量和采样,3种技术结合可以促进南海天然气水合物勘探与监控的实际应用。

The research is placed emphasis on characteristic and difference of the seafloor sediment acoustic in-situ measurement technique,acoustic logging and ocean bottom seismometer（OBS） technology.The conclusions could be drawn that the three techniques decrease in the resolution but increases in the measurement scale which can be applied to research of physical and acoustic properties of seafloor sediment in different sequences and depth.The in-situ measurement techniques penetrate into the in-situ seafloor state and can measure rotational and longitudinal wave properties of sediments.By comparing the longitudinal wave characteristics,longitudinal and rotational velocity ratio and calculation Poisson＇s ratio,the accuracy could be improved in distinguishing gas hydrate.Measurement technique based on OBS can achieve both hydrate exploration and monitoring.The in-situ surface sediment acoustic measurement technique and acoustic logging technology can achieve both in-situ measurements and sampling.The combination of the three technologies can contribute to gas hydrate exploration and monitor the actual application in the South China Sea.