测井和地震联合解释CCSD先导孔反射体

Joint Interpretation of Reflectors via Well Logging and Seismic Data in the Pilot Hole of CCSD

利用声波、密度、自然伽玛等测井曲线资料、配合录井资料划分CCSD先导孔变质岩岩性,然后,用声波、密度计算波阻抗,与井旁VSP资料对比,分析CCSD先导孔孔区反射体.分析结果表明(1)岩性间波阻抗差异产生反射波,如榴辉岩与副片麻岩之间波阻抗差异;榴辉岩与超基性蛇纹岩之间的波阻抗差异等;(2)破碎特别是韧性剪切带产生反射波,而如果断层破碎带尺度很小(在1m以下),也不一定能产生强反射波.这些研究结果对标定地壳中的反射地震信号具有重要意义.

The main aim of this paper is to analyze reflectors in the pilot hole of CCSD （China Continental Scientific Drilling）. The lithology of the metamorphite in the CCSD pilot hole can be identified by logging curves and geo-logging data. The wave impedance can be calculated by using acoustic （AC） and density log （DEN） curves. By comparing the acoustic wave impedance with the VSP （vertical seismic profile）, the reflectors of the CCSD pilot hole have been analyzed. The results indicate that reflected waves are primarily produced by the wave impedance properties of the lithology （such as the wave impedance difference between eclogite and paragneiss or between eclogite and ultrabasic serpentinite, etc） and the fracture. The fractures are mainly the ductile shear zones. If the fracture thickness is less than 1 m, reflectors cannot be produced. The study provides significant data concerning the interpretation of seismic reflection signals in the earth＇s crust.