用声波时差资料研究泥岩压实时的岩性影响问题

LITHOLOGIC EFFECTS UPON THE STUDY OF CLAYSTONE COMPACTION USING THE DATA FROM TIME DIFFERENCE OF ACOUSTIC WAVE

使用声波时差测井资料来了解泥岩孔隙度,从而研究泥岩压实状况,是以泥岩的岩性均一为基础的.中国东部陆相盆地中泥岩含砂比较普遍,泥岩中粉砂含量的变化给时差读数带来了明显的影响.但这种变化不能用自然伽玛和自然电位资料加以识别,常常为一些研究者忽视,由此在时差取值、选取正常趁势线和资料的地质解释工作中造成一些错误.本文依据声波时差测井的物理基础和岐北凹陷的实际资料对这些问题作了分析,并提出了解决问题的方法.

Based on the lithological homogeneity of claystones, logging data of time difference of acoustic wave have been used to study the porosity and compaction of claystones. The claystones in the continental basins of Eastern China are often sand-bearing. The readings of time difference can be strongly affectted by the variation in silt content of claystones. This is likely being neglectted, because it can not be identified from the informa-tion of natural potential logy. There are possibilities of error in selecting values of time difference and normal trend lines, and in geological expla-aination as well. The authors analyse these problems using acoustic log and actual information from the Qibei Depression and propose the right way to solve such problems.