CT扫描方法在东海泥质沉积物孔隙度分析中的应用与对比

Application of X-ray computed tomography to porosity analysis of the along-shelf clinoform deposit in the East China Sea

孔隙度作为海底沉积物的一项重要物理参数,其传统获取方法存在着一定的不足。本研究利用医学CT扫描技术对采自东海内陆架泥质沉积区的一沉积物岩心SS4进行了测试,提取了垂直方向上沉积物的CT值。通过CT值与部分孔隙度及环刀实验获得的孔隙度之间相关性的比较,建立了东海泥质区沉积物CT值与孔隙度之间的经验公式。同时,研究还发现CT扫描对于沉积物垂向上结构不均一的岩心,CT值与孔隙度之间的相关性较差,这并非方法和精度的问题,而是由于取样点结构不一致造成的,因此根据相关性好的层段拟合的经验公式具有更高的可靠性。作为一种快速、无损的测试和观测手段,CT扫描在沉积物岩心研究中将提供更多有用的帮助。

Porosity is an important physical parameter of seabed sediments.However,the traditional method for porosity acquisition remains insufficient.In this study,we measured the porosity of the sediment core SS4 taken from the along-shelf clinoform deposit in the East China Sea with a medical CT-Scanner,and extracted the CT numbers one by one in vertical direction.By comparison of the CT numbers with the porosities obtained from the tube method,an empirical formula is derived between CT number and porosity for the clinoform deposit in the East China Sea.It is found that the CT number is poorly correlated with the porosity acquired from the tube method,when the vertical composition of the core was inhomogeneous,owing to the texture inconsistency of samples.However,the empirical formula acquired from the core sections where occur high correlations between CT numbers and porosities should have higher reliability.Thus we recommend the CT scanning method as a fast and nondestructive method for measurement and observation of sediment porosities.