天然氡气法测岩石孔隙度方法研究

为了探索既不改变原有孔隙、又不污染岩石的孔隙度测定新方法,以岩石中天然放射性同位素镭22688　Ra递次衰变释放出的氡气替代常规孔隙度测定中的注入或饱和流体,进行了岩心孔隙度测定方法的新尝试。实验测量结果和理论分析表明,天然氡气法能够有效地测定具有一定天然放射性水平岩心的孔隙度,并特别利于于驱替后岩心的残余流体饱和度的测定。但是,该方法受到岩心中天然放射性核素含量的影响。对此,提出了改进措施。

STUDY ON NATURAL RN METHOD FOR MEASURING CORE POROSITY

An experimental investigation has been conducted to ex-plore a novel method for measuring the porosity of core samples,which will not both pollute the core and change the original porosity of the core. The method takes advantage of measuring natural Radon(Rn) from the radioactive decay of radioisotopeRadium in the core sample instead of fluid injection /saturation as in common porosity measurement. Experimental results and theoretical analysis show that the new method can effectively measure the porosity of a core with a certain intensity of natural radioactivity, and has the special advantage for determining the residual fluid saturation of a core after displacement. As themethod would be limited by the content of the natural radioiso-tope in the core sample, measures for further improvement of the method are proposed.