结晶岩的膨胀性能研究

采集了来自德国大陆深钻（ＫＴＢ）中的一组结晶岩，在实验室用位移记录仪或应变片接通电桥测量了岩石浸入不同流体中应变随时间的变化．结果表明：１．不同的岩石浸入水中，其膨胀速率和膨胀量是不同的，这与岩石的孔隙结构有关．２．同一岩样浸入极性和非极性的流体中，其膨胀性能是不同的，这与水分子的极化特性及其表面张力有关．３．很多情况下，膨胀是各向异性的，尤其是片麻岩．因此体积的增长可根据在３个互相垂直方向上的相对长度变化的总值来计算．可以认为，膨胀的主要因素是极性流体与岩石颗粒作用的结果，膨胀性能是由于颗粒表面的双扩散层造成的．实验证实了地壳岩石变形的机制强烈地受到流体的存在与否以及不同类型流体的影响．流体与岩石间相互作用的研究将对深入探讨地壳内流体的热过程、力学过程、油气运移以及岩石物理性质有重要意义．

SWELLING BEHAVIOUR OF CRYSTALLINE ROCKS

Continental scientific drilling(CSD)is a important part of Intenatlonal Lithosphere Geodynamic Program,it is also one of the current key frontier geoscience.The investigation were carried out on crystalline rocks collected from continentalscientific deep drilling program(KTB)in Germany.The deformation with timewas measured with strain gauges or a displacement transducer.The results of study suggest that:(1)The soaking rate can differ for various rocks.It is related to the pore structure of rocks.(2)Very important for the swelling behaviour Is the polar character of the water molecule.Experiments with nonpolar fluids like heptanor benzine showed no or only very small swelling.(3)In many cases the swelling is anisotropic particulary for gneiss.The volume increase was calculated from thesum of the relative elongation in three orthogonal directions.So the osmotic swelling originates from the diffuse double layer atsurface.The experiments show thatthe influence of fluid and diffrent fluid types on the deformation of rock in earth crust.Study on interaction between rock and fluids is of important significancefor study thermal process & gas,and petrophysics.