不同渗透压力下盐岩的渗透率测试研究

RESEARCH ON PERMEABILITY TESTING OF ROCK SALT UNDER DIFFERENT PERMEABILITY PRESSURES

地下盐腔被广泛应用于核废料地下处置、石油天然气地下储存和二氧化碳封存,由于盐岩的低渗透性,目前很难通过试验获得其渗透率。通过稳态法对3种不同成分盐岩进行渗透特性试验研究,获得盐岩的渗透参数,并对拟压力法和考虑克氏效应的2种渗透率计算方法的结果进行对比研究。结果表明:(1)盐岩的渗透率与孔隙度极低,孔隙度为0.3%～3.0%,纯盐岩渗透为10-20m2左右,而含杂质盐岩渗透率更低,为10-20～10-21m2;(2)对盐岩的气测渗透率进行测试,进气压力为1～5 MPa时,Klinkenberg效应影响明显,当渗透力超过5 MPa后,岩体在渗透力作用下会产生损伤,渗透率升高;(3)通过对比,考虑Klinkenberg效应的方法较拟压力法在盐岩渗透率计算中更为理想。

Rock salt cavern is widely used for nuclear waste disposal,petroleum and natural gas storage and CO2 sequestration.The permeability of rock salt is too low to be obtained easily by experiments.The permeability of three different rock salt samples are obtained through the steady-state method.The permeability calculated by pseudo-pressure method and considering Klinkenberg effect are compared.The results show that：（1） The permeability and porosity of rock salt are extremely low,and the porosity is between 0.3% and 3%.The permeability of pure rock salt is about 10-20m2,greater than that of impurity rock salt,which is between 10-20and 10-21 m2.（2） During the permeability experiment,when the inlet pressure is 1–5 MPa,Klinkenberg effect is obvious.When the inlet pressure is higher than 5 MPa,the rock salt is damaged and the permeability increases.（3） By comparing the results,the method of considering Klinkenberg effect is more ideal than pseudo-pressure method in rock salt permeability calculation.