土酸对页岩溶蚀率影响的试验研究

An experimental study on the influence of mud acid on the dissolution rate of the shale

利用X射线衍射晶体鉴定技术,首先确定页岩试样主要矿物成分,根据矿物成分确定酸化试验所用的酸液。利用质量分数为3%的HF和10%的HCL混合而成的土酸溶液酸化20mm×20mm×50mm的块状的钠长石、石英试样。利用超景深三维显微系统初步分析试样表面的腐蚀程度,并用Image-Pro Plus计算表面积溶蚀率的变化以及测量pH的变化规律,以分析页岩酸化的机理。设置对比实验,确定HF和HCL分别对溶液的贡献。本文是酸化压裂对含气页岩渗透性能的影响的基础室内试验研究,研究成果可以为实际工程应用提供理论依据。

By means of the X-ray diffraction crystal identification technology, the main mineralcompositions of the shale specimen was determined,which leading to the selection of the mixed acid solution.The mass fraction is 3% and 10%for HF and HCL in the mixed acid,respectively,to treat bulk albite and quartz specimen with the size of 20mm×20mm×50mm.In order to analyze the mechanism of the shale acidification,utilize the hyper-focal distance digital microscope system to observe the corrosion,and employing Image-Pro Plus software to calculate the variation rate of the surface area corrosion as well as measure the change law of the PH.By performing the comparable tests,it was confirmed that the HF＇s and HCL＇s contributions to the mixed acid respectively.This laboratory experiment research is a preliminary study that the influence of the acid fracturing on the permeability forgas shale,and the research results will provide theoretical basis for applications of practical engineering.