PREPARATION METHOD FOR LARGE MODEL MICROCRACK ROCK CORE HAVING LOW PERMEABILITY

摘要

A preparation method for a large model microcrack rock core having low permeability, comprising: (1) determining the size of a microcrack rock core to be prepared; (2) placing pebbles in an oven to dry at 120°C for 24 hours, then placing into a mixer and spraying oil while stirring such that the oil seeps into the pebbles to evenly form a thin oil film on a surface of the pebbles; (3) mixing and stirring the oil-sprayed pebbles, quartz sand, and cement, then adding water and stirring evenly to obtain a cement slurry; (4) greasing an inner surface of a rock core mold such that the inner surface of the rock core mold is provided with a thin layer of an oil film, pouring the cement slurry into the rock core mold to obtain a cement sample; (5) according to the requirements of model porosity and permeability, applying peripheral pressure on the exterior of the rock core so as to adjust a porosity and permeability value; (6) after the cement sample is dried and formed, then obtaining a large model rock core having microcracks. The method uses simple materials and is low cost while operation is easy; microcracks having multiple shapes and random distribution may be formed in the large model rock core, which may better simulate the development process of microcrack resevoirs.