Manufacturing method of big-model low-permeability microcrack core

A manufacturing method of a big-model low-permeability microcrack core, comprising the following steps successively:

• (1) determining a size of a microcrack core to be manufactured;
• (2) placing a plurality of stones in a baking oven to bake for 24 h under 120° C., after baking, placing the plurality of stones into a mixer, mixing and spraying an oil, and keeping the mixture of the plurality of stones and the oil for 2 h after mixing evenly to enable the oil to seep into the plurality of stones and evenly forming a layer of thin oil film on a surface of the plurality of stones;
• (3) mixing the plurality of stones sprayed by the oil in step (2) with a quartz sand and a cement, and then adding water and mixing evenly to obtain a cement paste;
• (4) spreading a butter on an inner surface of a core mould to form a layer of thin butter film on the inner surface of the core mould, pouring the cement paste in step (3) into the core mould, and vibrating the cement paste in the core mould by a vibrating rod during pouring to obtain a cement sample;
• (5) loading a predetermined confining pressure outside the core according to a degree of porosity of the mould and the permeability after pouring, so as to adjust a pore permeability value;
• and
• (6) forming the big-model low-permeability microcrack core after drying the cement sample.