Oil well cement composite permeation enhancement agent suitable for hydrate layer and preparation method

An oil well cement composite permeation enhancement agent for a hydrate layer, wherein, in parts by weight, a composition of raw materials of the oil well cement composite permeation enhancement agent is 4.6 parts-5.0 parts of kerosene, 0.23 parts-0.25 parts of an emulsifier, 0.8 parts-1.1 parts of a surface-modified polypropylene fiber, 10.0 parts-12.0 parts of porous and permeable microspheres, 1.0 part-1.2 parts of paraffin, and 57.5 parts-62.5 parts of water;

• wherein a length of the surface-modified polypropylene fiber is 5 mm-6 mm, a diameter of each of the porous and permeable microspheres is 0.27 mm-0.55 mm, and an aperture of each of the porous and permeable microspheres is 0.15 mm-0.25 mm;
• a specific preparation process of the surface-modified polypropylene fiber is as follows:
• first, swelling a polypropylene fiber with a xylene for 60 min-80 min, then taking it out and filtering to dry to obtain a first resulting fiber;
• soaking the first resulting fiber in an acetone solution for 3 h-4 h, then washing with a distilled water and drying in an air to obtain a second resulting fiber;
• followed by soaking the second resulting fiber with a silane coupling agent with a concentration of 50% for 120 min to modify and optimize a surface of the polypropylene fiber to obtain a third resulting fiber;
• after a modification is completed, washing the third resulting fiber to be neutral with the distilled water and drying to obtain the surface-modified polypropylene fiber;
• finally, blowing the surface-modified polypropylene fiber into a root shape with an air gun and packing for a set aside.