Low-cost and low-friction drilling fluid suitable for shallow horizontal well and preparation method of low-cost and low-friction drilling fluid

The invention discloses a low-cost and low-friction drilling fluid suitable for a shallow horizontal well. The low-cost and low-friction drilling fluid specifically comprises the following components in parts by weight: 100 parts of tap water, 3-5 parts of bentonite for the drilling fluid, 0.15-0.25 part of sodium carbonate, 0.3-0.5 part of a coating agent for the drilling fluid, 0.3-0.5 part of a filtrate reducer for the drilling fluid, 0.7 part of a solid lubricant for the drilling fluid, 0.3 part of a liquid lubricant for the drilling fluid and 0.5-1.5 parts of a fluorescent-free anti-collapse agent for the drilling fluid, the invention also discloses a preparation method of the low-cost low-friction drilling fluid suitable for the shallow horizontal well. The drilling fluid provided by the invention has the advantages that the addition amount of a treating agent is small, and the cost of a drilling fluid system is low; the lubricating property is good, and the friction resistance is reduced; the environme