Method and device for evaluating capillary self-absorption capacity of oil and gas well working fluid

The invention belongs to the technical field of petroleum engineering, and particularly relates to a method and device for evaluating the capillary self-absorption capacity of oil and gas well working fluid. The method comprises the following steps: S10, placing a test piece with a capillary bundle in a working solution, and enabling at least one part of the capillary bundle to be immersed in the working solution; s20, the rising condition of the working solution in the capillary bundle is observed, self-absorption rising characteristic parameters of the working solution in the capillary bundle are obtained, and the self-absorption rising characteristic parameters are used for indicating the self-absorption trend and the self-absorption strength of the working solution; s30, different working solutions are replaced, and operation from the step S10 to the step S20 is repeated; and S40, comparing the self-absorption trends and the self-absorption intensities of different working solutions in the capillary tube