The invention relates to a drilling liquid leakage prediction method for fissured formation, and belongs to the field of
petroleum and
natural gas drilling engineering. The method comprises the following steps that A, the width w of various fissures is calculated; B, the consistency coefficient k of a
drilling fluid, the flow behavior index m and the
drilling fluid yield stress tau<y> are measured; C, the formation pressure p is calculated; and D, the leakage of the
drilling fluid is calculated according to a formula, a drilling
fluid leakage model is obtained though the following method that the drilling fluid
mass conservation equation, the leakage
momentum equation, the rheological equation of a fluid and the
tortuosity equation are solved simultaneously to obtain a formula (18) anda formula (23), the formula (18) is the relationship between the
differential pressure and the leakage
radius, and the formula (23) is the total leakage relationship of the drilling fluid. According to the drilling
fluid leakage prediction method for the fissured formation, the leakage of the drilling fluid of the fissured formation can be predicted, so that a field engineer adopts a reasonable and efficient leakage stopping technology in time according to the loss condition of the formation, solves the drilling risk in time, and reduces the loss of the drilling fluid.