Method for calculating longitudinal wave velocity of mudstone stratum by using engineering parameters

The invention discloses a method for calculating the longitudinal wave velocity of a mudstone formation by using engineering parameters, which comprises the following steps of: collecting formation pore pressure, acoustic logging, caliper logging and debris logging data of a drilled well, and extracting formation pore pressure and longitudinal wave velocity data of a mudstone formation of an unexpanded section of the drilled well; establishing a quantitative relation between the formation pore pressure and the longitudinal wave velocity of the drilled mud rock stratum by referring to the proposed regression model; obtaining while-drilling engineering parameters and rock debris logging data of a drilling well, and extracting rock drillability parameters of a mud rock layer of the drilling well; on the basis of an Eaton method, the formation pore pressure is calculated through the rock drillability parameters of the drilling mud rock stratum; and calculating the longitudinal wave velocity of the drilling mud ro