The invention designs a method for monitoring an
oil well fracturing microseismic ground-borehole crack, which is characterized by comprising the following steps of: receiving microseismic
waves by monitoring substations arranged at the circumference of a
wellhead by utilizing the propagation characteristic of an elastic
wave field in a stratum medium, forming a series of equation sets according to the
arrival time difference of the microseismic
waves of each substation, and solving the series of equation sets to determine the position of a microseismic source and further determine stratum parameters of crack distribution, such as the
azimuth, the length, the height, the ground stress direction and the like. The
background noise in a well is small,
filtration processing is carried out on a ground observation
signal through an underground observation
signal, fracturing microseismic signals and ground interferences are screened and distinguished, a
detector placed in the well is a reference value of a whole set of
system collected signals, the
signal collected by a ground
seismometer is identified by people through the reference value to filter an interference signal, so that a monitored result of the people can be more true and reliable.