Method for monitoring hydraulic fracturing range of surface vertical shaft

A method for monitoring hydraulic fracturing range of a surface vertical shaft, comprising the following steps:

• S1:
• taking a wellhead of an ultrahigh-pressure hydraulically fractured well as an original point, drilling surface monitoring holes having a diameter of 90 mm, for installing micro-seismic deep hole geophones, at intervals of 50 m according to a direction of a working face strike towards a cutting hole, wherein a total of three monitoring holes are drilled, namely, a 1# surface monitoring hole, a 2# surface monitoring hole, and a 3# surface monitoring hole respectively;
• S2:
• drilling three surface monitoring holes in a propelling direction of the surface fracturing hole towards the working face according to the same drilling method as S1, namely, a 4# surface monitoring hole, a 5# surface monitoring hole, and a 6# surface monitoring hole;
• S3:
• implementing two monitoring holes in directions of vertical working face strikes on the two sides of the wellhead of the ultrahigh-pressure hydraulically fractured well by adopting the same method as S1, namely, a 7# surface monitoring hole, and a 8# surface monitoring hole, wherein the 7# surface monitoring hole and the 8# surface monitoring hole are both 60 m away from the wellhead of the ultrahigh-pressure hydraulically fractured well, and drilling depths of which are 20 m and 30 m, respectively;
• S4:
• taking the wellhead of the ultrahigh-pressure hydraulically fractured well as the original point, constructing a monitoring well at a distance of 130 m from the strike of the working face, and placing geophones between key strata. S5:
• drilling downhole monitoring holes at an inclination of 75° to the coal wall in the working face cutting hole and a solid coal gateway, and installing micro-seismic deep hole geophones at the hole bottoms, each downhole monitoring hole having a hole depth of 25 m;
• providing the downhole monitoring holes at intervals of 50 m in a track gateway direction and a transport gateway direction, with four downhole monitoring holes in each direction;
• S6:
• after the normal installation of the micro-seismic deep hole geophones is ensured, laying a communication cable from the micro-seismic deep hole geophones to the surface portable high-precision micro-seismic monitoring system and a communication cable from the micro-seismic deep hole geophones to the downhole portable high-precision micro-seismic monitoring system uphole and downhole, respectively;
• S7:
• communicating the surface portable high-precision micro-seismic monitoring system and the downhole portable high-precision micro-seismic monitoring system with the micro-seismic deep hole geophones and debugging the micro-seismic deep hole geophones, thus ensuring that the geophones are normal and the wire connection sequence is correct;
• S8:
• accurately measuring orifice coordinates of each micro-seismic deep hole geophone and calculating the coordinates of the micro-seismic deep hole geophone, and inputting the coordinates into the correspondingly connected portable high-precision micro-seismic monitoring system;
• and
• S9:
• testing the fracturing effect, after the hydraulic fracturing starts, performing monitoring by the surface portable high-precision micro-seismic monitoring system and the downhole portable high-precision micro-seismic monitoring system at the same time, performing micro-seismic event accurate positioning according to the micro-seismic event and time of each micro-seismic deep hole geophone recorded by the portable high-precision micro-seismic monitoring system, thus obtaining the development range of fractured fissures.