Currently

the problem of intra-well frac hit is serious in shale gas

which disturbs the production of nearby wells. Taking the Weiyuan national shale gas demonstration area as the research object

and according to the production characteristics of parent wells

quantitative evaluation index of intra-well frac hit influence based on the recovery rate of parent well production has been put forward. Then ten key geological and engineering parameters affecting intra-well frac hit influence have been analyzed by grey correlation method. The result shows that the grey correlations of intra-well distance

parent well producing time

average fluid volume of single cluster and natural fracture are higher. On this basis

the influence of intra-well position

parent well production time and average fluid volume to intra-well frac hit extent has been evaluated to obtain the following results. Firstly

the main intra-well position of frac hit is parallel

while the secondary is the position of opposite and malposition. Secondly

as the producing time of parent wells increase

the impact of frac hit significantly increases. The suggested optimal operation time of child wells is within 300 produce days of parent wells. Thirdly

as the average fluid volume of single cluster of child wells increases

the impact of frac hit increases too

so that it is suggested to optimize the liquid scale of single cluster according to the production time of parent wells and intra-well position. Lastly

the fluids volume

perforations and slurry rate should be strictly optimized in the section with cut-through natural fracture in order to reduce frac hit risk. Field tests show that the result can provide a reference to reduce the impact of intra-well frac hit of shale gas.