The polymer is easily trapped in the gap between the proppant particles

so the conventional hydraulic fracturing technology of the uniform sand production has limitation for the transformation of the low permeability

ultra-low permeability and shale gas reservoirs. The channel hydraulic fracturing technology can effectively increase the oil and gas production by forming a high diversion channel by non-uniform sand deposition. The effects of channel fracturing technique are mainly determined by the channel size of the formed sand embankment. By the similarity criterion

we established the experimental method of visual simulation system of

channel fracturing to systematically analyzed the influence of the fracturing fluid viscosity

proppant concentration

fiber addition

pore arrangement

pulse time and construction displacement on the proppant placement pattern and channel ratio. Then we used the methods of the partial least squares regression and the importance of variable projection to analyze the influence degree of various factors on the channel rate. Under the experimental conditions

it is indicated that when the injecting volume is 4 ~ 6 m

3

/min and the viscosity of fracturing fluid is 150 ~ 250 mPa·s

the concentration of proppant is lower

the concentration of fiber is higher

the pulse time is shorter

the perforation methods is more

and the higher viscosity is better. By means of partial least squares regression

importance analysis of variable projection

and Pearson product-moment correlation coefficient

the influence degree of each channel rate is in a descending order as: viscosity of fracturing fluid perforation methods pulse time concentration of fracturing proppant concentration of fiber injecting volume.