Three-dimensional visualization experimental study on proppant transportation and placement in the Hi-way channel hydraulic fracturing technique

The pattern of placement of the proppant in the fracture determines the stimulation and success of the surgery. Using a three-dimensional visual parallel plate fracture model capable of simulating fracture height, length, and variable fracture width, we experimentally investigate the impact of fiber loading, fracture fluid viscosity, sand concentration, pulse time, perforation pattern, and injection rate on proppant transport, placement pattern, and access rate. Experimentally and visually, the migration process and the morphology of the proppant placement in the fracture were assessed. The formation laws of stable support columns and well-shaped high conductivity fracture channels in fractures have been elucidated. Experimental results show that increasing the fiber concentration improves the channel rate and the proppant mass is large and stable. The channel rate increases with the viscosity of the fracturing fluid, and it is difficult to form a perfect channel when the viscosity is small. If the constructive displacement is too slight or too large, it will not favor the formation of a Hi-way channel in the fracture. The optimal design displacement is 4.5 m(3)/min. When the proppant concentration is low, the passage rate is large, but the stability of proppant mass is poor under the scour of large displacement, the conductivity is low under the high closure pressure, the proppant concentration is too high, the suspension is difficult, the settlement rate is large, and it is difficult to form a large passage. The current column and the passage rate are larger for pulse times of 15-20 s. Cluster perforations are better than large continuous perforations. The higher the number of clusters in the same number of holes, the higher the channel rate. The formation laws of stable support pillars and well-shaped high conductivity fracture channels in fractures have been elucidated, which can be useful for efficient stimulation of oil and gas reservoirs.