Abstract: The multi-fracturing horizontal well with tighter clusters is an effective means of developing shale oil reservoirs. Fracture spacing and well spacing are key parameters in the tight cluster hydraulic fracturing design. A discrete fracture network numerical model based on Comsol software is established, simulating multi-fractured reservoir with tighter clusters. The effects of fracture spacing, well spacing and fracture complexity on the stimulation effectiveness are discussed. The results show that, for the target reservoir, the cumulative production of a single well can increase to about 1.63 times by decreasing fracture spacing from 30 m to 10 m. The cumulative production of the target reservoir can increase about 51.17% by decreasing the well spacing from 400 m to 200 m. The 90 d cumulative production of a single well with complex fracture is 39.80% higher than that with simple rectangular fracture. Tight cluster hydraulic fracturing field experiments show that artificial fractures have non-uniform filling characteristics. Fractures characterized by equivalent refining methods can't reflect such characteristics. Therefore, the effects of the remote unpropped fracture on the stimulation effectiveness are also discussed. The effects of the remote unpropped fracture on the annual cumulative production of a single is about 4.38%. Field experiment shows that the multi-fractured horizontal well with tighter clusters could improve the single well production effectively by 79.70%.

Key words: shale oil reservoir, multi-fracturing, productivity analysis, hydraulic fracture, non-uniform filling