Conformance control study by micrometer sized dispersed particle gel in three-dimensional tight oil fracture network

With the increasing demand for petroleum resources, the efficient development of unconventional resources is of great significance, such as tight oil. Hydraulic fracturing is necessary for the production of tight oil. However, it aggravates the reservoir heterogeneity with fracture network. With better fluid conformance control in the fractures, heterogeneity in tight oil reservoir will be improved. The high production period can be extended. In this study, the fracture equivalent width of the fracture network model was calculated with conversion coefficient R as 0.52ⅹ106, 4.04ⅹ106 and 4.54ⅹ106 for the two, four and six turning points fracture network models, respectively. A dispersed particle gel (DPG) was used to control fluid mobility in tight oil fracture network model. The median particle size of this fluid is 3.17 μm and viscosity is 2.85 mPa s. In this study, it shows a better conformance control effect at a flow rate of 0.5 mL/min, with matching coefficient between DPG diameter and fracture equivalent width is 0.6. It is found that when the matching coefficient is less than 0.6, DPG can form unstable multi-layer stacking, and stable double-layer bridge stacking in the fracture when matching coefficient is 0.6. It would be single layer retention when it is greater than 0.6. With matching coefficient of 0.6, the conformance control rate would be 72.6% at flow rate 0.5 mL/min. This study would contribute to recovery the tight oil reservoir through heterogeneity remedy with conformance control in fracture network. •The particle size range is mainly concentrated in 2–5 μm.•When f is 0.6 and Q is 0.5 mL/min, the Fr and Frr are the largest.•The DPG exists in fracture through surface retention, coalescence and accumulation.•With f of 0.6 and Q less than 0.5 mL/min, the mobility control effect is better.•The more complex the fracture network, the better the mobility control effect.