Evaluation of polymer flooding in sand conglomerate reservoir and discussion of its mechanism——by taking Nantun formation, Bei block 301, Huhe Nuoren oilfield as an example

Glutenite reservoirs are usually characterized by complex pore structure and strong heterogeneity.During the period of high water cut, the contradiction between layers and planes is becoming more prominent.Conventional technical measures are difficult to control the water cut rising rate of main reservoirs and cannot improve the utilization degree of poor reservoirs, which leads to the deterioration of oilfield development effect.Therefore, the high-water-cut oil reservoir of Nantun formation in Bei 301 block of Huhe Nuoren oilfield is taken as the main research object to optimize the design of polymer flooding test and carry out a 3-year field test of polymer flooding. The results show the comprehensive water cut of the test reservoir decreases by more than 10.0%, the natural decline is less than 5.0% for three consecutive years, and the stage oil increase reaches3.75×104 t. Compared with water flooding, the stage oil recovery increases by more than 8.5%, and the field test of polymer flooding has achieved good oil increase and precipitation development effect.