Sensitivity analysis of transitional zone reservoirs in the Sazhong area of Daqing oilfield

In order to effectively develop the reservoir in the “Sazhong” transitional zone, indoor experiments were conducted to study the sensitivity of the reservoir to velocity, water content, acidity, alkalinity and salinity. The results indicate that the reservoir in this area has weak sensitivity to velocity, water content, and alkalinity, it shows no sensitivity to acidity and medium sensitivity to salinity. Increasing the water injection rate leads to an increase in core permeability without causing blockage phenomena such as “bridge plug” or “cake plug”, indicating that the unstable solid particle content in the reservoir of Daqing Oilfield after long-term water injection development is extremely low, which will not cause reservoir blockage. Boosting well production can be achieved through actions like raising the water injection rate and acidizing. Additionally, it was observed that while the bottom of PI formation is not sensitive to alkalinity in the transitional zone, PII formation exhibits weak sensitivity.