Geological characteristics and sensitivity damage analysis of MB2 reservoir

This study assesses the sensitivity of the low-permeability reservoir in the MB2 block of the MB oilfield through an analysis of its development features, geological properties, thermal and pressure regimes, fluid characteristics, and clay mineral composition. This research thoroughly examines and explains the primary factors contributing to the high-pressure under-injection phenomenon in the MB2 block. The research reveals that the primary cause of elevated injection pressure in the reservoir rock is its significant water sensitivity. This sensitivity leads to the swelling and dispersion of clay minerals during water injection, resulting in pore blockage. At the same time, due to the small throat of the pores, the fluid flow resistance is large during the flow process, and the fluid is difficult to flow into the deep part of the formation. This study has preliminarily identified the key geological factors contributing to the high-pressure under-injection in the MB2 reservoir.