Secondary and tertiary enhanced oil recovery address the issue of reduced oil production over the years. To facilitate the recovery of residual oil in the reservoir, well stimulation using strong acids, e.g. concentrated HCl, is usually used to enlarge the pores trapping oils in the formation. However, the application of strong acids suffers from short penetration depth as a result of fast reaction with the rock (e.g. carbonate) formation. Herein we describe two new approaches, in which encapsulated and polymerized acid precursors are used to deliver both acids and surfactants in a controlled manner for more efficient enhanced oil recovery. In comparison with the common industry methods, our methods allow for controlled acid release so that deeper acid penetration can be achieved. Meanwhile, the acid can then act as surfactant after dissolving rock, which helps to free the residual oil in the reservoir.