Objective To address the issue of water block damage in unconventional oil and gas development and promote green development, this study developed a highly efficient composite clean water lock release system.

Method A bio-based surfactant, TMES, was synthesized using natural tung oil as the raw material and characterized through infrared spectroscopy, thermogravimetric analysis, and surface tension measurements. Simultaneously, a hydrophobic material, ZH-1, was successfully prepared using nano-SiO₂ as the raw material and vinyltriethoxysilane as the modifying agent, and its properties were characterized via infrared spectroscopy and wettability tests. Based on the criteria of enhancing rock surface hydrophobicity and reducing gas-water interfacial tension, an environmentally friendly composite water lock release system was optimized and designed, consisting of 10 wt% ZH-1 and 0.50 wt% TMES, and its comprehensive performance was evaluated.

Result Experimental results demonstrated that TMES exhibits excellent thermal stability and surface activity, while ZH-1 significantly increased the water contact angle from 27° to 115°. The environmentally friendly composite water block release system designed in this study successfully constructed a binary hydrophobic structure on the rock surface, elevating the water contact angle to 108.33°. Under a displacement pressure of 3 MPa, the system markedly reduced the water saturation of the rock to 13.27%, concurrently enhancing gas permeability and decreasing the water block damage rate to 13.19%.

Conclusion This study provides an environmentally friendly and highly efficient technical solution for mitigating water block damage in reservoirs.