东海地区低渗透气藏普遍存在孔隙度低、渗透率低和束缚水饱和度高特点,加上滑脱效应、高速非线性流动等因素的影响,导致气—水两相渗流规律复杂多变,难以准确评估外来流体对产能的影响。针对这些问题,采用东海Y气田储层岩心和常用钻井液体系,开展了储层含水饱和度和钻井液侵入对气—水两相渗透性影响实验研究。结果表明,低渗透气藏中,30%为临界含水饱和度,超过该值后,气相渗透率下降速率显著加快,且临界值随岩心渗透率降低而减小;钻井液初期侵入速度较快,但在5 d后趋于稳定，适当增加返排压差,可有效减轻钻井液对储层伤害程度。研究结果为东海低渗透气藏高效开发方案制定提供了依据。

Low porosity, low permeability and high bound water saturation are common characteristics of low-permeability gas reservoirs in the East China Sea. Combined with the effects of slip phenomenon and high-speed nonlinear flow, these factors result in complex and variable gas-water two-phase permeability pattern, making it difficult to accurately evaluate the influence of foreign fluids on productivity. To address these issues, an experimental study on the influence of reservoir water saturation and drilling fluid invasion on gas-water two-phase permeability was carried out using the core from the Y gas field in the East China Sea and commonly used drilling fluid systems. The results show that the critical water saturation is approximately 30% in low-permeability gas reservoirs; beyond this value, the decline rate of gas-phase permeability accelerates significantly, and the critical saturation decreases with decreasing core permeability. The initial invasion rate of drilling fluid is relatively, but stabilizes after 5 days. Appropriately increasing the backflow pressure differential can effectively mitigate the damage caused by drilling fluid to the reservoir. This study provides a basis for formulating efficient development scheme for low-permeability gas reservoir in East China Sea.