Conventional packers are not reliable when they are set in big hole and irregular open hole . In this regard ,the technology of water-swellable packer was studied .By testing the swelling rate and seal-ing capability of water-swellable rubber ,an optimum formula of the special rubber was selected ,namely , rubber D1 + 70% water absorbing polymer + 20% reinforcing-agent A + 40% reinforcing-agent C .The in-fluences of temperature and salt solution on water-swellable rubber was analyzed in laboratory tests ,indica-ted that the swelling rate went up with the temperature ,but declined when the temperature was over 120℃ ,and the swelling rate decreased as the ion-strength of salt solution increased .Moreover ,the sealing mechanism of the water-swellable packer was investigated ,and the isolation behavior of such packer was analyzed by finite element method depending on swelling rate .It showed that the isolation capability was higher when the swelling rate of rubber element increases .Field applications showed that the water-swellable packer no longer has poor reliability that conventional packers have when they were set in big hole and irregular open hole .%针对常规封隔器在大尺寸及不规则井眼中使用可靠性较差的问题，开展了遇水膨胀封隔器技术研究。采用了测试遇水膨胀橡胶膨胀率和封隔能力等的方法，优选了遇水膨胀橡胶的配方：橡胶 D1＋70％吸水聚合物＋20％补强剂 A ＋40％补强剂 C 。通过室内试验分析了温度及盐溶液对遇水膨胀橡胶的影响规律，结果表明：随着温度的升高，遇水膨胀橡胶的膨胀率增大，但当温度高于120℃时，其膨胀率随温度升高而降低；盐溶液的离子强度越高，遇水膨胀橡胶的膨胀率越低。分析了遇水膨胀封隔器的膨胀密封机理，并采用有限元方法分析了遇水膨胀橡胶不同膨胀率下的封隔能力，发现遇水膨胀橡胶的膨胀率越大，封隔能力越强。现场应用表明，遇水膨胀封隔器能解决常规封隔器在大尺寸及不规则井眼中使用可靠性较差的问题。
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