牛20和营11低渗透油藏“四敏”试验研究

Experiment research on “four sensitivities” in Niu 20 and Ying 11 low permeability reservoirs.

牛２０、营１１是胜利油田的两个特低渗开发块。为保护储层、进行合理开发，对两断块油藏的敏感性、粘土稳定剂与地层的配伍性进行了研究。两断块对水均表现出中等到弱的敏感性，牛２０断块岩心水敏系数基本上在０．３～１．０之间，而其中大多数在０．７～１．０之间，极少部分岩心的水敏系数大于１．０，营１１断块岩心水敏系数大于０．７；牛２０、营１１断块的临界盐度分别为１５０００ｍｇ／Ｌ和１２０００ｍｇ／Ｌ；用盐酸和土酸对两断块岩心进行处理后，渗透率只提高１％～１９％，无明显酸化效果，部分岩心还表现出一定的酸敏感性；牛２０断块临界流速为５．８７ｍ／ｄ。

Niu 20 and Ying 11 are two development blocks with extra low permeability in Shengli Oilfield. In order to protect reservoir and develop reasonably, sensitivity of these two fault blocks and compatibility of clay stabilizing agent and formation were studied. Both two fault blocks appear as middleweak water sensitivity. Core water sensitive coefficient of Niu 20 fault block distributes over 0.3-1.0. The bulk of the coefficient lies in 0.7-1.0, only a few is more than 1.0. Core water sensitive coefficient of Ying 11 fault block is more than 0.7. Their critical salt sensitivity are 15000mg/L and 12000mg/L respectively; After treatment of two fault block cores with hydrochloric acid and mud acid , permeability increases 1%-19% only, acidizing effect is not obvious, some cores appear as some acid sensitivity; critical velocity of Niu 20 fault block is 5.87m/d. 