陆相页岩油储层水基钾-聚合醇钻井液抑制性实验研究

Experimental Study on Inhibition of Polyol Alcohol Drilling Fluid in Continental Shale Oil Reservoirs

我国南襄盆地泌阳凹陷拥有可观的页岩油经济储量。针对泌阳凹陷页岩4000 m以上浅储层的物性特点,开发出一种密度为1.15g·cm^(-3)的水基钾-聚合醇钻井液体系,钻井液配方为:清水+5%膨润土+4%KCl+4%聚乙二醇+0.3%NaOH+0.3%FA-367+0.8%KJ-3+0.4%SNH-1+0.03%PAM,并对其进行了室内实验评价。实验结果表明:该水基钾-聚合醇钻井液体系流变性较好,滤失量较低,有较强的泥页岩水化抑制性,能够长时间有效抑制近井壁地层中的黏土矿物和页岩微裂隙的水化膨胀。钻井液浸泡页岩的线膨胀率相较于清水浸泡的页岩显著降低,降低比例为25.15%。

Biyang sag in Nanxiang basin has good economic reserves of shale oil.According to the physical properties of shale reservoirs with depth of less than 4000 m in Biyang sag,a water-based potassium-complex alcohol drilling fluid with a density of 1.15 g·cm^(-3 )was developed.The drilling fluid formula was determined as follows:water+5%bentonite clay+4%KCl+4%polyethylene glycol+0.3%NaOH+0.3%FA-367+0.8%KJ-3+0.4%SNH-1+0.03%PAM.The experimental results show that the drilling fluid has appropriate rheology,low filtration loss,strong inhibition of mud shale hydration,and can effectively inhibit the hydration expansion of clay minerals and shale in the near-wellbore formation for a long time.The linear expansion rate of shale soaked in drilling fluid is significantly lower than that soaked in clear water,and the final reduction rate is about 25.15%.