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方法 在轮古 6井四开钻井完井液中加入不同浓度的表面活性剂ABSN ,选用轮古 1井奥陶系不同渗透率的天然和人造裂缝性碳酸盐岩心 ,通过改变岩心的初始水饱和度 (Swi) ,对水锁效应发生前后岩心渗透率的损害情况进行评价 ,同时对不同ABSN浓度条件下钻井完井液滤液的表面张力和油、水界面张力进行测定。目的 研究轮南古潜山碳酸盐岩裂缝性油气藏的水锁效应及其影响因素。结果 水锁效应与初始水饱和度及岩心的绝对渗透率有关 ,在钻井完井液中加入表面活性剂后 ,滤液的表面张力和油、水界面张力显著减小 ,水锁效应降低。结论 轮南古潜山碳酸盐岩油气藏水锁效应严重 ;初始水饱和度越低 ,岩心的绝对渗透率越小 ,水锁效应越严重 ;加入表面活性剂是减小水锁效应的有效途径 ,同时表面活性剂的加入对钻井完井液的性能影响不大
Methods Surfactant ABSN with different concentrations was added into the four open drilling and completion fluids of the Lungu 6 well. Natural and artificial fractured carbonate cores with different permeability of Ordovician in the Ordovician from the Ordovician of Well Gugu 1 were selected. By changing the initial water saturation (Swi) was used to evaluate the damage of core permeability before and after water lock effect. The surface tension and the interfacial tension of oil and water under different ABSN concentrations were also measured. Aim To study the water lock effect and its influencing factors of carbonate fractured reservoirs in Lunnan buried hill. Results The water lock effect was related to the initial water saturation and the absolute permeability of the core. After the surfactant was added to the well completion fluid, the surface tension of the filtrate and the interfacial tension of oil and water decreased significantly, and the water lock effect decreased. Conclusions The water lock effect of the Lunnan buried hill carbonate reservoir is serious. The lower the initial water saturation, the smaller the absolute permeability of the core, the more serious the water lock effect. The addition of the surfactant can effectively reduce the water lock effect Route, meanwhile the addition of surfactant has little effect on the performance of drilling and completion fluids