钻井液与完井液2023，Vol.40Issue(6)：815-826,12.DOI:10.12358/j.issn.1001-5620.2023.06.017
致密油储层超低界面张力乳化体系强化渗吸效果及机理研究
Study on the Imbibition Law and Mechanism of Strong Emulsification System Based on the Experimental and Numerical Assessment
摘要
Abstract
Surfactants are usually added to the fracturing fluids to enhance the imbibition between fractures and matrix,which is an important measure to improve oil recovery.The popular perspective believes that altering water-wet conditions and keeping a relatively high IFT value are the keys to achieving the imbibition process.Recently,both indoor experiments and oilfield practice have shown that the surfactant systems with ultra-low IFT can also achieve imbibition and effectively recover oil from the matrix.For the problem that the imbibition mechanism of ultra-low IFT system is still unclear,the wettability alteration system,ultra-low IFT system,and emulsification system are constructed,the characteristics of imbibition systems and imbibition recovery are clarified,the oil-water transport patterns and dominant mechanisms of wettability alteration system and ultra-low IFT system with excellent emulsification are revealed by using mathematical models.The results show that the applicability range of the wettability alteration system and ultra-low IFT system with excellent emulsification is different.The wettability alteration system has better imbibition effects under 0.1 mD,but the ultra-low IFT system with excellent emulsification performs better under 0.01 mD and 0.001 mD.The imbibition process of the wettability alteration system is a layer flow pattern dominated by capillary force,the rate at which the wetted phase fills the pores decreases rapidly with the decrease of permeability,and the imbibition recovery decreases significantly from about 45%to 18%.The micro-nano emulsions can be formed by the ultra-low IFT system with excellent emulsification,which has a special emulsification and diffusion mechanism.In the early stage,oil is mainly recovered by emulsification and diffusion,in the late stage,the layer flow pattern of IFT reduction and wettability alteration gradually works,and the imbibition recovery decreases from about 38%to 23%.The emulsification and diffusion mechanism of the ultra-low IFT system with excellent emulsification is suitable for the imbibition of tighter reservoirs,and has a broad application in fracturing and stimulation of tight reservoirs.关键词
自发渗吸/超低IFT/乳化/核磁共振/致密储层Key words
Spontaneous imbibition/Ultra-low IFT/Emulsification/NMR/Tight reservoirs分类
能源科技引用本文复制引用
侯小雨,周福建,姚二冬,王秀坤..致密油储层超低界面张力乳化体系强化渗吸效果及机理研究[J].钻井液与完井液,2023,40(6):815-826,12.基金项目
国家自然科学基金"纳米乳液在致密砂岩储层中的吸附特性及其解水锁机制研究"(52004306) （52004306）
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中国石油天然气集团有限公司-中国石油大学(北京)战略合作科技专项"鄂尔多斯盆地致密油-页岩油富集、高效开发理论与关键技术研究"(ZLZX2020-02) （北京）
国家科技重大专项"中亚和中东地区复杂碳酸盐岩油气藏采油采气关键技术研究与应用"(2016ZX05030005) （2016ZX05030005）
国家重大科技专项"超深裂缝性气藏井筒失稳机理及转向工艺优化研究"(2016ZX05051003)资助. （2016ZX05051003）
