延113—延133井区水平井钻遇地层特征及地质导向

Horizontal drilling formation characteristics and geosteering in Yan113-Yan133 well block

延113—延133井区山2^(3)储层以水平井开发为主,局部的构造隆起、厚度和倾角的变化都会造成水平井钻出储层。根据岩心和成像测井等数据,系统研究了山2^(3)砂体上覆、下伏和层间地层发育特征并依据地质认识指导水平井导向。研究表明砂体上覆地层一般发育水下天然堤砂泥岩薄互层沉积,当钻遇该类地层应及时降斜;下伏太原组泥岩有机质含量较高,呈现出高中子、高电阻率和低密度的特征,当钻遇地层岩性突变,泥岩电阻率200~300Ω·m,应及时增斜;层间发育少量泥质夹层和高伽马砂岩夹层,地质导向时可以微调或不调整,继续稳斜钻进。该研究成果对鄂尔多斯盆地山2^(3)储层水平井钻井有指导意义。

Permian Shan2^(3) reservoir in Yan113-Yan133 well block is mainly developed by horizontal wells.Regional uplift,thickness and dip changes will cause wells to drill out of Shan2^(3) reservoir.Based on core data and imaging logs this paper systematically studied the overlying,underlying and interbedded formation characteristics and guided horizontal wells geosteering by geological understanding.The results illustrated the overlying formation of Shan2^(3) sandbody develops thin interbedded sand and mudstone of underwater levee deposits and should build off in time.The underlying shale of Taiyuan Formation contains higher organic matter and shows high neutron,resistivity and low density in logs.Lithological mutation and 200~300Ω·m resistivity illustrate underlying formation and should build up timely.Shale interbeds and high gamma sandstone strips are developed which can fine tune or continue steady drilling.The research results have guiding significance for Shan2^(3) horizontal well drilling in Ordos Basin.