湖相碳酸盐岩致密油主控因素及“甜点”刻画

Main-Controlling Factors and “Sweet-Spot” Characterization of Lacustrine Carbonate Tight Oil Reservoir

针对辽河坳陷西部凹陷雷家地区沙四段湖相碳酸盐岩致密油勘探面临的主控因素认识不清,缺少致密油储层定量分类标准及适用于老油田的"甜点"刻画方法等问题,系统性开展岩心测试,研究了岩性、物性、孔喉、含油性、脆性、地应力与油层产能之间的关系。根据储层中油气赋存状态,岩性、物性、含油性及产能之间的关系,确定储层物性及含油性下限,建立了致密油分类标准,形成了一套利用测井资料刻画致密油"甜点"的研究方法。研究表明:岩性控制储集空间类型、物性、含油性,进而影响油层产能,是沙四段致密油的主控因素;杜家台油层Ⅰ类+Ⅱ类"甜点"区为27.2km^2,高升油层Ⅰ类+Ⅱ类"甜点"区为77.5km^2,新增三级储量近亿吨。该方法对老油田致密油评价具有借鉴意义。

The Sha-4 Member lacustrine carbonate tight oil exploration in the western depression Leijia of Liaohe Depression was challenged by unclear main-controlling factors,lack of quantitative tight oil reservoir classification standard and "sweet-spot"characterization method for old oilfield.The core test is used to systematically study the relationship between lithology,physical properties,pore-throat,oiliness,brittleness,geo-stress and reservoir produet ivity.The reservoir properties and lower limit of oiliness are determined according to the relationship between the hydrocarbon oecurronee,lithology,physical properties,oiliness and reservoir productivity.A classification standard for tight oil reservoir is established to characterize the "sweet-spot"through logging data.Research indicates that the lithology is considered as the main-controlling factor of Sha-4Member tight oil reservoir,which determines the reservoir type,physical properties,oiliness,and then influences the reservoir productivity.The "sweet -spot"area of the Class-Ⅰ and Class-Ⅱ reservoirs in Dujiatai is 27.2km^2,the "sweet-spot"area of the Class-Ⅰ and Class-Ⅱ reservoirs in Gaosheng is 77.5km^2,and the corresponding new three-level reserve is nearly 100million tons.This method could provide certain reference for the tight oil evaluation in old oilfields.