松辽盆地东南部伏龙泉地区登娄库组致密储层特征及优质储层主控因素分析

Analysis of tight reservoirs characteristics and main control factors of high-quality reservoirs in Denglouku Formation in Fulongquan area,southeastern Songliao Basin

前人对松辽盆地东南部伏龙泉地区登娄库组致密储层的相关研究较为薄弱,制约了该区油气勘探开发工程部署。笔者采用岩矿鉴定、扫描电镜、矿物X射线衍射分析、常规压汞等技术,对其物性特征及优质储层主控因素进行详细研究。结果表明:致密砂岩碎屑颗粒组成总体特征为Q_(30.3)F_(34.3)R_(35.4),成分成熟度和结构成熟度均较低;储层以原生粒间孔和溶蚀孔隙为主;以低-特低孔、特低渗--致密为主,孔喉整体较细,主要为亚微米级和纳米级孔喉。综合常规压汞特征,致密储层分为Ⅰ类、Ⅱ类和Ⅲ类;优质储层主控因素主要包括有利岩性(粗粒碎屑岩和分选较好的细砂岩、粉砂岩),有利沉积微相(边滩、心滩和决口扇微相),有利微观孔隙结构(相对粗孔喉半径及高可动流体饱和度)。

Previous studies on tight reservoirs in Denglouku Formation in Fulongquan area,southeastern Songliao Basin,were relatively weak,which restricted the deployment of oil and gas exploration and development in this area.The authors use rock-mineral determination,scanning electron microscopy,mineral X-ray diffraction analysis,conventional mercury injection and other technologies to conduct a detailed study on its physical properties and the main control factors of high-quality reservoirs.The results show that the general characteristics of the clastic grain composition of tight sandstones are Q_(30.3)F_(34.3)R_(35.4),and both the compositional maturity and structural maturity are low.The reservoirs are dominated by primary intergranular pores and dissolution pores.The pore throat is mainly composed of low to ultra-low pores and ultra-low permeability and compactness.The pore throat is generally fine,mainly submicron and nanometer pore throat.According to the characteristics of conventional mercury injection,tight reservoirs are classified intoⅠ,ⅡandⅢtypes.The main controlling factors of high-quality reservoirs mainly include favorable lithology(coarse clastic rock and well sorted fine sandstone and siltstone),favorable sedimentary microfacies(marginal beach,central beach and crevasse fan microfacies)and favorable microscopic pore structure(relative coarse pore throat radius and high movable fluid saturation).