玉北地区中下奥陶统储层主控因素分析

玉北地区奥陶系鹰山组和蓬莱坝组作为主要储层,发育有裂缝型、裂缝-孔洞型和孔洞型3类储层,在空间展布上具有＂东西分异、上下分层＂特征。在岩心观察、成像测井、薄片及物性等资料分析基础上,结合扫描电镜、碳氧同位素测定结果,深入探讨玉北地区中下奥陶统储层的主控因素,结果表明：断裂、裂缝作为重要的疏导体系促进地层内幕岩溶储层发育,古地貌控制岩溶储层发育的有利相带,东西差异的断裂活动和岩溶相带分布决定了区域上东西分异的储层特征;原岩性质对鹰山组上下段发育不同储层类型起到了关键性作用,深部热液活动在早期基底断裂的疏导作用下对蓬莱坝组储层起到了良好的改造作用;原岩性质和热液活动的共同作用致使奥陶系储层出现上下分层的特征。最后综合多种储层受控因素,对玉北地区中下奥陶统储层发育模式进行探讨。

Analysis on main control factors of Middle-Lower Ordovician reservoir in Yubei Area

Yingshan Formation and Penglaiba Formation of Ordovician are the main reservoirs in Yubei Area,developing three reservoir types,such as the fracture,fracture-pore and pore type reservoirs.There are the characteristics of east-west differentiation and upper and lower zoning in space distribution.Based on the data of core observation,imaging logging,identification of thin section and physical properties,and combined with SEM and the results of isotope geochemistry of carbon and oxygen,this paper analyzes the main control factors of Middle-Lower Ordovician reservoir in Yubei Area.The results show that fracture and crack as the important guidance system promote the development of karst reservoir in the insider formation.Paleogeomorphology controls the favorable facies belt of karst reservoir.The different fault activities and distribution of karst facies belt in the east-west part determine the reservoir characteristic which is east-west differentiation.Protolith nature plays a decisive role in different reservoir types of upper and Lower Member of Yingshan Formation.The deep hydrothermal activity plays a good role in the transformation of Penglaiba Formation reservoir under the guidance function of the early basement faults.Ordovician reservoirs appear to be upper and lower zoning by the combined action of protolith nature and hydrothermal activity.At last,the various controlling factors of reservoir are synthesized and the development mode of Middle-Lower Ordovician reservoir is discussed.