塔河油田奥陶系岩溶型碳酸盐岩油藏储集空间发育特征及地质模式探讨

碳酸盐岩表生岩溶作用控制着塔河油田奥陶系油藏缝洞系统的发育及分布。塔河油田奥陶系油藏经历了加里东期和海西早期两次岩溶作用，造成了储层极强的非均质性。通过塔河油田岩溶作用演化及发育期次的研究，将塔河油田奥陶系垂向岩溶带划分为地表岩溶带、纵向渗滤岩溶带和水平潜流岩溶带，平面上发育岩溶高地、岩溶斜坡和岩溶洼地3个地貌单元。通过对野外露头、岩心、钻井、测井、地震及生产动态资料的综合研究，认为溶洞、溶蚀裂缝及蜂窝状孔洞等连续孔隙是该区有效储集空间，基质作为不渗透（低渗）层对缝洞系统有一定的隔挡作用。结合表生岩溶洞穴的原理及对孔隙状态的控制作用，将塔河油田溶洞储集体根据不同成因分为落水洞、潜流洞和小溶洞，按溶洞充填物类型分为垮塌充填洞、机械充填洞和化学充填洞，同时建立了不同类型孔洞系统的识别特征及地质模式。结合塔河油田洞穴储层发育特征及生产实际，最终建立了塔河油田岩溶储集空间展布模式。

Development Characteristics and Geological Model of Ordovician Karst Carbonate Reservoir Space in Tahe Oilfield

The carbonate epigenic karstification controls the development and distribution of fracture-cave system in the Ordovician reservoir of Tahe Oilfield.Ordovician reservoir of Tahe Oilfield has experienced two periods of karstification in the Caledonian and Early Hercynian,composing a highly heterogeneous reservoir.Based on the karst origin,evolution and growth mechanism of Tahe Oilfield,the Ordovician reservoir was vertically divided into surface karst zone,vertical percolation karst zone and horizontal subsurface flow karst zone,as well as three karst paleotopography units as highlands,slopes and depressions horizontally.In this paper,outcrop observations,cores,drilling,well logging,seismic and production performance are used to affirm that karst cavities,dissolved fractures and honeycomb cavities are effective reservoir space in the region,and the matrix as the impermeable layer can block the fracture-cave system to a certain extent.Combined with the epigenic karstification theory and the influences on reservoir space,the reservoir space of the Tahe Oilfield are divided into sinkhole,undercurrent cavity and small cave according to their different causes,and the cavities can also be divided into collapse filling cavty,mechanical filling cavity and chemical filling cavity according to the filling patterns.Meanwhile,the geological model of different types of pore-cave systems was built up.Taking advantage of the development characteristics of the carbonate reservoir of Tahe Oilfield and production practice,the Tahe Oilfield karst reservoir space distribution model was eventually built up.