合肥盆地周缘石炭—二叠系碎屑岩储层特征及盆内储集性预测

Peripheral Reservoir Characteristics and Prediction of Intrabasinal Reservoir Properties of Carboniferous-Permian Clastic Rock in Hefei Basin

合肥盆地周缘石炭系—二叠系碎屑岩的成分成熟度和结构成熟度较高,成岩后生作用强烈,特别是强的机械压实作用和成岩自生矿物的多期胶结作用,使其孔隙结构和储集物性变差。盆地南缘石炭系碎屑岩成岩强度更强,孔隙结构更差。碎屑岩的孔隙类型多样,以构造裂隙和次生孔隙为主,且裂隙和次生孔隙的形成呈多期性,先期形成的次生孔隙不同程度地被后期的自生矿物充填。结合区域地质特征、烃源岩热演化特征和地球物理特征认为盆地内与周缘相对应的石炭系—二叠系碎屑岩储集性能可能变好,特别是肥中断裂以北地区及印支面附近可能存在裂隙和次生孔隙为主要储集空间的良好的储集层。

Compositional Maturity and textural maturity of Carboniferous- Permian clastic rock in periphery of Hefei Basin is rather high, but the strong diagenetic epigenesis,especially strong me- chanical compaction and diagenetic authigenic mineral multi- stage cementation resulted in pore texture and reservoir prop- erties getting poorer.The diagenetic grade of Carboniferous clastic rock in the southern margin of the basin is higher so that the pore texture is even poorer.Though the porosity types of the clastic rock are various the dominant porosity formed in multi-stage is the structural fissures and secondary porosity. The early formed secondary porosity was more or less filled with later formed authigenic mineral.Comprehensively analyz- ing regional geology,source rock thermal evolution and geo- physical characteristics,it is considered that intrabasinal clas- tic rock reservoir properties of Carboniferous-Permian are get- ting better than the peripheral one.In northern part of Feizhong fault and near the Indosinian plane,it is possible to find out the better reservoir whose predominant reservoir space is fissures and secondary porosity.