阿尔及利亚X区块泥盆系Siegenian组储层微观特征及成岩作用对其影响

Microcosmic Characteristics and the Effect of Diagenesis on the Siegenian Formation Reservoir of Devonian in X Block,Algeria

通过岩石薄片、铸体薄片、扫描电镜、压汞分析及粘土矿物X衍射分析等资料,从储层的岩性、成岩作用、孔隙类型及影响孔隙结构的因素方面,对阿尔及利亚三叠盆地泥盆系Siegenian组储层的微观特征及成岩作用对其影响进行了研究。研究结果表明,该储层以石英细砂岩、粉砂岩为主,成分成熟度高。储集空间主要有原生粒间孔、粒内溶孔、粒间溶孔、铸模孔、胶结物内溶孔及构造裂缝6种,主要以次生溶蚀孔隙为主,且首次在研究区发现了石英溶蚀孔,并研究了碱性流体的来源。孔隙结构以细孔、细喉-微喉型为主,少量中孔细喉型和微孔微喉型。成岩作用类型多样,在区内发现了碱性溶蚀作用。成岩作用对储层发育具有重要的影响,压实、胶结作用是导致孔隙度和渗透率降低的主要因素,溶蚀作用是区内储层改善的最重要的成岩作用类型。X区块勘探程度低,明确其储层微观特征有利于X区块的进一步勘探开发。

The microcosmic characteristics of the Siegenian Formation reservoir in X block are analyzed by studying the effect of lithology,diagenesis,pore types and clay minerals on pore structure based on cores,well-logs,and formation test data including the rock thin sections and cast thin sections,the observation of scanning electron microscopy,pressured-mercury testing and X-ray diffraction analysis of clay minerals.Reservoir lithology is mainly quartz fine sandstone with high compositional maturity.Six pore types including primary intergranular pores,intragranular dissolved pores,intergranular dissolved pores,moldic pores,cement dissolved pores and microfractures,are identified in the Siegenian Formation reservoir.The quartz intergranular dissolved pores and the quartz overgrowth cement dissolved pores are found for the first time in this area.The secondary dissolution pore is the main pore type in X block.Pore structure is mainly micro-pore with thin to micro-throat association,beside a few medium pores with thin throat and micro-pores with micro-throat.The diagenesis types are various.Compaction and cementation is the main reasons for the pores and pore throats decreasing.In the opposite,dissolution is important in improving the quality of reservoir.This study of the reservoir will guide the future exploration of this area.