阿尔及利亚A区块三叠系砂岩储层特征及其影响因素

RESERVOIR CHARACTERISTICS OF TRIASSIC SANDSTONE AND ITS INFLUENCING FACTORS,ALGERIA A BLOCK

三叠系砂岩储层是阿尔及利亚A区块最主要的勘探目的层,研究其储层特征及控制因素对区块内油气勘探及井位部署有着重要的指导意义。通过岩心观察,结合区域地质资料及样品实验室分析测试资料,认为阿尔及利亚A区块三叠系砂岩储层以中粒、细粒岩屑石英砂岩为主,成分成熟度高,结构成熟度中等,分选好,颗粒圆度为次棱角—次圆,发育有原生粒间孔、次生溶蚀粒间孔,孔喉组合类型以大孔-细喉道为主。受机械压实作用、化学压溶作用、胶结作用、溶蚀作用等成岩作用影响和沉积环境、构造作用控制,阿尔及利亚A区块三叠系砂岩储层属于低孔、特低孔-中低渗、特低渗储层。

Triassic Sandstone is the main target formation in Algeria A block.So,to study its reservoir characteristics and influencing factors is significant for both hydrocarbon exploration and wellsite deployment.Based on core observation,regional geology data analysis and sample experimental test,we consider that(1) Triassic Sandstone is mainly composed of middle-to fine-grained lithic quartz sandstone with a high compositional maturity and a middle texture maturity;(2) it is well-sorted and its particle is of both subangular and subcircular roundness;(3) primary intergranular pore and secondary dissolved intergranular pore are developed in Triassic Sandstone with a type of large pore and fine throat as the soul;(4) it is affected by diagenesis of mechanical compaction,chemical pressure solution,cementation and dissolution,meanwhile it's controlled by sedimentary environment and tectonism;and(5) Triassic Sandstone is one reservoir with low porosity,extra low porosity and middle to low permeability,extra low permeability.