生物扰动构造对碎屑岩储层储集性能的影响

生物扰动可以改变碎屑岩储层的储集性能。对辽东湾盆地东营组下段和东濮凹陷沙四段储层储集性能的研究发现,辽东湾盆地东营组下段三角洲相泥质粉、细砂岩储层中,生物扰动构造发育,生物的觅食活动可使砂泥混合物中的泥质含量明显减少,储集性能变好;而东濮凹陷沙四段滨浅湖相粉砂岩和细砂岩的储层中,生物扰动提高了原始孔渗性,有利于成岩水的流动,是胶结物沉淀的良好环境,在油气生成运移之前,发生了早期胶结作用,经多次充填使孔渗性、含油性变差。未经扰动的部位,保持了相对较高的孔渗性,含油性较好。

THE EFFECT OF BIOTURBATE STRUCTURE ON THE PETROPHYSICAL PROPERTIES OF SANDSTONE RESERVOIR

Bioturbate structure can alter the petrophysical properties of sandstone reservoir. Bioturbate structures are abundant in the lower member of Dongying formation in Liaodong Bay Basin. The amount of clay and organic material of the reservoir was decreased by the activity of organisms ana the pstropbysicsl properties of the reservoir could be improved. With the enhancement of bioturbate structure, the porosity, permeability and oil saturation of the reservoir became higher. Before the migration of hydrocarbon, early calcite cementation developed in the reservoir of Es4 member of Dongpu depression, which was favored by the high original porosity and permeability. The calcite cement could worsen the petrophysical properties of this biotur-bated parts of the reservoir while clay retarded cementation in the non-biotur-bated parts and thas the porosity and permeability remained relatively high.