东营凹陷现河地区沙三段下亚段储层成岩作用

Diagenesis of the low third member of the Shahejie Formation in Xian-he area of Dongying Depression

东营凹陷现河地区沙三段下亚段发育湖泊相、三角洲相和浊积扇相等成因类型的砂体,地层埋藏深度变化大,成岩作用复杂。通过钻井取心、岩石薄片和扫描电镜观察等手段,研究了该区成岩作用。研究结果表明,压实作用、胶结作用、交代作用以及多期次的溶解作用是储层的主要成岩作用。其中,压实作用和胶结作用使储层原始孔隙损失较大。自晚成岩A期到晚成岩B期,因有机质成熟过程、粘土矿物转化、烃类与硫酸盐矿物的热化学氧化还原反应等造成的酸性地层水介质,使次生孔隙发育。

Many genetic types of sandbodies of the facies of lake,delta and turbidite fan developed in low third member of the Shahejie Formation in Xianhe area of Dongying Depression.Diagenesis is ver-y complex because of the deep buried depth.Based on the measurements of drilling,coring,core wafer and scanning electron microscope,the diagenesis is researched in the studied area.The results indicate that compaction,cementation,metasomatism and multi-period-times dissolution were the main diageneses of the reservoirs.In all of them,the compaction and cementation are the main factors to decreasing stratum porosity and permeability.From late diagenesis A period to late diagenesis B period,acid formation water makes the secondary pores develop,which was caused by the organic matter maturation,clay minerals transformation and thermo-chemistry oxidation deoxidation reactions between hydrocarbon and sulphate minerals.