济阳坳陷古近系成岩作用及其对储层质量的影响?

大量的储层分析化验资料研究表明，济阳坳陷古近系砂岩储层经历了压实、胶结等多种成岩作用。压实作用以机械压实为主，压溶作用较少。胶结作用主要有十分普遍的石英次生加大胶结、碳酸盐胶结、粘土矿物胶结。碳酸盐胶结物有早、晚两期，早期泥晶方解石主要分布在浅层，连晶方解石充填的深度分布范围大，中深部最为发育。溶蚀作用主要有碳酸盐胶结物、长石颗粒和少量岩屑溶蚀。储层孔隙经历了由原生到次生的演化过程，在成岩演化过程中，长石的溶蚀作用、碳酸盐矿物的沉淀与溶解作用是影响孔隙大小的关键因素，早期方解石的胶结有利于后期次生孔隙的发育。不同凹陷次生孔隙发育的深度不同。在济阳坳陷西部的惠民凹陷次生孔隙主要发育于1500-2400m深度，向东至东营凹陷则主要发育于1650-2450m，再向东到沾化凹陷为2300-3500m，车镇凹陷为2200-2700m。从西向东、由南向北次生孔隙的发育深度逐步增大是受盆地沉积沉降中心的迁移规律控制的。

Paleogene diagenesis and its control on reservoir quality in Jiyang Depression

Analysis of lab data indicate that the Paleogene reservoir of Jiyang Depression experienced compaction, cementation and other diagenesis. The compaction is dominated by the mechanical compaction with compaction-dissolution being of little significance. The cementation includes quartz growth, carbonate-cementation and clay mineral-cementation. The carbonate cements can be divided into two different stages, the early microcrystalline calcite is mainly concentrated in the shallow strata, while the crystalline calcite is largely distributed within the middle-deep strata. The dissolution includes cabonate cements dissolution, lithic grains dissolution and detrital feldspar dissolution. The reservoir pore evolution changed from primary to secondary pores. The pore space was affected by the dissolution of calcite and feldspar, as well as the precipitation and cementation of carbonates. The cementation by early calcite is favorable for the the development of secondary pores in the late stage. Secondary pores in different sags show different developing depths. From west to east in the Jiyang Depression, the depths for the development of secondary pores developing show an increasing tendency, i.e.at 1 500-2400 m in the western Huimin Sag, 1 650-2 450 m in the central Dongying Sag, 2 200- 2 700 m in the Chezhen Sag and 2 300 - 3 500 m in the Zhanhua Sag. The characteristics of secondary pore distribution are controlled by the migration regularity of the depocenter and subsidence center of the basin.