东营凹陷古近系砂岩储集层特征对比

东营凹陷可分为北部陡坡带、中央隆起带和南部缓坡带，由于地质背景有差异，古近系砂岩储集层在不同地区的特征不同：北部陡坡带以近岸水下扇砂砾岩沉积为主，进入晚成岩期的时间早，深度浅，次生孔隙发育中等，主要分布在1650-2450m深度，3200-3500m深度存在第二次生孔隙带，碳酸盐溶蚀和胶结作用在垂向具有分带性；中央隆起带以浊积扇砂岩为主，但由于断裂发育，酸性水活跃，进入晚成岩期的时间也较早，次生孔隙最发育，又分布范围大，1800-3500m深度均发育次生孔隙，碳酸盐胶结弱，储集层物性最好；南部缓坡带以滨浅湖和三角洲沉积为主，进入晚成岩期的时间晚，次生孔隙发育少，北部和中部物性相对差。图4表1参31

Correlation of the Paleogene sandstone reservoirs in different areas of Dongying Sag

Dongying Sag is divided into the northern steep slope zone, the central uplift zone and the southern gentle slope zone. Because of their geological background differences, these reservoirs of the Paleogene have different characteristics. In the north, the reservoir rocks are mainly sandstones and conglomerates that entered the later diagenesis earlier at the shallower depth. The secondary pores developed moderately and are mainly distributed from 1650m to 2450m. In the interval of 3200 3500m exists another secondary pore zone. The dissolution and cementation of carbonates occurred alternatively in vertical profile. In the central uplift, the reservoir rocks are mainly turbidites, the faults developed well and acid water was active in the geological history. Therefore, the reservoirs entered the later diagenesis stage in the earlier time. In the uplift, the secondary pores developed best and widely spread from 1800m to 3500m. The carbonate cements are poor, and the reservoirs are the best in quality. In the south, the reservoir rocks are mainly shore shallow lacustrine sandstones and get into the later diagenesis lately. The secondary pores in the south developed poorly and the reservoir quality is relatively poor compared to those in the north and south zones.