东庄复杂断块油田油层分布规律研究

东庄油田位于南阳凹陷西南部,是在背斜构造背景上被一组与背斜长轴走向一致的南倾正断层切割的复杂断块油田;储层主要为北西方向沙堰三角洲前缘砂体,孔隙度14％～15％,渗透率(10.5～28.0)×10~(-3)μm~2;该背斜为凹中之隆,油源充足,背斜控制油气富集的范围,砂体决定油气富集程度,断层起油气再分配和遮挡作用;油层深度2 210～2 700m,含油井段约500 m,含油层数3～5层,单井厚度10～20 m;背斜北翼断块含油高度60～150 m,含油面积0.5～0.8km~2;南翼断块含油高度30～100 m,含油范围较小。根据对东庄油田的地质认识,钻评价井4口,落实含油面积4.9km~2,探明石油地质储量259×10~4t。

Distribution Pattern of Pay Zones in the Complex Dong- zhuang Fault Block Oilfield

Dongzhuang oilfield, located in the southwest of Nanyang depression, is a complex fault block oilfield that developed in an anticlinal setting and was cut by a group of south - dipping formal faults with trends parallel with the long axis of the anticline. The reservoirs with porosity of 14%-15% and permeability of (10. 5-28. 0) + 10-3 tan are mainly frontal sandbodies of the Shayan delta in the northwest direction. This anticline is a swell in the depressed area and has adequate source rocks. It controls the area of hydrocarbon enrichment and the sandbodies control the degree of hydrocarbon enrichment, while the faults function as channels for hydrocarbon redistribution and as sealing. The pay zones are 2,210 m to 2,700 m deep; the oil- bearing interval is about 500m thick; the number of pay zones is 3 to 5; and the averaged single layer thickness is 10 m to 20 m. The fault block in the northern limb of the anticline has a hydrocarbon column of 60 m to 150 m high and an oil - bearing area of 0. 5-0. 8km2, while that in the southern limb has a relatively small oil - bearing area. Based on the geological knowledge of Dongzhuang oilfield, 4 appraisal wells are drilled to materialize an oil - bearing area of 4. 9 km2 and proved geological reserves of 2. 59 million tons.