多种方法评价断层封闭性——以金湖凹陷石港断裂带为例

Assessment of fault sealing ability: An example from the Shigang fault zone in the Jinhu depression, northern Jiangsu

关键词:  石港断裂带  断层封闭性  断层活动强度  现今应力方向  模糊综合评判

Key words:  Shigang fault zone  fault sealing ability  faulting intensity  orientation of the present-day stress  fuzzy comprehensive judgement

摘要:

运用断层活动强度、现今应力作用方向与断层封闭效应及模糊综合评判方法,对金湖凹陷石港断裂带地区的断层封闭性进行了评价。研究表明,石港主控断层在不同位置的封闭性存在很大的差异,具有"南开北闭"特征,表现为断层在南部开启,在北部闭合,从而有效地封闭了油气。北部的次级派生断层封闭性较好,在局部形成断层遮挡油气藏。通过模糊综合评判法评价断层封闭性,认识到不同时期各断层封闭成藏情况不同:阜宁组断层封闭性好于戴南组;阜四段主要为泥岩,封闭性最好;阜二段和戴一段封闭性较好。分析结果与实际勘探状况相吻合。

Abstract:

The assessment of fault sealing ability of the Shigang fault zone in the Jinhu depression, northern Jiangsu is based on the faulting intensity, the orientation of the present-day crustal stress, fault sealing effects and fuzzy comprehensive judgment technique. There are greater differences in the fault sealing ability in different parts of the Shigang fault zone:generally open in the southern part and close in the northern part, which may be valid for the sealing of oil and gas. In the northern part, the secondary induced faults have better sealing ability, and may be considered as the barriers of oil and gas. Moreover, there are also differences in the fault sealing ability in different periods. The fault sealing ability in the Funing Formation is generally better than that in the Dainan Formation, especially best in the fourth member composed of mudstones of the Funing Formation, and better in the second member of the Funing Formation and the first member of the Dainan Formation.