摘要
断面紧闭程度是决定断层封闭与否的重要因素之一。在对断面正压力及泥岩涂抹分析的基础上,提出了断层紧闭指数的概念,将断层紧闭指数(IFT)定义为断面正压力σF与断裂带物质抗压强度σC之比。当IFT大于1时,断面紧闭,封闭性较好;反之,封闭性较差。对北三台北断裂封闭性的研究表明,IFT值沿断层的分布具非均一性,只要油层或紧邻其上地层处的IFT值大于1,就可垂向封闭油气,不要求油层之上各处的封闭性都好;同一时期内IFT的大小与深度没有必然的关系,深度大,并不表明IFT大和封闭性好,油气仍可能通过断层向上运移。
The degree of fault tightness is one of the important factors for fault sealing control.According to analyses of faulting stress and shale smearing,the fault tightness index(I FT )is defined as the ratio of faulting stressσ F to the compressive strengthσ C of fault zone.Where the value of I FT is bigger than1,the fault tightens and seals well;otherwise,it seals worse.The study shows that I FT values dis tributed along northern faulting in Beisantai field are of non-homogeneity.As long as the I FT is bigger than1in oil reservoir or its overlying stratum,the oil-gas in it could be vertically sealed in incompletely sealed conditions above the reservoir.In addition,the I FT values are not related to the buried depth during the same geological time,for the deeply buried fault couldn't mean the bigger I FT value and good sealing property,but the oil-gas in it still may migrate upward through the fault.
出处
《新疆石油地质》
CAS
CSCD
2003年第6期530-532,共3页
Xinjiang Petroleum Geology
