苏仁诺尔断裂遗留渗漏通道垂向封闭形成时期及研究意义

Vertical sealing formation period of water leakage path remained by Surennuoer fault and its research significance

为了研究苏仁诺尔断裂遗留渗漏通道垂向封闭性形成时期,对其静止后遗留的渗漏通道类型及特征进行了研究,认为断裂停止活动后主要存在未完全闭合的倾斜裂缝、垂直裂缝和破碎带3种渗漏通道。在断裂遗留渗漏通道封闭机理分析的基础上,研究其垂向封闭性形成时期确定方法得到:可通过裂缝面压力等于泥岩塑性极限时期确定未完全闭合倾斜裂缝垂向封闭性形成时期;可通过SiO2和CaCO3形成第一个沉淀带时期确定垂直裂缝垂向封闭性形成时期;可利用油气通过断裂渗滤运移速度等于零或SiO2和CaCO3形成第一个沉淀带时期确定破碎带垂向封闭性形成时期。通过苏仁诺尔断裂不同遗留渗漏通道垂向封闭性形成时期与南一段源岩大量排烃期关系得到,未完全闭合倾斜裂缝和破碎带在青元岗组沉积时期断裂停止活动后马上形成垂向封闭,早于南一段源岩的大量排烃期,有利于油气在南二段聚集与保存。苏仁诺尔断裂西南部和东北部垂直裂缝分别于古近纪早期、新近世末期—现今形成垂向封闭性,均晚于南一段源岩大量排烃期,不利于油气在南二段中的聚集与保存。

In order to research ou the vertical sealing formation period of water leakage path remained by Surenuoer fault, the types and characteristics of water leakage path remained by the rest of the fault are studied. It is believed that after the ceasing of fault activity, the water leakage paths existed mainly include dipping fracture without fully closed, vertical fracture and broken belt. Based on the analysis of the sealing mechanisms for water leakage path remained by fault, the nlethod to determine the vertical closure property period is studied. According to the study, the vertical closure property formation period for dipping fracture without fully closed can be determined through fracture face pressure being equal to mudstone plastic limit, that for vertical fracture can be determined through the first deposition belt formation period for SiO2 and CaCO3 , and that for broken belt can be determined through o filtering migration velocity for hydrocarbon passing faults or the first deposition belt formation period for SiO2 and CaCO3. According to the relationship between different vertieal closure property formation periods of water leakage path remained by Surennuoer fault and the expulsion period of large quantity of hydrocarbon in Nanl source rock, it is obtained that for dipping fracture without fully closed and the broken belt the vertical closure has been formed immediately after the fault was not active in the depositional period of Qingyuangang Formation. The closure property forms earlier than the expulsion period of large quantity of hydrocarbon for Nanl source rock, and it is favorahle for hydrocarbon accumulation and conservation in Nan2 Member. The vertical closure property for the vertical fractures in the southwest part and that in the northeast part of Surennuoer faulthave been formed at early palaeo - modern times and end of late modern times - present, and both the closure property formation periods are later than large quantity hydrocarbon expulsion period in Nanl Member, so, it is not favorable for hydrocarbon accumulation and storage in Nan2 Member.