断裂对盖层封闭时间有效性破坏程度的研究方法及其应用

Research method of the destroy degree of the closed time effectiveness of the caprock by the faults and its application

为了研究含油气盆地断裂发育区油气分布规律,在盖层封闭时间有效性研究的基础上,通过确定断裂与盖层的封闭能力形成时期,建立了一套断裂对盖层封闭时间有效性破坏程度的研究方法,并将其应用于海拉尔盆地乌北凹陷苏仁诺尔油田F1断裂研究中。研究表明:苏仁诺尔油田大一段泥岩盖层约在伊敏组沉积末期开始形成封闭能力,而F1断裂与大一段泥岩盖层内断层岩封闭能力形成时期约为青元岗组二段沉积时期;F1断裂对大一段泥岩盖层封闭时间有效性破坏程度较高,使原来大一段泥岩盖层封油气较好的时间有效性变成现今断层岩封闭油气较差的时间有效性,不利于油气在其下聚集与保存。研究结果与苏仁诺尔油田油气分布相吻合,表明用该方法研究断裂对盖层封闭时间有效性破坏程度是可行的。

In order to study the oil and gas distribution rules in the fault developed zone of the petroleum basin, based on the research on the closed time effectiveness of the caprock, through the determination of the formed periods of the fault and the caprock sealing ability, a set of the research methods were established about the destroy degree of the closure time effectiveness of the caprock by the faults, and moreover applied in the study of Fault F1 in Surennuoer Oilfield of Wubei Sag in Hailar Basin. The study shows that the beginning to form the sealing ability for Member Da-1 mudstone caprock in Surennuoer Oilfield was from the depositional end period of Yimin Formation, while the formed periods of the sealing ability for Fault F1 and the fault rocks within Member Da-1 mudstone caprock were about the depositional period of Member-2 of Qingyuangang Formation;the damaged degree of the closure time effectiveness by Fault F1 for Member Da-1 mudstone caprock is rather higher, thus makes the much better time effectiveness of the oil and gas sealing for the previous Member Da-1 mudstone caprock become the rather poorer present fault-rock sealing, it is detrimental to the accumulation and preservation of the oil and gas. The research results are coincident with the oil and gas distribution of Surennuoer Oilfield, this indicates that the method is feasible to study the damaged degree of the closure time effectiveness of the caprock by the faults.