形成规模油田成烃要素下限探讨——以东濮凹陷马寨油田为例

Lower limit discussion of hydrocarbon generation factor for large scale oilfield:taking Mazhai Oilfield of Dongpu Depression as an example

随着勘探程度日益加深,我国东部老油区大油气田逐步发现殆尽,小洼陷的油气勘探渐成勘探热点。文中根据有机地球化学理论解剖了东濮凹陷独立含油气系统的马寨油田,探讨了形成千万吨级规模储量油田必需的成烃要素下限。研究认为形成千万吨级规模储量油田至少需具备3个要素:1)成熟烃源岩镜质组反射率至少大于0.6%,其对应埋藏深度至少大于3 000 m;2)总有机碳质量分数大于或等于1.0%的烃源岩厚度至少在279 m以上;3)生烃强度大于50×104t/km^2的烃源岩面积至少50 km^2。

Along with the increasing degree of exploration,most of the large scale oil and gas fields have been discovered in the old oilfields in eastern China.It is particularly urgent to solve these problems,and therefore it becomes a hot spot that explorers turn the direction of exploration from basin to smaller depression.In response to this hot spot,using organic geochemical techniques,the Mazhai Oilfield with independent hydrocarbon system in Dongpu Depression was dissected.Meanwhile there is a discussion about the lower limit of hydrocarbon generating factors for the formation of 10-million-ton scale oilfield reserves.The results show that there are at least three elements that are the necessary for the formation of 10-million-ton scale oilfield reserves:the mature hydrocarbon source rock is buried at least more than 3,000 m,and its mirror body reflectivity is at least greater than 0.6%;hydrocarbon source rock thickness is at least 279 m,and the TOC content of the source rocks is more than 1.0%;hydrocarbon generating strength is greater than 50×10^4 t/km^2,and the area is at least 50 km^2.