乐安油田地层油藏运聚过程研究

Study on hydrocarbon migration and accumulation process of stratigraphic reservoir in Lean Oilfield

宁方兴

Ning Fangxing1,2

中国石油大学(华东)地球资源与信息学院;胜利油田分公司地质科学研究院;

1.Geo-Resources and Information College, China University of Petroleum, Dongying 257061, China; 2.Geological Scientific Research Institute of Shengli Oilfield Company, SINOPEC, Dongying 257015, China

通过地质、地化、流体物性等资料的综合研究,明确了乐安油田地层油藏油气主要运移路线和过程。油源对比结果表明,乐安油田的油气来自博兴洼陷和牛庄洼陷沙四上亚段烃源岩。分析认为,油气运移的输导体系是由断层、砂体、不整合构成,以断层和砂体为主,不整合仅起局部垂向输导作用。来自牛庄洼陷的油气经过陈官庄断层进入乐安油田东区和广饶潜山;同时来自博兴洼陷的油气沿石村断层下降盘运移到草112井后分成两路:一部分油气进入石村断层上升盘与牛庄洼陷来的油气在草13块汇合后沿石村断层上升盘向东运移进入广饶潜山;另一部分则进入乐安油田南区。不整合以控藏作用为主,受不整合结构控制,在乐安油田形成3种类型的地层油藏:在不整合底板泥岩、风化黏土层、"硬壳"之上易形成地层超覆油气藏,在不整合顶板泥岩、不整合底板风化黏土层、"硬壳"之下易形成地层不整合遮挡油气藏和潜山油气藏。

 Tertiary and Quaternary of the southern margin in Junggar Basin is the period of rejuvenated foreland basin. On the basis of the research outcomes of sequence stratigraphy at the southern margin of Junggar Basin, Neocene Shawan Formation and Taxihe Formation were divided into one second-grade sequence and two third-grade sequences full taking use of the field outcrop, drilling and logging. According to the different stages of tectonic evolution and their corresponding deposition composition, two sequences were generalized to two types, which were tectonic sequence and climate sequence. The inner of every sequence type may be divided into lowstand system-tract, transgressive system-tract and highstand system-tract. The development of tectonic sequence is obviously influenced by the thrust tectonism and the development of climate sequence is mainly influenced by the change of relative lake level which is caused by the climate. Based on the characteristics of the inner contexture development of two types sequences, and combined with the special tectonic location where the foothill belt lies and the different evolution stages of sequence development, the development models of Neocene sequence at the southern margin of Junggar Basin are summarized as the steep slope type and climate type.