准噶尔盆地玛南斜坡区上二叠统上乌尔禾组连续型砂砾岩油藏群成藏特征

Accumulation characteristics of continuous sand conglomerate reservoirs of Upper Permian Upper Wuerhe Formation in Manan slope area, Junggar Basin

黄立良 王然 邹阳 万敏 常秋生 钱永新

HUANG Liliang WANG Ran ZOU Yang WAN Min CHANG Qiusheng QIAN Yongxin

中国石油 新疆油田公司 勘探开发研究院, 新疆 克拉玛依 834000

Institute of Exploration and Development, PetroChina Xinjiang Oilfield Company, Karamay, Xinjiang 834000, China

准噶尔盆地玛湖凹陷（玛南）斜坡区上二叠统上乌尔禾组新近发现了大型的连续型砂砾岩油藏群。为及时总结、丰富发展连续型油气地质理论，并为深化下步区域勘探提供依据，在对这些油藏群进行精细构造解释、沉积体系研究及储盖组合分析的基础上，研究了成藏要素和油藏特征。结果表明，玛南斜坡区风城组烃源岩分布广、厚度大、类型好、成熟度高；中拐扇、克拉玛依扇、白碱滩扇和达巴松扇四大物源体系内乌一段和乌二段砂砾岩储层叠置连片发育，与乌三段广泛发育的泥岩盖层构成稳定的储盖组合；近东西向深大走滑断裂与全凹发育的不整合面组合，是油气运聚的立体输导通道。上乌尔禾组为“前陆—坳陷”转换期填平补齐式的沉积，在大型地层尖灭带背景下，大面积岩性圈闭连续发育，形成了一系列地层型、岩性型、断层—岩性型等油藏群。中拐扇和克拉玛依扇勘探程度较高，但仍存在较多剩余出油气井点，是储量拓展的潜力区；相比而言，白碱滩扇和达巴松扇沉积背景与中拐扇类似，但勘探程度低，是甩开勘探的重点区带。

A large continuous conglomerate reservoir has been recently discovered in the Upper Permian Upper Wuerhe Formation on the southern slope of Mahu Sag, Junggar Basin. In order to timely summarize, enrich and develop the theory of continuous oil and gas geology, and to provide a basis for deepening regional exploration, it was studied in this paper the reservoir forming elements and reservoir characteristics based on the fine structure interpretation, sedimentary system study and reservoir-cap combination analysis of these reservoirs. The results showed that the source rocks of Fengcheng Formation on the southern slope were widely distributed, with a large thickness, good type and high maturity. In four major material source systems including Zhongguai, Karamay, Baijiantan and Dabasong fans, the sand conglomerate reservoirs in the first and second members of Upper Wuerhe Formation overlapped continuously, and formed a stable reservoir-caprock assemblage with the widely developed mudstone caprock of the third member of Upper Wuerhe Formation. Near EW-oriented deep strike-slip faults and unconformities widespread in the sag provided pathways for hydrocarbon migration and accumulation. The Upper Wuerhe Formation is a "foreland-depression" replacement-type deposit. Under the background of large formation pinch-out zone, a large area of continuous lithologic traps was developed, forming stratigraphic, lithologic and fault-lithologic oil reservoirs. The Zhongguai and Karamay fans are found to have a high potential for exploration and still have many remaining oil and gas points. The Baijiantan and Dabasong fans have similar sedimentary background with the Zhongguai fan, and have a lower exploration degree, which are key area for future exploration.

国家科技重大专项“准噶尔盆地岩性地层油气藏富集规律与目标评价” 2017ZX05001-004

https://doi.org/10.11781/sysydz202201051