石油与天然气地质 ›› 2020, Vol. 41 ›› Issue (2): 235-247, 294.doi: 10.11743/ogg20200201

• 油气地质 • 上一篇    下一篇

渤海海域太古界深埋变质岩潜山优质储集层形成机制与油气勘探意义

徐长贵(), 杜晓峰, 刘晓健, 徐伟, 郝轶伟   

  1. 中海石油(中国)有限公司 天津分公司, 天津 300459
  • 收稿日期:2018-09-11 出版日期:2020-04-28 发布日期:2020-04-03
  • 作者简介:徐长贵(1971-),男,博士、教授级高级工程师,石油地质与综合勘探。E-mail:xuchg@cnooc.com.cn
  • 基金资助:
    国家科技重大专项(2016ZX05024-003-001)

Formation mechanism of high-quality deep buried-hill reservoir of Archaean metamorphic rocks and its significance in petroleum exploration in Bohai Sea area

Changgui Xu(), Xiaofeng Du, Xiaojian Liu, Wei Xu, Yiwei Hao   

  1. Tianjin Branch of CNOOC Ltd., Tianjin 300459, China
  • Received:2018-09-11 Online:2020-04-28 Published:2020-04-03

摘要:

深埋变质岩潜山风化壳相对致密,裂缝发育程度是储层优质的决定因素。利用岩心、铸体薄片、荧光薄片、扫描电镜、常规物性等实验分析方法,对渤海海域渤中19-6构造太古界深埋变质岩潜山优质储集层形成机制进行分析。研究表明,渤中19-6构造太古界以片麻岩、变质花岗岩和混合岩为主,岩石中长英质矿物含量高、地层脆性强,极易形成裂缝,为优质储集层的发育创造了较好的岩性条件;持续动力破碎作用使潜山内幕发育大规模裂缝发育带和动力破碎带,是变质岩优质储集层形成的关键;风化作用影响下潜山顶部形成大量次生溶蚀孔和沿裂缝溶蚀扩大孔,但深埋作用使顶部风化壳相对致密。在上述控制因素指导下,建立了“垂向贯通,横向连续”大型深埋变质岩优质储集层分布模式。

关键词: 变质岩, 优质储集层, 潜山, 太古界, 渤中19-6构造, 渤中凹陷, 渤海海域

Abstract:

The weathering crust of deep metamorphic rocks is relatively dense, and the development of fractures is key to reservoir quality.The formation mechanism of high-quality buried-hill reservoir of deep Archaean metamorphic rocks in the BZ 19-6 structure was analyzed through core description, casting thin section observation, microscopic fluorescent analysis of thin section, scanning electron microscopy and conventional physical property measurements.The results show that the Archaean rocks in the BZ 19-6 structure are dominated by gneiss, metamorphic granite and migmatite, in which the high content of felsic minerals with great brittleness is prone to fracture development.Thus, they tend to develop high-quality reservoirs.The fragmentation under continuous deformation and stress makes large-scale fracture zones and stress fragmenting zones developed inside the buried hill, which is the key to the formation of high-quality reservoirs in metamorphic rocks.The weathering resulted in a large number of secondary dissolution pores and dissolution enlarged pores along fractures on top of the buried hill.However, the weathering crust became relatively dense under deep burial.Under the guidance of controlling factors mentioned above, a reservoir distribution pattern of "vertical connectivity, and lateral continuity" is revealed for large-scale deep metamorphic reservoirs of high quality.

Key words: metamorphic rock, high-quality reservoir, buried hill, Archaean, BZ 19-6 structure, Bozhong Depression, Bohai Sea area

中图分类号: