石油学报 ›› 2022, Vol. 43 ›› Issue (7): 941-956,976.DOI: 10.7623/syxb202207005

• 地质勘探 • 上一篇    下一篇

鄂尔多斯盆地庆城地区延长组7段源-储结构控制下致密砂岩油的差异富集机制

王福伟1,2, 陈冬霞1,2, 解广杰3, 李士祥4, 曾溅辉1,2, 姚东升1,2, 成铭1,2   

  1. 1. 中国石油大学(北京)油气资源与探测国家重点实验室 北京 102249;
    2. 中国石油大学(北京)地球科学学院 北京 102249;
    3. 中国石油化工股份有限公司江苏油田分公司采油一厂 江苏扬州 225265;
    4. 中国石油长庆油田公司勘探开发研究院 陕西西安 710018
  • 收稿日期:2021-09-18 修回日期:2021-12-01 出版日期:2022-07-25 发布日期:2022-08-01
  • 通讯作者: 陈冬霞,女,1974年11月生,2003年获中国石油大学(北京)博士学位,现为中国石油大学(北京)教授、博士生导师,主要从事油气藏形成机理与分布规律方面的教学和科研工作。Email:lindachen@cup.edu.cn
  • 作者简介:王福伟,男,1996年1月生,2017年获西南石油大学学士学位,现为中国石油大学(北京)地质资源与地质工程专业博士研究生,主要从事油气藏形成机理与分布规律研究。Email:wangfw_cup@163.com
  • 基金资助:
    中国石油天然气集团有限公司-中国石油大学(北京)战略合作科技专项(ZLZX2020-02-01-03)资助。

Differential enrichment mechanism of tight sandstone oil under the control of the source-reservoir structures of Member 7 of Yanchang Formation in Q ingcheng area,Ordos Basin

Wang Fuwei1,2, Chen Dongxia1,2, Xie Guangjie3, Li Shixiang4, Zeng Jianhui1,2, Yao Dongsheng1,2, Cheng Ming1,2   

  1. 1. State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum, Beijing 102249, China;
    2. College of Geosciences, China University of Petroleum, Beijing 102249, China;
    3. No. 1 Oil Production Plant of Sinopec Jiangsu Oilfield Company, Jiangsu Yangzhou 225265, China;
    4. Research Institute of Exploration and Development, PetroChina Changqing Oilfield Company, Shaanxi Xi'an 710018, China
  • Received:2021-09-18 Revised:2021-12-01 Online:2022-07-25 Published:2022-08-01

摘要: 基于砂地比及岩性厚度对鄂尔多斯盆地庆城地区延长组7段的源-储结构进行了系统划分,利用油井占比、有效充注强度和含油饱和度表征了不同源-储结构的含油性,揭示了源-储结构控制下致密砂岩油的差异富集机制。结果表明:鄂尔多斯盆地庆城地区延长组7段发育储夹源型、源储互层型和源夹储型3类一级源-储结构,其整体含油性依次降低,而在与其对应的9种二级源-储结构中以"厚储夹薄源型"、"厚储夹中源型"、"厚源厚储互层型"和"中源中储互层型"源-储结构的含油性最高。综合分析表明,受延长组7段3亚段黑色页岩和延长组7段1亚段+2亚段暗色泥岩供烃能力控制,不同源-储结构的纵向组合序列决定了供烃条件,其中,底部型源-储结构组合序列的供烃条件依次优于中间型和顶部型;致密砂岩油在异常压力驱动下沿剩余压力高值区向低值区充注,这使得剩余压力相对低的储夹源型和源储互层型源-储结构成为致密砂岩油聚集的有利部位,且充注强度随剩余压力的减小而增大;不同源-储结构内发育了类型和规模不同的裂缝系统,这使得以穿层高角度构造裂缝为主导的储夹源型源-储结构更有利于致密砂岩油垂向运移,而以层理缝、水平缝和层内低角度缝为主导的源夹储型源-储结构则限制了垂向运移距离,导致致密砂岩油在纵向上分布差异。最后,在储层非均质性控制下,致密砂岩油在孔隙度大于6%和渗透率大于0.02 mD的储层"甜点"内聚集,使得"甜点"发育的储夹源型和源-储互层型源-储结构内富集了大规模致密砂岩油,并在源-储结构"序(纵向组合序列)—压(异常压力)—缝(裂缝系统)—储(储层甜点)"的控制下呈现出6种不同的富集模式。

关键词: 源-储结构, 致密砂岩石油, 富集机制, 延长组7段, 庆城地区, 鄂尔多斯盆地

Abstract: Based on the sandstone percentage and lithological thickness, this paper systematically classifies the source-reservoir structures of Member 7 of Yanchang Formation in Qingcheng area, Ordos Basin. Furthermore, the oil-bearing properties of different source-reservoir structures are characterized using the proportion of oil wells, effective charging intensity and oil saturation, thereby revealing the differential enrichment mechanism of tight sandstone oil under the control of source-reservoir structures. The results show that the Member 7 of Yanchang Formation can be divided into three types of primary source-reservoir structures, namely reservoir sandwiching source (Type 1), source-reservoir interbedding (Type 2), and source sandwiching reservoir (Type 3), and their oil contents as a whole decrease successively. Correspondingly, among the 9 types of secondary source-reservoir structures, thick reservoir sandwiching thin source rock, thick reservoir sandwiching medium-thickness source rock, thick source-thick reservoir interbeding, and medium thickness source-reservoir interbedding have the highest content of oil. The comprehensive analysis proves that as controlled by the hydrocarbon generation capacity of black shale in the third submember and dark mudstone in the first and second submember of Member 7 of Yanchang Formation, the vertical combination sequence of source-reservoir structure determines the hydrocarbon supply conditions; specifically, the combination sequence of the source-reservoir structure in the bottom section has better hydrocarbon supply conditions than that in the middle and top section. Subsequently, the tight sandstone oil is charged from an area of high residual pressure area to an area of low residual pressure area. This has led to the result that the Type 1 and 2 source-reservoir structures with relatively low residual pressure have become favorable locations for tight sandstone oil accumulation, and the charging strength usually increases as the residual pressure decreases. Additionally, the fracture systems of different types and scales have been developed in various types of source-reservoir structures. As a result, Type 1 structure dominated by high-angle transverse structural fractures is more conducive to the vertical migration of tight sandstone oil, while Type 3 structure dominated by bedding, horizontal and low-angle fractures has restricted the vertical migration distance, resulting in the difference in the longitudinal distribution of tight sandstone oil. Finally, under the control of the reservoir heterogeneity, tight sandstone oil accumulates in sweet spots with the porosity greater than 6% and the permeability greater than 0.02 mD. For this reason, tight sandstone oil is enriched in the Type 1 and 2 structure with large-scale sweet spots, showing 6 different enrichment modes of tight sandstone oil under the control of the sequence (vertical combination sequence) -pressure (abnormal pressure) -fracture (fracture system) -reservoir (sweet spots) of source-reservoir structures.

Key words: source-reservoir structure, tight sandstone oil, enrichment mechanism, Member 7 of Yanchang Formation, Qingcheng area, Ordos Basin

中图分类号: