石油与天然气地质 ›› 2022, Vol. 43 ›› Issue (5): 1206-1220.doi: 10.11743/ogg20220516

• 油气地质 • 上一篇    下一篇

准噶尔盆地玛湖凹陷二叠系风城组页岩储层润湿性及其主控因素

郑国伟1,2(), 高之业1,2(), 黄立良3, 姜振学1,2, 何文军3, 常佳琦1,2, 段龙飞1,2, 魏维航1,2, 王志伟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) 非常规油气科学技术研究院,北京 102249
    3.中国石油 新疆油田分公司 勘探开发研究院,新疆 克拉玛依 834000
  • 收稿日期:2021-09-14 修回日期:2022-07-13 出版日期:2022-10-01 发布日期:2022-09-02
  • 通讯作者: 高之业 E-mail:zhengguowei7@163.com;gaozhiye@163.com
  • 第一作者简介:郑国伟(1997—),男,硕士研究生,非常规油气储层评价。E?mail: zhengguowei7@163.com
  • 基金项目:
    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(ZLZX2020-01-05);国家自然科学基金项目(41972145)

Wettability of the Permian Fengcheng Formation shale in the Mahu Sag, Junggar Basin, and its main control factors

Guowei Zheng1,2(), Zhiye Gao1,2(), Liliang Huang3, Zhenxue Jiang1,2, Wenjun He3, Jiaqi Chang1,2, Longfei Duan1,2, Weihang Wei1,2, Zhiwei Wang1,2   

  1. 1.State Key Laboratory of Petroleum Resources and Prospecting,China University of Petroleum (Beijing),Beijing 102249,China
    2.Unconventional Petroleum Research Institute,China University of Petroleum (Beijing),Beijing 102249,China
    3.Research Institute of Exploration and Development,Xinjiang Oilfield Company,PetroChina,Karamay,Xinjiang 834000,China
  • Received:2021-09-14 Revised:2022-07-13 Online:2022-10-01 Published:2022-09-02
  • Contact: Zhiye Gao E-mail:zhengguowei7@163.com;gaozhiye@163.com

摘要:

页岩储层润湿性会对储层相对渗透率、毛细管力产生重要影响,并最终影响页岩油气成藏过程和采收率。以准噶尔盆地玛湖凹陷二叠系风城组页岩为研究对象,综合利用接触角、自发渗吸+微米CT等多种实验手段对页岩储层润湿性特征及其主控因素进行研究。研究结果显示:①玛湖凹陷风城组页岩为偏向亲油的混合润湿,不同岩相的水润湿能力依次为长英质页岩>含灰长英质页岩>含云长英质页岩>含长英云质页岩>粉砂岩。②页岩润湿性受有机质丰度、矿物组分和孔隙结构等多因素共同控制,页岩亲油性与总有机碳含量、白云石含量呈正相关,与石英含量呈负相关,与方解石含量呈分段式相关;宏孔孔体积越大,页岩亲油性越强。③亲油孔隙连通性沿着裂缝和纹层发育的方向会变好;云质团块会形成聚集型的、具有一定连通性的孔隙系统,同页岩基质中连通的小孔隙一起构成云质团块特有的页岩油储集空间和运移通道。④小于1 μm的孔隙连通性较好,为页岩油的主要运移通道;大于1 μm的孔隙连通性差,是页岩油主要的储集空间。⑤依据不同岩相润湿性特征和沉积构造特征初步确定研究区优质储层为发育裂缝、云质团块、纹层构造的粉砂岩和含云长英质页岩。

关键词: 微米CT, 自发渗吸, 接触角, 页岩润湿性, 孔隙连通性, 页岩储层, 玛湖凹陷, 准噶尔盆地

Abstract:

Shale wettability is of great significance to relative permeability and capillary force of a reservoir, ultimately affecting the hydrocarbon accumulation process in shale as well as the shale oil/gas recovery rate. This study focuses on the wettability characteristics and main control factors of the Permian Fengcheng Formation shale in the Mahu Sag, Junggar Basin, by means of contact angle measurement and spontaneous imbibition plus micro-CT experiment. The results are shown as follows. First, the Fengcheng Formation shale in the Mahu Sag is of generally mixed wettability while prone to oil-wet, and the affinity of different lithofacies to water is listed out from the top, that is, felsic shale, limy felsic shale, dolomitic felsic shale, felsic dolomitic shale, and siltstone. Second, the shale wettability is jointly controlled by multiple factors including organic matter abundance, mineral composition, and pore structure. The shale hydrophobicity is positively correlated with the TOC, dolomite content, negatively with the quartz content, and in staged correlation with the calcite content; the larger the pore volume occupied by macro-pores, the more oil-wet is the shale sample. Third, the connectivity of oil-wet pores tends to grow better along the direction of crack and lamina development. A pore system of clustered type and certain connectivity is prone to form in dolomitic glomerates, which can form an unique shale oil storage space and migration pathway together with the interconnected small pores in the shale matrix. Fourth, the pores less than 1 μm have better connectivity and act as the main migration pathways for shale oil, while those larger than 1 μm with poor connectivity serve as the main storage space for shale oil. Fifth, it is preliminarily concluded that the high-quality shale oil reservoirs are of siltstone and dolomitic felsic shale with well-developed cracks, dolomitic glomerates and laminar structures in the study area according to the wettability characteristics of different lithofacies and sedimentary structure characteristics.

Key words: micro-CT experiment, spontaneous imbibition, contact angle, shale wettability, pore connectivity, shale reservoir, Mahu Sag, Junggar Basin

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