准噶尔盆地南缘西段白垩系清水河组储层成岩作用及孔隙演化

Diagenesis and pore evolution of Cretaceous Qingshuihe Formation reservoir in western section of southern margin of Junggar Basin

王剑 高崇龙 白雷 向宝力 刘金 鲜本忠 连丽霞 刘可

WANG Jian GAO Chonglong BAI Lei XIANG Baoli LIU Jin XIAN Benzhong LIAN Lixia LIU Ke

中国石油 新疆油田分公司 实验检测研究院，新疆 克拉玛依 834000 中国石油 砾岩油气藏勘探开发重点实验室，新疆 克拉玛依 834000 新疆砾岩油藏实验室，新疆 克拉玛依 834000 中国石油大学(北京) 克拉玛依校区 石油学院，新疆 克拉玛依 834000 中国石油大学(北京) 地球科学学院，北京 102249 东北石油大学 地球科学学院，黑龙江 大庆 163318

Research Institute of Experiment and Detection, Xinjiang Oilfield Company, PetroChina, Karamay, Xinjiang 834000, China CNPC Key Laboratory of Conglomerate Reservoir Exploration and Development, Karamay, Xinjiang 834000, China Xinjiang Laboratory of Petroleum Reserves in Conglomerate, Karamay, Xinjiang 834000, China College of Petroleum, China University of Petroleum-Beijing at Karamay, Karamay, Xinjiang 834000, China College of Geosciences, China University of Petroleum (Beijing), Beijing 102249, China College of Geosciences, Northeast Petroleum University, Daqing, Heilongjiang 163318, China

准噶尔盆地南缘西段白垩系清水河组具有十分优越的油气勘探前景，系统研究其成岩作用特征及孔隙演化过程，明确有利储层发育区，可以为后期油气精细勘探评价提供指导。基于普通薄片、铸体薄片、全岩X衍射、粒度、扫描电镜、碳酸盐胶结物碳氧同位素与流体包裹体分析，综合研究准南西段清水河组成岩特征及其孔隙演化过程，并进一步探讨了不同成岩相间的储层孔隙演化过程差异。研究表明：(1)研究区清水河组储层以砂砾岩为主，岩屑含量高，平均占比65.97%，并以凝灰岩岩屑为主。胶结物主要为方解石。储层平均孔隙度为6.2%，平均渗透率为7.45×10-3 μm2，整体表现为低孔—低渗型的致密储层，但局部仍有优质储层发育；(2)储层埋藏方式以长期浅埋—晚期快速深埋为特征，并可进一步划分出长期浅埋、构造抬升至近地表、正常深埋和快速深埋4个演化阶段。其中在长期浅埋、构造抬升至近地表、正常深埋阶段储层成岩演化处于早成岩A期，而快速深埋阶段储层处于早成岩B期—中成岩A期；(3)清水河组储层可划分出4种典型成岩相，即强压实相、钙质/铁泥质强胶结相、凝灰质充填—弱溶蚀相和弱压实—孔隙发育相，并以成岩相为约束建立准噶尔盆地南缘清水河组碎屑岩储层孔隙演化模式。弱压实—孔隙发育相为优质储层成岩相类型，其次为凝灰质充填—弱溶蚀相。

The Qingshuihe Formation in the western section of the southern margin of the Junggar Basin has excellent oil and gas exploration prospects. The systematic study of its diagenesis characteristics and pore evolution process will provide guidance for the later fine exploration and evaluation of oil and gas. Therefore, based on the analysis of ordinary thin sections, cast thin sections, whole rock X-ray diffraction, grain size, scanning electron microscopy, carbon and oxygen isotopes of carbonate cements and fluid inclusions, the diagenesis characteristics and pore evolution process of the Qingshuihe Formation in the western section of the southern margin of the Junggar Basin were systematically studied, and the differences of reservoir pore evolution process between different diagenetic facies were further discussed. The study shows that: (1)The reservoir of the Qingshuihe Formation in the studied area is dominated by glutenite. The content of rock debris is high, with an average of 65.97%, mainly tuff rock debris. The cement is mainly calcite. The average porosity of the reservoir is 6.2%, and the average permeability is 7.45×10-3 μm2. It is generally a tight reservoir of low porosity and low permeability, but high-quality reservoirs are still developed locally; (2)The reservoir burial mode of the Qingshuihe Formation in the southern margin of the Junggar Basin is characterized by long-term shallow burial and late rapid deep burial, and can be further divided into four evolutionary stages: long-term shallow burial, tectonic uplift to near surface, normal deep burial, and rapid deep burial. The diagenetic evolution of the reservoir was in early diagenetic stage A in the long-term shallow burial, tectonic uplift to near surface, and normal deep burial stages, while in the rapid deep burial stage, the reservoir was in early diagenetic stage B to middle diagenetic stage A; (3)The reservoir of the Qingshuihe Formation can be divided into four typical diagenetic facies types, namely, strong compaction facies, calcareous/iron argillaceous strong cementation facies, tuffaceous filling weak dissolution facies, and weak compaction pore development facies. The pore evolution model of the clastic rock reservoir of the Qingshuihe Formation in the southern margin of the Junggar Basin was established based on the constraints of diagenetic facies. The weak compaction pore development facies are high-quality reservoir diagenetic facies, followed by tuffaceous filling weak dissolution facies.

国家科技重大专项 2017ZX05008-004-008;新疆维吾尔自治区重点实验室开放课题 2017D04023

https://doi.org/10.11781/sysydz202304632