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渤海太古界变质岩潜山储层特征研究

Study on Reservoir Characteristics of the Archaean Metamorphic Rock Buried Hill in the Bohai Sea

Environment and Resource / 2026,8(1): 1-11 / 2026-01-23 115 79

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• Authors: 张敏 唐洪明
• Information:

  西南石油大学地球科学与技术学院，成都

• Keywords:
  Bozhong Sag; Metamorphic rock buried hill; Vertical zonation; Reservoir characteristics; Fracture
  渤中凹陷; 变质岩潜山; 纵向分带; 储层特征; 裂缝
• Abstract: B Oilfield, a 100-million-ton-class oil reservoir hosted in Archaean metamorphic rock buried hills, has been recently identified in the Bohai Bay Basin. Understanding the vertical reservoir properties is crucial the vertical reservoir properties is of crucial importance for the development of this oil accumulation. To this end, the present study carries out an investigation into the vertical reservoir characteristics by integrating multiple datasets, including XRD whole-rock clay analysis, cast thin section observations, and imaging logging data. Based on the degree of weathering, the Archaean metamorphic rock buried hill reservoir can be vertically stratified from top to bottom into three distinct zones: the intense weathering zone, the moderate weathering zone, and the internal basement zone. The dominant lithologies within these zones consist of migmatitic granite, cataclastic migmatitic granite, migmatitic granitic cataclasite, and migmatitic gneiss. From the intense weathering zone down to the internal basement zone, the reservoir displays consistent evolutionary trends: in terms of mineral composition, the relative abundances of quartz and clay minerals show a gradual decline, whereas those of feldspar and mica minerals increase steadily; with respect to clay mineral assemblages, the proportions of illite and kaolinite tend to decrease, while the contents of chlorite and illitesmectite mixed layers rise correspondingly. Overall, the reservoir is characterized by ultra-low porosity and ultra-low permeability, with its physical properties deteriorating progressively from top to bottom. Specifically, this deterioration is reflected in a reduced pore-throat radius, elevated displacement pressure, and weakened dissolution intensity. Concomitantly, the fracture aperture narrows, the fracture filling degree diminishes, and the fillings are predominantly composed of siliceous minerals, calcareous minerals, and mica. B油田是渤海湾盆地近年新发现的亿吨级太古界变质岩潜山油藏，明确其储层纵向特征对该油藏开发具有重要意义。本文依托XRD全岩黏土、铸体薄片、成像测井等资料，开展储层纵向特征研究。依据风化程度，太古界变质岩潜山储层自上向下可划分为强风化带、次风化带、内幕带三类，岩性以混合花岗岩、碎裂化混合花岗岩、混合花岗质碎裂岩及混合片麻岩为主。从强风化带到内幕带，储层呈现如下规律：矿物组成上，石英与黏土矿物相对含量递减，长石与云母矿物相对含量递增；黏土矿物组分中，伊利石、高岭石占比呈下降趋势，绿泥石与伊蒙混层占比则相应增加。储层整体表现为超低孔、超低渗特征，且物性自上向下逐渐变差，具体表现为孔喉半径缩小、排驱压力增大、溶蚀作用减弱；裂缝开度随之减小，充填程度降低，充填物主要为硅质、钙质及云母等。
• DOI: https://doi.org/10.35534/er.0801001 (registering DOI)
• Cite: 张敏，唐洪明．渤海太古界变质岩潜山储层特征研究［J］．环境与资源，2026，8（1）：1-11.