Characteristics of parametamorphic rock reservoirs in Pingxi area, Qaidam Basin, NW China

• 作者: LI Senming LIU Zhanguo TIAN Mingzhi WANG Bo WU Jin XIA Zhiyuan ZHANG Yongshu ZOU Kaizhen
• 来源期刊: 石油勘探与开发:英文版
• 学科: 地球科学
• 关键词: Qaidam Basin Pingxi area parametamorphic ROCK RESERVOIR ROCK type pore THROAT CHARACTERISTICS RESERVOIR formation RESERVOIR distribution
• 年，卷（期）: 2019,（1）
• 页码范围: 93-103
• 页数: 11页
• 分类号: P618.13

摘要

Based on core, thin-section, scanning electron microscopy(SEM) and well logging data, the characteristics of the parametamorphic rock reservoirs in the Pingxi area were analyzed by means of whole rock X-ray diffraction and micron CT scanning. The parametamorphic rock reservoirs mainly had three types of rocks: slate, crystalline limestone and calc-schist;the original rocks were Ordovician-Silurian marine clastic and carbonate rocks. The three types of parametamorphic rock reservoirs developed three types and six sub-types of reservoir space. The first type of reservoir space was fractures, including structural, weathered and dissolution fractures;the second type was dissolved porosities, including dissolved pores and caves;the third type was nano-sized intercrystalline porosities. The three types of parametamorphic rock reservoirs were different widely in the quantity, volume and radius of pore-throats, and were strongly affected by the type and development degree of fractures. The parametamorphic rock reservoirs were formed by metamorphism, weathering, structural fragmentation and dissolution. Metamorphism reformed the parametamorphic rock reservoirs significantly, breaking the traditional constraint of finding weathering crust at top. The parametamorphic rock reservoirs experienced five formation stages, and their distribution was controlled by rock type, metamorphic degree, ancient geomorphology, and weathering intensity.