油气地质与采收率2025，Vol.32Issue(2)：25-35,11.DOI:10.13673/j.pgre.202401042
鄂尔多斯盆地富县地区碳酸盐岩储层风化裂缝成因类型及其对油气富集的影响
Genetic types of weathering-induced fractures in carbonate reservoirs in Fuxian area of Ordos Basin and their impact on hydrocarbon enrichment
摘要
Abstract
The Lower Paleozoic carbonate rocks in the Ordos Basin are characterized by substantial depositional thickness and exten-sive distribution,with reservoirs exhibiting tight lithology,low porosity,and low permeability.The accumulation and migration of natural gas in these carbonate reservoirs are significantly influenced by storage and flow space composed of fractures and pores.Based on analytical results from core samples,thin-section observations,and production data,this study investigated the genetic types of weathering-induced fractures in Majiagou Formation of Fuxian area and their impact on hydrocarbon accumulation.The re-sults demonstrate that weathering-induced fractures in the carbonate reservoirs are controlled by lithology,paleokarst geomorphol-ogy,and fault scale,and they can be classified into three types:karst-collapse fractures,weathering-leached fractures,and scarp-related tensile fractures.Karst-collapse fractures predominantly develop in soluble gypsum-bearing dolomites and evaporites within residual hills;weathering-leached fractures occur in dolomitic limestones on slopes and terraces;scarp-related tensile fractures form in dolomite-poor argillaceous limestones at steep unconformity surfaces.Among these fracture types,karst-collapse fractures create effective fracture networks that enhance reservoir porosity and permeability.Scarp-related tensile fractures exhibit moderate effec-tiveness,primarily improving permeability but failing to form complex fracture networks.Weathering-leached fractures,often me-chanically filled,contribute minimally to reservoir porosity and permeability.According to production dynamics,the carbonate res-ervoirs in the study area are categorized into four types:karst-collapse fracture-dominated,scarp-related tensile fracture-dominated,weathering-leached fracture-dominated,and matrix-ineffective reservoirs.关键词
天然裂缝/发育特征/富集成藏/马家沟组/鄂尔多斯盆地Key words
natural fracture/developmental characteristic/enrichment formation/Majiagou Formation/Ordos Basin分类
石油、天然气工程引用本文复制引用
毛金昕,何建华,解馨慧,邓虎成,王瑕,曹峰,邢梓萌..鄂尔多斯盆地富县地区碳酸盐岩储层风化裂缝成因类型及其对油气富集的影响[J].油气地质与采收率,2025,32(2):25-35,11.基金项目
国家自然科学基金青年基金项目"前陆盆地湖相页岩储层纤维状方解石脉体结构形成机制与时空演化序列"(42402148),"颗粒排列结构对页岩储层剪切模量的控制机制"(42402169). （42402148）
