摘要
基于鄂尔多斯盆地西部奥陶系克里摩里组地质条件,研究克里摩里组缝洞型储层条件、烃源岩条件和气藏特征,分析天然气运聚条件,建立不同地区的天然气成藏模式。研究表明,克里摩里组主要为角砾质灰岩,储集空间为裂缝和孔洞的缝洞系统,测井响应上具有高自然伽马、高声波时差和低电阻率的特点,连井剖面显示良好的连通性,其成因主要受到岩性和斜坡地貌控制;奥陶系乌拉力克组—拉什仲组泥灰岩和石炭系—二叠系煤系地层均为有效烃源岩,气源对比结果为克里摩里组天然气主要来自于煤系烃源岩。克里摩里组气藏主要为溶蚀缝洞型气藏,局部发育白云岩透镜体气藏,属于干气藏,具有顺层发育,呈现出似层状分布特点;结合天然气甲烷碳同位素和组分的分布特点,克里摩里组天然气成藏模式包括顺层输导"倒灌"型、直接"倒灌"型和断裂输导垂直"倒灌"型3种类型,分别处于拉什仲—乌拉力克组沉积区、克里摩里组暴露区和断层分布地区。
Based on geological conditions of Ordovician Kelimoli Formation in western Ordos Basin, fracture- cavity reservoir and source rock conditions as well as gas accumulation characteristics are studied, migration and accumulation features of natural gas are analyzed,and accumulation models in different areas are built. The results show that Kelimoli Formation is mainly composed of brecciated limestones. The storage space is a fracture-cavity system with logging response of high GR,high AC and low RT and it shows good con- nectivity through well-connecting profiles. Its origin is dominantly controlled by lithology and slope topog- raphy. Mud limestones from Ordovician Wulalike Formation to Lashizhong Formation and Carboniferous- Permian coal-bearing strata are effective source rocks. Gas source correlation results show that natural gas in the Kelimoli Formation is mainly from coal-measure source rocks. Kelimoli Formation mainly comprises dissolved fracture-cavity reservoir and local development of dolomite lens reservoir, both of which belong to dry gas reservoir and are featured by bedding-parallel development and stratiform-like distribution. Com- bined with methane carbon isotopes and components of natural gas, three gas accumulation models in the Kelimoli Formation are built,migration downward along carrier bed in the deposition area of Lashizhong- Wulalike Formation, migration downward directly in the exposed area of Kelimoli Formation, and migration downward vertically along faults in faulted zones.
出处
《天然气地球科学》
EI
CAS
CSCD
北大核心
2015年第10期1862-1872,共11页
Natural Gas Geoscience
基金
陕西省教育厅重点科研计划项目(编号:2015JS094)
西安石油大学博士启动基金(编号:134010179)联合资助
关键词
缝洞型储层
运聚条件
成藏模式
奥陶系
鄂尔多斯盆地
Fracture-cavity reservoir
Migration and accumulation condition
Accumulation model
Ordovician
Ordos Basin
