阿尔及利亚三叠盆地GUERARA地区石油地质条件分析

ANALYSIS OF PETROLEUM GEOLOGICAL CONDITIONS OF THE GUERARA BLOCK IN THE TRIASSIC BASIN,ALGERIA

GUERARA区块位于阿尔及利亚三叠盆地北部,该盆地油气资源十分丰富,阿尔及利亚油气原始地质储量的70%位于该盆地。盆地内目前发现的油气藏类型主要为岩性、地层尖灭及背斜复合型油气藏。区内主要烃源岩为志留系海相泥岩,次为奥陶系泥岩;主要储层为三叠系砂岩,次为奥陶系及寒武系石英砂岩。构造圈闭以低幅度背斜为主。在对该区基本成藏地质条件研究的基础上,指出志留系烃源岩的发育程度及储层物性控制油气藏分布;海西不整合面及其上下砂岩为油气侧向运移提供了路径,北东向断层及伴生的微裂缝为油气的纵向运移提供了通道,并优选出该区阿古圈闭发育带和布艾沙圈闭发育带是油气勘探突破的有利区带。

The Guerara block is located in the north of Triassic Basin which is rich in oil and gas resources with its original hydrocarbon accumulations accounting for 70% of Algeria. The main reservoir type is composite reservoir which are lithologic, stratigraphic pitch-out and anticline hydrocarbon reser- voirs. In the study area, the main source rocks are Silurian marine mudstone and the secondary is Ordovi- cian mudstone. The main reservoir rock is Triassic sandstone and the secondary is Ordovician and Cam- brian quartz sandstone. The structural traps is mainly anticline with low amplitude. Based on the research of basic accumulation geological conditions, it shows that the occurrence of Silurian hydrocarbon source rocks and petrophysics properties of reservoir are controlling factors of reservoir distribution. The Hercynian unconformity surface and its sandstone in the upper and lower provide the pathway for lateral migation of oil and gas. North-east trending fault and its associated micro-fractures provide the pathway for the vertical migration of oil and gas. The traps-growing belts in Argoub and Bouaicha are selected favorably for breakthrough of future exploration.