LAUSR

Based on the drilling, cores, logs, seismic, laboratory analysis and so on, reservoir characteristics and hydrocarbon accumulation of Carboniferous volcanic weathered crust in Zhongguai high area are studied. Volcanic rocks were formed in an island arc environment. The lithology is mainly andesite and tuff; Reservoir spaces are mainly secondary pore, fracture and their combination forms, fractures have a better effect on reservoir seepage; There are four layer structures of volcanic weathered crust, weathered clay layer, strongly weathered zone, weakly weathered zone and unweathered zone and strongly weathered zone is the best, which is the main reservoir development zone; The development of reservoir is mainly affected by weathering-leaching, lithology and lithofacies, and fault (fracture); Effective reservoirs could reach to 480 m thickness (high quality reservoirs are within 240 m). Carboniferous volcanic reservoirs are distributed along three zones, which are near the fault zone, high structural part, favorable lithofacies development zone, and one plane, which is near the unconformity.摘要综合利用钻井、岩心、测井、地震、分析化验等资料, 对准噶尔盆地西北缘中拐地区石炭系火 山岩风化壳储层特征及油气成藏开展综合研究。研究表明:研究区石炭系火山岩形成于岛弧环境; 岩 性以安山岩、凝灰岩为主; 有效储集空间以次生孔隙、裂缝以及它们的组合形式为主, 裂缝的发育改 善了储层渗流能力; 石炭系火山岩风化壳结构分为风化黏土层、强风化带、弱风化带及致密未风化带 4 层结构, 其中强风化带储层物性最好, 为主要的储层发育区; 风化壳储层主要受风化淋滤作用、岩 性岩相、构造位置及断裂(裂缝)等因素的控制, 有效储层厚度分布在深度480 m 以内(优质储层在 240 m 以内)。石炭系储层的富集规律为沿三带(靠近断裂带、构造高部位地带、有利岩相发育带)、 一面(不整合面附近)分布。