摘要
针对火山岩风化壳储层控制因素和成因复杂的难题,以三塘湖盆地石炭系卡拉岗组为例,在搞清晚石炭世构造环境和岩性特征基础上,提出风化淋滤和断裂改造是火山岩风化壳形成有利储层的主要控制因素。不同火山岩岩性经风化淋滤后储层物性均增大并能形成有利储层,储集层孔隙类型以次生溶蚀孔隙和裂缝为主,具双峰分布特征。建立了5层结构模型,并提出通过岩芯识别火山岩风化体方法,指出不同风化体结构层中的孔隙类型和岩石结构不同,其中溶蚀带和崩解带是有利储层发育段,火山岩风化体厚度可达380 m,受断裂控制的火山岩风化体发育中低角度裂缝,储层物性更好、厚度更大,火山岩风化体主要发育于古地貌高部位和斜坡带,沿断裂处更发育。该认识改变了古生界火山岩成岩作用强、储集性能差,不能形成有利储层的认识,扩大了油气勘探领域,对指导火山岩风化体油气勘探具有重要的科学意义,并指出中国中西部含油气盆地古生界发育大规模火山岩风化体,是今后油气勘探的新领域。
Focusing on the controlling factors and complex origin of weathering volcanic reservoir,this study took the Kalagang Formation of Carboniferous in Santanghu basin as an example in order to figure out the major controlling factors of favorable weathering volcanic reservoir.Based on understanding of the tectonic background and lithologic characteristics of the late Carboniferous,it was found that the major controlling factors of favorable weathering volcanic reservoirs were weathering and leaching and reformation of the faults.Reservoir property of different volcanic rocks can be improved by weathering and leaching,forming favorable reservoirs.Secondary dissolved pores and fractures are the main pore types characterized by bimodal distribution.This study also proposed the methods to recognize volcanic weathering mass by using cores and pointed out that various structures of different weathering mass have different pore types and rock textures.Among them,corrosion zone and crumble zone in these layers are favorable reservoirs.Thickness of the volcanic weathering mass can reach to 380 meters.Low angle fractures developed in volcanic weathered mass are controlled by fault,and this thickens the reservoir and improves the reservoir property.Volcanic weathering mass developed mostly in higher position and slope of ancient landscape,especially along faults.Our study revises the old idea that Paleozoic volcanic rock is of strong diagenesis and poor in reservoir property,both of which are unable to form favorable reservoirs,and thus expands domain for oil and gas exploration.The knowledge is of great scientific significance in directing oil and gas exploration in volcanic weathering mass.Our research also indicates that large scale volcanic weathered mass developed in petroliferous basin in the Midwest of China will be a new target for oil and gas exploration in the future.
出处
《地质学报》
EI
CAS
CSCD
北大核心
2011年第4期557-568,共12页
Acta Geologica Sinica
基金
国家科技重大专项(编号2008ZX05001)资助的成果
关键词
新疆北部
三塘湖盆地
火山岩风化体
储集性能
控制因素
northern Xinjiang
Santanghu basin
volcanic weathering mass
reservoir property
controlling factors
