塔河油田奥陶系岩溶分带及缝洞结构特征  

Karst zonings and fracture-cave structure characteristics of Ordovician reservoirs in Tahe oilfield,Tarim Basin

作　　者：李阳[1] 金强 钟建华 邹胜章[3] 

机构地区：[1]中国石油化工股份有限公司,北京100728 [2]中国石油大学地球科学与技术学院,山东青岛266580 [3]中国地质科学院岩溶地质研究所,广西桂林541004

出　　处：《石油学报》2016年第3期289-298,共10页Acta Petrolei Sinica

基　　金：国家重点基础研究发展计划(973)项目(2011CB201001)资助

摘　　要：塔河油田是中国发现的储量最大的碳酸盐岩油田,其岩溶储层埋藏深度大、储集空间复杂。通过古今岩溶地质考察,查明了塔北隆起奥陶系岩溶层序中古地貌与岩溶分带及缝洞系统;通过不同岩溶带缝洞成因分析,提出表层岩溶带由地表河、落水洞等缝洞组成,渗流岩溶带缝洞由驻水洞和渗流井组成,径流岩溶带缝洞由厅堂洞、干流洞、支流洞和末梢洞组成;通过岩溶期地表河与地下河沉积、埋藏期垮塌、钙华及热液化学充填作用分析,查明了岩溶缝洞充填特征与缝洞单元的形成。研究结果表明,缝洞系统是由流水溶蚀碳酸盐岩所形成,其始于岩溶高地或岩溶斜坡的落水洞,终于岩溶洼地地下河出水口;一旦缝洞系统部分地被地下河沉积、垮塌和化学充填后,可以形成一个或多个缝洞单元。通过缝洞结构和充填特征分析,认为岩溶期古地貌、潜水面升降和埋藏期的断层活动控制了缝洞单元的形成。研究综合利用地震、测井和地质资料建立缝洞类型和充填物类型识别方法,统一了不同成因类型缝洞的描述术语,为油田开发地质模型的建立提供了详尽的依据。Tahe oilfield is a carbonate oilfield with the largest reserves in China,characterized by large buried depth of karst reservoir and complicated reserving space. Through geological investigations on present and ancient karsts,this study identifies the paleogeomorphic,karst zonings and fracture-cave system in Ordovician karst sequence of the North Tarim uplift. Through an analysis on the geneses of fracture-caves in different karst zonings,it is proposed that the surface karst zoning consists of surface rivers,dolines and other fracture-caves; the fracturecaves in porous flow karst zones are composed of water storage cave and porous flow well,and those in karst runoff zones include hall-like cave,mainstream cave,tributary cave and peripheral cave. The filling characteristics of karst fracture-caves and the formation of fracture-cave units are clarified though analyzing the surface river and subsurface river sedimentation in the karst stage as well as the collapse,travertine and the roles of hydrothermal chemical fillings in the burial stage. The research results indicate that the fracture-cave system is consisted of carbonate rocks dissolved by the running water from the dolines at karst highland or on a karst slope to the outfall of subsurface river at karst depression; if the fracture-cave system partially undergoes subterranean river sedimentation,collapse and chemical fillings,one or more fracture-cave units can be formed. Based on analyzing the fracture-cave structure and filling characteristics,it is believed that the formation of fracture-cave units is controlled by the paleo-geomorphology and phreatic fluctuation in the karst stage as well as the fault activity in the burial stage. In this study,seismic,logging and geological data are comprehensively applied in creating the methods for identification of fracture-cave and filling types,so as to unify the terms describing the fracture-caves with different geneses,thus providing a detailed basis for the establishment of geological model for oilfield developmen

关 键 词：岩溶储层 缝洞系统 缝洞单元 缝洞结构 缝洞充填 塔河油田 

分 类 号：TE122[石油与天然气工程—油气勘探]