摘要
鄂尔多斯盆地二叠系太原组发育一套致密灰岩储层,近年来风险勘探取得重大突破,成为天然气勘探关注的重点领域。通过野外露头、岩心观察、薄片鉴定、扫描电镜和稳定碳、氧同位素等分析测试,开展岩石学、储集空间、储层物性及微观特征研究,系统分析了致密灰岩储层发育特征及有利储层控制因素。研究认为:太原组可作为良好储集层的岩石类型为生屑粉晶灰岩、生屑泥晶灰岩、藻黏结灰岩,储集空间主要为溶孔、残余生物体腔孔、晶间孔及微裂缝,储层平均孔隙度为2.1%,平均渗透率为0.22×10^(-3)μm^(2),属于低孔、低渗储层。太原组灰岩有利储层形成受多种因素控制,其中生屑滩、生物丘有利沉积微相是储层形成的物质基础,决定了储集空间类型及平面大面积分布;高频旋回控制下的准同生岩溶作用有利于溶蚀孔的形成,能有效改善储层的储集性能,为厚层灰岩储层的发育创造了条件;裂缝对改善致密灰岩储层渗流能力具有至关重要的作用。研究成果为鄂尔多斯盆地太原组灰岩的下一步勘探指明了方向,同时,也对华北地台生物碎屑灰岩储层研究及勘探目标优选具有重要借鉴意义。
A set of tight limestone reservoirs has been developed in the Permian Taiyuan Formation of the Ordos Basin.In recent years,the risk exploration has made a substantial breakthrough and has become a key field of natural gas exploration.Through field outcrop,core observation,thin section identification,scanning electron microscope and stable carbon and oxygen isotope analysis and testing,petrology,reservoir space,reservoir physical properties and microscopic characteristics were studied,and the development characteristics of tight limestone reservoirs and controlling factors of favorable reservoirs were systematically analyzed.The research shows that the rock types that can be used as good reservoirs are bioclastic micrite limestone,bioclastic micrite limestone,algal boundstone,and the reservoir space is mainly dissolved pores,residual organism cavity pores,inter-crystalline pores and micro fractures.The average porosity of the reservoir is 2.1%,and the average permeability is 0.22×10^(−3)μm^(2),belonging to low porosity and low permeability reservoirs.The formation of favorable reservoirs of Taiyuan Formation limestone in the study area is controlled by many factors,among which favorable sedimentary microfacies of bioclastic beach and biodome are the material basis for the formation of reservoirs,which determine the type of reservoir space and large plane distribution;Quasisyngenetic karstification under the control of high frequency cycle is favorable for the formation of dissolution holes,effectively improving the reservoir performance,and creating conditions for the development of thick limestone reservoirs;Fractures play an important role in improving the permeability of tight limestone reservoirs.The research results point out the direction for the next step of limestone exploration of Taiyuan Formation in Ordos Basin,and also have important reference significance for the research and exploration of bioclastic limestone reservoirs in North China platform.
作者
董国栋
刘新社
裴文超
付勋勋
曾旭
张道锋
赵小会
DONG Guodong;LIU Xinshe;PEI Wenchao;FU Xunxun;ZENG Xu;ZHANG Daofeng;ZHAO Xiaohui(Exploration and Development Research Institute of PetroChina Changqing Oilfield Company,Xi'an 710018,China;National Engineering Laboratory for Exploration and Development of Low Permeability Oil and Gas Fields,Xi'an 710018,China;Langfang Branch of PetroChina Research Institute of Petroleum Exploration and Development,Langfang 065007,China)
出处
《天然气地球科学》
CAS
CSCD
北大核心
2023年第6期1018-1027,共10页
Natural Gas Geoscience
基金
中国石油天然气股份有限公司科技攻关项目“鄂尔多斯盆地碳酸盐岩重点层系综合地质研究、目标评价、技术攻关与现场试验”(编号:2022KT0103)资助.
关键词
致密灰岩
储层特征
主控因素
太原组
鄂尔多斯盆地
Tight limestone
Reservoir characteristics
Main controlling factors
Taiyuan Formation
Ordos Basin
