摘要
裂缝控制致密油流体渗流方向和注水水窜方向,影响其产量和采收率。为研究长6和长4+5主构造裂缝及衍生的微裂缝方向,同时阐明优势渗流通道方向,以野外露头研究和岩心铸体薄片观察及扫描电镜观测为基础,结合前人研究成果,识别出长6和长4+5油层组三期构造裂缝,走向分别为近南北向、东西向及北东向,同时薄片中可见微观成岩裂缝,包括溶蚀缝、成岩收缩缝及粒内缝。长4+5油层组代表水窜井动态资料研究显示,北东向和东西向为流体优势渗流方向。研究结果表明:(1)南北向裂缝形成最早,受燕山期构造运动控制,北东向裂缝形成最晚,北东向和东西向裂缝受喜山期构造运动控制。(2)研究区构造裂缝规模较大,多条平直缝同时出现,开度值保持固定,具有一定方向性,与非构造成岩裂缝特征差异明显,而宏观构造裂缝与微裂缝之间继承性明显,表现为走向、形态等特征类似,具有相同成因。(3)广泛存在构造裂缝形成北东向和东西向两个高渗水窜通道,该通道上注采井网表现为前期产量较大,后期易水窜。该研究成果为致密油开发中高渗通道研究及井网部署实践提供了指导。
Fractures control the direction of tight oil fluid flow and water channeling for water flooding,and affect its production and recovery.In order to study the main directions of tectonic fractures and derived micro-fractures in Chang 6 and Chang 4+5 reservoirs and direction of their preferential seepage channel,three stages of the tectonic fractures in Chang 6 and Chang 4+5 reservoir groups have been identified based on field outcrop research,core casting thin section observation and scanning electron microscope observation,and previous research results.Their strikes are nearly South-North,East-West,and North-East directions respectively.At the same time,microcosmic diagenetic fractures,including dissolution fractures,diagenetic contraction fractures and intragranular fractures,can be seen in the thin section.The study of representative water channeling wells in Chang 4+5 reservoir groups shows that the fluid flows in the NE and EW mainly.The research re sults show as follows:①fracturesin SN direction formed earliest are controlled by the Yanshanian tectonic movement,the fractures in NE direction form latest,and the fractures in NE and EW direction are controlled by the Himalayan tectonic movement.②Tectonic fractures in the study area are large in scale,flat and straight fractures appear at the same time with fixed opening value in certain directivity,which is obviously different from the characteristics of non-tectonic diagenetic fractures.While the macroscopic tectonic fractures and micro-fractures have obvious inheritance between them showing similar strike,shape and other character istics,and have the same origin.③Tectonic fractures form two main water channeling with high permeability in NE and EW,and the production at early stage is large and water channeling may be easily formed at late stage.The research results provide guidance for high permeability channel research and well pattern deployment in the tight oil development.
作者
张新春
张洪
杨兴利
李相方
Zhang Xinchun;Zhang Hong;Yang Xingli;Li Xiangfang(Dingbian Oil Production Plant,Yanchang Oilfield Co.,Ltd.,Yan′an Shaanxi 716000;State Key Laboratory of Petroleum Resource and Prospecting,China University of Petroleum-Beijing,Beijing 102249;College of Petroleum Engineering,China University of Petroleum-Beijing,Beijing 102249)
出处
《中外能源》
CAS
2021年第10期45-52,共8页
Sino-Global Energy
基金
国家自然科学基金资助项目“页岩油气高效开发基础理论”(编号:51490654)。
关键词
致密油
构造缝
非构造成岩缝
露头
岩心
产能和水窜
tight oil
tectonic fracture
non-tectonic diagenetic fracture
outcrop
core
productivity and water channeling
