Basement strike-slip fault zones of petroliferous basins are newly recognized high-yield hydrocarbon enrichment zones with broad prospects for oil/gas exploration and development. Increasingly more attention has been paid to the identification and geometrical/kinematical characterization of basement strike-slip faults as well as the role of “reservoir/pool controls” in this type of fault systems. This paper reports the new discovery of large-scale NW and NE-trending basement strike-slip fault zones in Fuling area, eastern Sichuan Basin, and establishes the identification criteria for strike-slip faults in this area based on characteristic fault patterns. The characteristic fault patterns include vertical faults and flower-like structures on the profile; planar linear extension of fault with staggered geological boundaries; and obvious segmentation of master faults in “ribbon-like” or “dolphin-like” strike-slip fault patterns and with changing mechanical properties. A new method is proposed for determining the strike-slip directions based on seismic analysis to measure the change of vertical displacements and the difference in tectonic-activity intensities between the two sides of the fault. It is found that the NW-trending basement strike-slip fault zone generally presents left-lateral slip but with variable strike-slip deformations in different evolutionary stages. Since its formation, the NW-trending faults zone has experienced at least 5 left-lateral and 3 right-lateral slip events which can be characterized by left-lateral slip in the deep crust, right-lateral slip in the shallow crust, high activity-intensity in the north and low activity-intensity in the south, with a cumulative left-lateral strike-slip offset reaching up to 1400-3400 m. In comparison, the NE-trending basement strike-slip fault zone is characterized by right-lateral strike-slip, and the cumulative strike-slip offset is about 1930 m. It suggests that there are significant differences in the formation and evolution of the two fault zones controlled mainly by regional tectonic movements, evolution of stress field environment in different evolutionary stages as well as stress release of regional detachment layers where the NW-trending strike-slip fault zone is affected by Lower-Triassic gypsum-salt detachment layer and the NE-trending strike-slip zone is affected by Middle-Lower-Silurian shale detachment layer.

The eastern Sichuan Basin has undergone multiple stages of tectonic evolution and shows complex structural characteristics. It is found that there are a series of NW-SE base-trending strike-slip faults in this area besides NE-SW strike-blocking structures. There are almost no previous studies on strike-slip faults in the eastern Sichuan Basin. This paper fills in the blank of geometry and kinematics research on the strike-slip fault zone in this area. Based on highly precise 3D seismic section, coherent attribute slice and time slice, the geometric and kinematic characteristics of the fault are analyzed. The dynamic characteristics are analysed based on the structural style of the superimposed development model and the nature and activity intensity of strike-slip faults in different periods. and it was found that No. 15 strike-slip fault was a large basement strike-slip fault. The research results show that the profile of the No. 15 strike-slip fault mainly shows a subvertical fracture, positive flower structure and negative flower structure and a composite flower structure with positive and negative flower structures superimposed on each other in the upper and lower planar sections with linearly outspread and zonal distribution characteristics; spatially, there is a “ribbon” effect and a “dolphin” effect. the left strike-slip distance of the TS interface is 0.462 km, and the right strike-slip distance of the TP2 interface is 0.782 km. The strike-slip fault experienced at least three active stages of superimposed deformation during its formation and reconstruction, among which episode II in the middle Caledonian movement was the main active stage of the No. 15 strike-slip fault zone. This study of the structural style and genetic mechanism of a strike-slip fault zone is of guiding significance to the exploration and development of strike-slip fault-controlled reservoirs in the study area.

针对热液白云岩展布非均质性强的问题,开展基底断裂与茅三段沉积演化关系研究,分析断裂样式与白云岩分布关系,建立沉积演化模式,预测白云岩的分布.研究结果表明:茅三段可划分为5个小层,1～3小层为白云岩发育主要时期,4～5小层为台地均一化时期,不发育白云岩;15-1、15-2和16号基底断裂控制了早期"台-洼"相间的沉积地貌,断裂附近的地貌高部位为生屑滩发育有利部位,为白云岩的发育提供物质基础;15-1、15-2号基底断裂样式为花状,周边生屑滩白云石化程度高,为白云岩发育最有利区;16号基底断裂为直立状,附近白云石化发育程度较低,为白云岩发育较有利区.研究成果可为热液白云岩领域的进一步勘探提供指导依据.

近期川东南及邻区钻井揭示东吴期断控岩溶储层具有良好的规模勘探潜力,因此,本文利用川东南LZ地区三维地震资料及邻区钻井资料,分析了研究区走滑断裂特征与形成演化及其对天然气成藏的意义.结果表明:①研究区走滑断裂剖面上发育"Y"字形、花状构造、直立状3种构造样式.②走滑断裂形成于东吴期,晚燕山期以来挤压活化.③走滑断裂一方面控制下二叠统岩溶储集层的形成与分布,另一方面作为垂向运移通道沟通志留系烃源有利于茅口组岩溶储层油气成藏.

为了明确川东南涪陵地区茅口组热液白云岩气藏富集规律,基于钻井、岩心和涪陵地区连片三维地震资料,分析了研究区基底断裂特征与形成演化及其对茅口组油气成藏的意义,建立了油气成藏模式.研究结果表明:研究区基底断裂剖面上发育"Y"字形与反"Y"字形、"花状"、直立状3种构造样式;平面上识别出15、15-1、16号3条基底断裂,均以北西—南东向展布为主;基底断裂纵向上具有分层特征,同时沿断裂走向又体现出分段差异性;15、15-1号基底断裂中、上构造层活动性强于16号基底断裂,15号基底断裂西段活动性强于中段和东段.基底断裂控制了茅口组油气藏的形成与分布;白云岩储层沿基底断裂两侧呈条带状展布,距基底断裂越近,下伏志留系烃源岩对茅口组成藏贡献越大,含气性越好,测试产量越高.综合研究区基底断裂、烃源岩和储层发育特征等,建立了"下生上储、双源供烃"油气成藏模式.研究成果对深化涪陵地区茅口组热液白云岩研究具有重要指导意义,同时可为其他基底断裂发育区油气成藏研究提供借鉴.

为进一步落实四川盆地元坝地区上二叠统长兴组—下三叠统飞仙关组超深层海相礁滩大气田沉积相带及储集层发育特征,通过井震互馈建立了高精度等时层序地层格架,并揭示沉积相带展布和储集层发育明显与层序地层格架密切相关.在此基础上,开展了针对台缘礁滩带的沉积相敏感性属性提取、反演及沉积相对应性分析,系统刻画了礁滩体的生长特征.钻井验证分析揭示,依据高精度层序地层格架预测的礁滩储集层发育特征与钻井揭示的情况吻合度高,有效地解释了多口井在礁滩发育相带试获超百万方高产工业气流的原因.刻画了元坝气田陆棚相、台缘斜坡相、台缘相、开阔台地相、局限台地相,及次级相包括生屑滩、台缘礁滩、台缘生物礁、鲕粒滩和滩间海的平面展布特征,为元坝地区勘探开发一体化建设奠定了良好的基础.

利用地震、地质资料,系统分析了川东南涪陵地区印支期至今构造演化特征及其对油气聚集的控制作用.研究认为涪陵地区印支期—燕山早期构造抬升呈现南北高,中部低的鞍状特点、晚燕山期开始挤压,至喜山期挤压作用最活跃.结合涪陵地区沉积埋藏史,认为海相上组合各层系油气成藏受构造作用控制,整体经历了印支期—燕山早期古油藏形成、燕山中晚期古气藏发育和喜山期气藏调整改造的过程,但不同层位不同圈闭类型受构造控制作用不同.

On the basis of the seismic data and geological information,we analyzed the tectonic characteristics, evolution and formation mechanism of high and steep structures in eastern Sichuan.The high and steep fault folding belt experienced the dynamic environment change from extension to compression,and is divided into four tectonic evolution stages:the formation of incompetent folding (The Indosinian before), the formation of embryonic folding (The Indosinian period ), the formation of active folding (The Yanshanian period ),the formation of fold forming (The Himalayan period ).The present tectonic framework of high and steep fault folding belt in eastern Sichuan is controlled by pre-existing structures, and multiple stages of compression tectonic superimposition,finally resulted in the formation of high and steep fault folding belt with is ejective structure.Influenced by two sets of gypsum-salt detachment layer and one set of shale detachment layer,the high and steep fault folding belt in eastern Sichuan can be divided into three tectonic deformation layers.During the multiple stages of extrusion stress,each structural layer shows various structures evolution due to the differences in the longitudinal formation and evoluation.There is some guiding significance to the further study on the control of the multi-phase tectonic superimposition on the salt deposits and the oil and gas preservation.

从綦江及邻区须家河组地层特征、沉积特征、储层特征及烃源岩特征等方面,分析了须家河组含油气地质条件及勘探潜力.研究表明:①綦江地区上三叠统须家河组发育辫状河三角洲平原沉积,岩性组合具有“砂包泥”的特点,整体上辫状河道砂体发育,具备形成规模储层的基础;②储层岩石致密-超致密,为特低孔、特低渗储层,裂缝和次生溶孔是储层发育的关键;③通过寻找相对低砂地比层系,叠合深大断裂沟通的须家河组构造,寻找混合气源的构造-岩性油气藏;④有深大断裂沟通深部海相气源的须家河组构造是有利的勘探目标.