准噶尔盆地西北缘二叠系不整合空间结构特征及控藏作用

综合利用露头、测井、录井及岩心资料,对准噶尔盆地二叠系佳木河组顶部不整合进行研究。指出不整合是具有空间结构的地质体,包括正常沉积层、风化粘土层和风化淋滤层。根据各结构层组合的差异,可将该不整合划分为Ⅰ型和Ⅱ型两大类,前者三个结构层发育完整,具有三明治式结构,后者缺失中间的风化粘土层,为双层结构;其中,Ⅰ型不整合在平面上分布广泛,Ⅱ型则主要分布在克百大断裂和佳木河组尖灭线附近。并结合油气勘探成果对各结构层的控藏作用进行分析,认为风化淋滤层和由砂(砾)岩组成的正常沉积层既可作为油气运移的通道,也可作为油气聚集的储集体,但风化淋滤层厚度一般小于300m,且油气最易于富集在100m以上的区域;风化粘土层和正常沉积层中的泥岩是下伏地层油气成藏的封堵条件。     

四川盆地川西北前陆冲断带构造样式及栖霞组成藏模式

利用地震资料,综合构造解剖,提出川西北山前冲断带具有"东西分带、南北分段、上下分层、时间分序、构造分期"的特征,创建了层间逆冲叠瓦构造新样式,构建了新的成藏模式,即以寒武系筇竹寺组为主要烃源岩,以栖霞组台缘滩相白云岩为主要储层,以嘉陵江组膏盐岩为区域性盖层,以逆冲断层相关背斜为主要圈闭,逆冲断层向下断达烃源岩,向上未断...     

库车前陆盆地克拉苏构造带的构造特征与油气

克拉苏构造带位于库车前陆盆地的北侧,由浅部和深部两个层次的构造组成、上、下同层次的构造具有不一致性。浅部层次的构造主要为断层传播褶皱、断层传播－滑脱褶皱,这些构造的突破断层发育,不利于油气的保存;深部层次的构造主要为被动顶板双重构造、突发构造和断层转折褶皱,这些构造在走向上相互转变,构成了本区最有利的构造圈闭。断裂是本区最重要的构造,它不仅是烃源岩排烃的有效机制、而且是油气运移的通道。     

准噶尔盆地构造演化与油气成藏特征

对准噶尔盆地构造特征、地层分布和地层不整合等特征进行的研究结果表明,该盆地内经历了裂陷盆地、碰撞前陆盆地、陆内坳陷盆地和陆内俯冲前陆盆地等4个演化阶段。裂陷盆地控制了石炭系烃源岩,使其沿裂陷槽分布;碰撞前陆盆地将二叠系烃源岩局限于玛湖、昌吉、克拉美丽山等山前坳陷内;陆内坳陷期从三叠纪一直持续到古近纪末,盆地内泥岩和煤岩广泛分布;陆内俯冲前陆盆地发育在南缘西部。因而,古、新近系烃源岩主要分布在安集海—呼图壁一带。烃源岩演化和油源对比表明,盆地内有3次成藏期,分别为印支期(T3)、燕山期(J3)和喜山期(E2),形成了石炭系、二叠系、侏罗系和古近系4个复合含油气系统。根据构造特征和成藏条件的差异性,在盆地内可划分出西北部、西部、南部、东部和腹部5个油气聚集区带。准噶尔盆地的成藏模式主要有逆冲断阶-不整合单向充注、压扭背斜双向充注、断隆带双向充注、披覆背斜单向充注、逆冲背斜带单向充注和斜坡带单向充注6种类型。     

准噶尔盆地西北缘斜坡区不整合面在油气成藏中的作用

准噶尔盆地西北缘斜坡区发育地层不整合油气藏。研究表明,二叠泵内部各组地层之间呈不整合接触,在不整合面附近地层的孔隙度和涌透率明显增大,因而是油气运移的主要通道。玛北油田百口泉、乌尔采组油藏油物性差划与油气运移通道有关,百口泉组油得通过不整合面运移聚集的油气性质以富含轻质组分和低密度为特征。不整合圈闭发育的体是油气聚集的场所,敢富集是在不整合面附近。     

塔里木盆地库车前陆逆冲带异常高压成因及其对油气成藏的影响

在异常高压分布特征的基础上,根据地质特征、构造应力场和物理模拟实验研究,对库车前陆逆冲带异常高压的成因机理进行了探讨,并对异常高压对油气成藏的影响进行了分析.库车前陆逆冲带的异常压力从古近系底开始出现,在侏罗系和三叠系也明显存在,但其压力系数低于古近系底部-白垩系压力系统.在平面上,异常压力呈东西向带状分布,中部克拉苏-东秋-迪那构造带的地层压力系数最大,往两侧递减.异常高压的形成主要与早更新世强烈的构造挤压作用有关,构造抬升作用、欠压实作用和流体充注作用对异常高压的贡献较小.在早更新世快速、强烈的构造挤压作用下,岩石的格架首先承担了1/4的构造挤压应力,其余由孔隙流体来承担,在古近系膏盐层良好的封闭作用下,使得岩石的孔隙流体压力快速上升,从而形成了库车前陆逆冲带的异常高压.异常高压对油气成藏具有重要的影响,它是形成库车前陆逆冲带大型油气田的必要条件.     

准噶尔盆地北缘山前带湿地扇沉积特征及控藏作用

综合野外露头、岩心、钻测井以及分析测试资料等,对准噶尔盆地北缘哈拉阿拉特山山前带侏罗系八道湾组开展了系统的沉积相研究。结果表明:八道湾组一段沉积时期,受构造背景、古物源、古气候的综合影响,哈山南缘山前带发育一套典型的湿地扇沉积,可识别出扇根、扇中、扇缘三种亚相,扇中可进一步分为辫状水道和泥炭沼泽两类微相;在明确了相类型及其展布特征的基础上,建立研究区湿地扇沉积相模式,其在岩性特征、沉积序列、平面规模、微相组合等方面均与洪积扇有明显区别;山前带湿地扇沉积区具有良好的勘探潜力,有利的微相、岩石相以及原始沉积组构共同控制着油藏分布,其中扇中辫状水道砂砾岩相和粗砂岩相为原油富集的有利储集相带。     

塔里木盆地克深前陆冲断带储层岩石力学参数研究

综合采用岩石单轴压缩试验、三轴压缩试验及测井资料计算,对塔里木盆地克深前陆冲断带单井的岩石力学参数进行分析,通过单轴-三轴校正及动态-静态校正,确定静态岩石力学参数的单井剖面,利用高斯插值对岩石力学参数空间分布特征进行研究,并分析岩石力学参数与地层深度的关系。结果表明:岩石力学参数的空间分布主要与岩相有关,并在一定程度上反映了储层物性特征,弹性模量、内聚力和抗压强度大而泊松比小的区域储层物性相对更好;随着地层深度的增加,弹性模量、内聚力和抗压强度逐渐增加而泊松比逐渐下降;利用岩石力学参数与地层深度的关系以及断层带岩石力学参数的经验比例,可以对不同地质单元的岩石力学参数进行取值,为后续的地应力场及储层裂缝数值模拟奠定基础。     

龙门山南段前陆冲断带内的古油气藏

通过对龙门山南段地表沥青发育特征及分布规律的研究,对比不同层位中流体充注特征,结合该地区构造演化史,证实了龙门山南段冲断带内曾经存在过古油(气)藏,重塑了古油(气)藏形成和破坏的过程.研究表明,沥青主要分布于观雾山组和灯影组次生溶孔、溶洞和裂缝中;以灯影组中沥青最为发育,侧向延伸稳定,垂向充填较厚,说明研究区曾存在过古油(气)藏.晚三叠世以前,来源于松潘一甘孜海盆的油藏流体,由西向东运移充注于现今前陆冲断带内的震旦系灯影组、泥盆系和二叠系储集空间中形成古油藏;晚三叠世盆山转换时期,古油藏随着前陆盆地的快速沉降而被深埋,油裂解成气而形成古气藏;随着冲断带向前陆盆地扩展,赋存于前陆盆地内的古气藏被     

冀中坳陷鄚州变换带演化特征及控藏作用

通过高精度三维地震解释、钻井、岩心、薄片和测井等资料分析,结合凹陷主干边界断裂及鄚州构造带内部断裂特征解析,对鄚州变换带构造属性及其控藏作用进行研究。结果表明:鄚州构造带在古近纪具有调节区域构造变形的作用,变换带历经弧形断裂系-扁豆状断块形成期、雁列状断裂系-堑垒状断块形成期和雁列状断裂系-塌陷背斜形成期3个独特的演化阶段;变换带不仅改善潜山碳酸盐岩储层物性,而且控制了古近系碎屑岩储层的展布;古近系烃源岩与变换带油气成藏相关的地质因素及地质作用具有良好的时空配置关系,形成新生古储型和自生自储自盖型两种油气聚集模式。     

准噶尔盆地西北缘乌夏断裂带构造特征与油气成藏模式

在分析准噶尔盆地乌夏地区构造特征、沉积类型和成藏过程的基础上,以油气源、油气运移方向、运移过程和成藏期等因素为背景,将研究区的成藏模式划分为近源侧向砂体-不整合输导早期成藏模式、近源垂向断层输导多期成藏模式、远源混向"Z"字型输导多期成藏模式和远源混向阶梯状输导晚期成藏模式4种类型.乌夏断裂带构造活动的复杂性导致油气成藏具有明显的分段性、多期次和多类型的成藏特点.研究认为,断裂发育和不整合面是形成不同油气藏模式的主要控制因素.     

Mechanisms of abnormal overpressure generation in Kuqa foreland thrust belt and their impacts on oil and gas reservoir formation

 Based on overview for mechanism of abnormaloverpressure generation in sedimentary basins, an insightdiscussion is made by the authors for the distribution, fea-tures and generation mechanisms of abnormal overpressurein the Kuqa foreland thrust belt. The abnormal overpressurein the Kelasu structure zone west to the Kuqa forelandthrust belt was primarily distributed in Eogene to lowerCretaceous formations; structural compression and struc-tural emplacement as well as the containment of Eogenegyps-salt formation constituted the main mechanisms for thegeneration of abnormal overpressure. The abnormal over-pressure zone in the eastern Yiqikelike structure zone wasdistributed primarily in lower Jurassic Ahe Group, resultingfrom hydrocarbon generation as well as structural stressother than from under-compaction. Various distributionsand generating mechanisms have different impacts upon theformation of oil and gas reservoirs. K-E reservoir in the Ke-lasu zone is an allochthonous abnormal overpressure system.One of the conditions for reservoir accumulation is the mi-gration of hydrocarbon (T-J hydrocarbon source rock) alongthe fault up to K-E reservoir and accumulated into reservoir.And this migration process was controlled by the abnormaloverpressure system in K-E reservoir. The confined abnor-mal overpressure system in the Yiqikelike structure zoneconstituted the main cause for the poor developing of dis-solved porosity in T-J reservoir, resulting in poor physicalproperty of reservoir. The poor physical property of T-J res-ervoir of Yinan 2 structure was the main cause for the ab-sence of oil accumulation, but the presence of natural gasreservoir in the structure.     

Abnormal high pressure in Kuqa foreland thrust belt of Tarim basin: Origin and impacts on hydrocarbon accumulation

Following analyses of the abnormal high pressure distribution characteristics, based on the geological characteristics, tectonic stress field and physical simulation, we investigated the formation mechanisms of abnormal high pressure and its impacts on hydrocarbon accumulation in the Kuqa foreland thrust belt. The abnormal high pressure appears at the bottom of the Paleogene and obviously exists in the Triassic and Jurassic. However, the pressure coefficient in the Triassic and Jurassic is lower than that in the Cretaceous and at the bottom of the Paleogene. Horizontally, the abnormal high pressure distribution is characterized by E-W orientation zoning. The maximum pressure coefficient lies in the Kelasu-Dongqiu-Dina tectonic zones in the center of the Kuqa foreland thrust belt and decreases away from the tectonic zones. The formation of abnormal high pressure was mainly related with the intense tectonic compression in the Early Pleistocene time, and tectonic uplifting, undercompaction and hydrocarbon generation were secondary factors contributing to abnormal high pressure. Under the rapid and intense tectonic compression in the Early Pleistocene, the rock framework firstly undertook 1/4 of the compression stress and the other was borne by the pore fluids. Due to the presence of great seal of gypsum-salt or gypsum-mudstone beds in the Paleogene, the pressure of pore fluids increased rapidly and led to the abnormal high pressure in the Kuqa foreland thrust belt. The abnormal high pressure has important impacts on hydrocarbon accumulation. It is one of the necessary conditions for formation of large oil and gas fields in the Kuqa foreland thrust belt.     

Controlling factors for large gas field formation in thrust belt of Kuqa coal derived hydrocarbon foreland basin

 Kuqa depression is a foreland basin developedwith Mesozoic-Triassic-Jurassic coal-bearing formation. Theresearch results of the coal-derived hydrocarbon forelandbasins in Kuqa depression indicated that the coal-bearingformation can be the rich sources for generating gas becauseof their thickness and rich source rocks with gas-generatingpredominant kerogen. Although the foreland thrust beltmainly acting in compression is very complicated, integrallarge structural traps can be formed. Moreover, the thrustbelt can act as the passage for communication with deepsource rocks. The high quality gypsolish and gypseous mud-stone cap rock developed in the upper formation is the keyfor the formation of the large gas field. The late formation ofreservoirs in the large gas fields depended on the hydrocar-bon-generating history controlled by the foreland basin andthe developing process of foreland thrust belt.     

库车坳陷克拉苏冲断带传递型超压的识别、计算及其主控因素

超压可在断裂的沟通作用下发生垂向传递,目前对于断裂传递型超压的识别、计算和预测研究还比较薄弱。分析此类超压的成因,修正前人关于垂向传递型超压识别方法,以库车坳陷克拉苏冲断带盐下断裂发育的超压地层为例,通过含气声速校正和浮力校正,识别盐下断裂传递型超压,近似计算传递量,最终分析影响该区断裂传递超压量的主控因素。结果表明:克拉苏冲断带的大北和克拉苏地区的盐下地层均不同程度存在超压传递现象;超压的传递量在大北地区大北3井为24.10 MPa,在吐北2井为26.35 MPa,克拉苏地区的克拉2井平均为16.47 MPa,由断裂传递所产生的超压约占实测总过剩压力的50%;超压的传递量主要受断裂的断距、倾角及断裂穿越地层的过剩压力梯度的综合影响,是三者乘积的综合效应。     

吐鲁番坳陷逆掩断裂带下盘油气勘探领域成藏条件

以吐哈盆地区域构造应力场分析和以轴面成图与构造趋势分析为基础的吐鲁番坳陷3维空间构造演化模拟为出发点,认为吐鲁番坳陷侏罗系发育3排弧形构造带组成的巨型弧形构造体系,提出吐鲁番富油气坳陷发育逆掩断裂带下盘油气勘探新领域.逆掩断裂带下盘油气勘探领域有利成藏条件主要表现在:发育构造、岩性2大类和背斜、断鼻、断块、顺物源岩性和反物源岩性5种类型圈闭,构造类圈闭主要形成于侏罗系末期,岩性类圈闭主要依附于古构造背景发育,剩余圈闭面积大且成群成带分布,整体勘探程度较低,勘探潜力较大;紧邻3大主力生烃凹陷(胜北、丘东和小草湖),油源条件优越;发育中侏罗统区域和中下侏罗统局部2套盖层,逆掩断裂带下盘上倾方向断裂封堵条件好,后期保存条件优越,有利于较低部位的油气聚集成藏;整体构造体系与圈闭主要形成于侏罗系末期到白垩系早期,与侏罗系末白垩系的油气生成、运移与聚集期匹配良好,是吐哈盆地侏罗系进一步勘探的主要领域.