油气输导体系研究现状及存在问题的探讨

油气输导体系是油气成藏体系的必要元素,也是油气运移研究的薄弱环节。人们对于这一概念的阐述各不相同,绝大多数学者将其划分为高孔渗砂体、断层及裂缝、不整合面以及它们两两或全部的复合输导体系四种类型,目前对输导体系的研究也集中在这四种类型上。对高孔渗砂体的研究主要集中在孔隙结构、渗透率和优势运移通道上;对断层的研究主要集中在断层泥、非渗透性物质、两盘特征、断层面应力及断层活动性上;对不整合面的研究主要集中在其产状、性质、类型及岩性组合等方面。输导体系的类型划分应当以渗透率非均质性为依据,同时充分考虑烃源岩。从盆地沉积演化的角度出发研究各类输导体系的分布,也是油气运移研究领域中的薄弱环节。     

含有不整合面的钻井剖面中酸解烃的垂向分布规律

系统测量了不同时代、不同埋深的不整合面钻井剖面中酸解烃的分布,发现不整合面之下发育有总烃、甲烷浓度低而大分子烃类相对富集的烃类异常带,分析认为此异常带是风化脱气作用形成的脱气带,其厚度与下伏地层成岩程度有关。该发现对评价含油气盆地剥蚀与气藏保存、破坏的关系,不整合面对油气运聚的影响等有重要意义,也为解决剥蚀量恢复问题提供了新的科学线索。     

Linear and angular momentum conservation in hydraulic jump in diverging channels

This paper addresses the integral conservation of linear and angular momentum in the steady hydraulic jump in a linearly diverging channel.The flow is considered to be divided into a mainstream that conveys the total liquid discharge, and a roller where no average mass transport occurs. It is assumed that no macroscopic rheological relationship holds, so mass, momentum and angular momentum integral balances are independent relationships. Normal stresses are assumed to be hydrostatic on vertical, cylindrical surfaces. Viscous stresses are assumed to be negligible with respect to turbulent stresses. Assuming that the horizontal velocity distribution in the mainstream is uniform and that the horizontal momentum and angular momentum in the roller are negligible with respect to their mainstream counterparts, an analytical solution is obtained for the free surface profile of the flow. This solution is fundamental for finding the sequent depths and their positions. Consequently, it permits solving for the length of the jump, which is assumed to be equal to the length of the roller. Mainstream and roller thicknesses can also be derived from the present solution. This model may also be theoretically used to derive the average shear stresses exerted by the roller on the mainstream and the power losses per unit weight. This second relationship, which returns the well-known classical expression for total power loss in the jump, demonstrates that the strongly idealized mechanical model proposed here is internally consistent.     

东吴运动的沉积学响应——以湘鄂西及邻区二叠系茅口组顶部不整合面为例

湘鄂西及邻区二叠系茅口组顶部广泛发育了岩溶角砾岩,并形成了一个分布范围广阔的不整合面,该不整合面特征在各地存在明显差异,其上覆孤峰组与龙潭组也存在不同程度的缺失。东吴运动为两幕式构造运动,上述现象正是东吴运动Ⅰ幕、Ⅱ幕在不同地区的沉积学响应。     

阿尔金山东段恰什坎萨依沟的地层新发现

出露于阿尔金山北坡的这套厚度巨大、基本不变质的海相沉积地层,岩性以火山岩、碎屑岩、碳酸盐岩为主,在恰什坎萨依沟的实测剖面中发现该套地层不整合于一套中深变质的长城系之上,不整合以上的硅质岩中发现放射虫、海绵骨针等化石,放射虫化石经鉴定,年代为奥陶纪中晚期,根据以上新发现对本地区的该套地层进行了重新划分与厘定。     

Palaeosols and palaeokarst beneath subaerial unconformities in an Upper Devonian isolated reef complex (Judy Creek), Swan Hills Formation,west‐central Alberta,Canada

Subaerial unconformities are used widely for palaeoenvironmental and palaeogeographic reconstructions, sequence stratigraphy and petroleum reservoir assessments. Recognition and interpretation of these unconformities, particularly those with associated palaeosols, may be problematic in Lower and Middle Palaeozoic carbonate successions because of the collective effect of limited land plant development, superficial similarities between some pedogenic and marine features, and overprinting by later diagenesis. The isolated Judy Creek reef complex in the Lower Frasnian Swan Hills Formation in west‐central Alberta, Canada, contains two subaerial unconformities, R0.5 and R4, which formed as a consequence of relative sea‐level falls of at least regional scale. Deposits beneath these unconformities have distinctive palaeosol and palaeokarst features. The lower unconformity, R0.5, occurs at the top of a progradational reefal phase of stromatoporoid rudstones–floatstones and peloidal packstones–grainstones and has been recognized in at least one other isolated Swan Hills reef complex (Snipe Lake). Palaeosol–palaeokarst profiles beneath this unconformity extend as deep as ca 2 m below the unconformity. These profiles are characterized by the presence of small rhizoliths, laminar calcretes, ferroan dolomite glaebules, desiccation cracks, breccias, green shale and solution vugs. The upper unconformity, R4, occurs at the top of a backstepping phase of reef growth and has been correlated widely between isolated reefs and carbonate banks on both the western and eastern shelves of the Central Alberta Basin. Palaeosol–palaeokarst profiles, extending as deep as ca 9·5 m beneath the R4 unconformity, are distinguished by abundant, sub‐horizontal desiccation cracks filled with green shale, occurring in peloidal wackestones–packstones. Comparison of the R0.5 and R4 profiles indicates that the major intrinsic controls on the development and modification of the profiles are parent‐material lithology, particularly the prior degree of induration and particle size; the low topographic relief at the top of the reef interior; and limited vegetation of the exposed reef top due to unfavourable growth conditions and geographic isolation. In addition to climate, the major extrinsic controls are the extent of relative sea‐level fall, estimated to be 2·5 to 3 m and 13 to 14 m associated with the R0.5 and R4 unconformities, respectively, and the degree of shoreface erosion during the ensuing marine transgression, estimated to be up to 3 m. This study highlights the complex interplay of mainly physical and chemical processes influencing the formation of subaerial unconformities in carbonate environments during the Devonian, before major evolutionary innovations among vascular land plants led to more intense pedogenesis.     

五台山地区古元古界滹沱群沉积环境:前陆盆地还是陆内裂谷盆地?

分布于五台山地区的古元古界滹沱群形成的大地构造环境和地质演化过程,对华北克拉通东、西部陆块之间的华北中部碰撞造山带的形成时代和演化具有关键性的地质约束.通过对滹沱群与下伏地质体之间的接触关系、滹沱群沉积岩石序列组合特征、构造变形样式和已有同位素年代学资料的综合分析,认为(1)滹沱群呈区域性角度不整合覆盖于新太古代五台群...     

冀中坳陷潜山油气输导体系及与油气藏类型的匹配关系

通过总结前人研究结果,利用测井、钻井地质和地化等资料,对冀中坳陷潜山油气藏类型和油气输导体系特征进行研究,并结合已发现的潜山油气藏,建立了不同油气输导体系与潜山油气藏类型的匹配关系。结果表明:根据不同的圈闭遮挡条件,可将冀中坳陷潜山油气藏分为潜山顶、潜山坡和潜山内幕油气藏等3种类型;潜山油气输导体系发育断裂、不整合、内幕溶蚀层和复合型输导体系等4种类型;受碳酸盐岩地层、断层活动性影响以及与油气生成时间的匹配,断裂型输导体系具有高效性和时效性的特征,有利于形成潜山顶和内幕油气藏;不整合型输导体系由不整合上部底砾岩和下部淋浴带组成,具有"双层"输导的特点,有利于形成潜山顶和潜山坡油气藏;内幕溶蚀层型输导体系由潜山内部的溶蚀孔-洞-缝系统组成,其发育程度受内部地层泥质含量控制,有利于形成潜山内幕油气藏;复合型输导体系由单一型输导体系复合形成,具有"多样式"的特点,可以形成潜山顶、潜山坡和潜山内幕油气藏。     

地层不整合遮挡油气藏地质储量计算新方法及其应用

从几何学的观点出发,针对纯油藏和具有气顶的油气藏,采用单储系数、横截面面积与油层横向分布长度三者乘积的方式改进采用单储系数、含油面积与油层厚度三者乘积方式的传统容积法,提出相应的地层不整合遮挡油气藏地质储量计算新公式,并根据油气藏的特点提出水平井钻遇油气藏厚度的预测公式。地层不整合遮挡油气藏的地质储量计算目前主要采用容积法,这类方法不仅计算繁琐,而且不确定因素较多;改进后的新方法计算简单方便,理论性更强,存在的不确定因素显著减少。采用新方法在高青油田高424块高424-1井区进行了实践应用。实践表明:改进的新方法适用于地层不整合遮挡油气藏的地质储量计算及预测水平井钻遇油气藏厚度。     

内蒙古乌斯尼黑蛇绿混杂岩带形成时代的地质新证据

贺根山-乌斯尼黑蛇绿混杂岩带的属性和形成时代存在明显的认识上的分歧.早期认为是二叠纪侵入的超镁铁质岩体.该超镁铁质岩体侵入了下二叠统格根敖包组,并被哲斯组地层不整合覆盖,形成时代为二叠纪.20世纪80年代以来,通过中国北方板块构造研究,在硅质岩中采集到的一系列化石资料表明,贺根山地区蛇绿混杂岩的形成时代应为中-晚泥盆世...