The distribution and geological significance of carbazole compounds in Silurian paleo-pools of the Tarim Basin,Northwest China

The results presented in this paper indicated that the carbazole-type compounds have high thermal stability and also show stability in oxidation and bio-degradation. This kind of compounds still has high concentrations and a complete distribution in the analyzed dry asphalt samples, showing that they are particularly useful in the study of hydrocarbon migration of the paleo-pools. The difference in the contents of nitrogen compounds in the Silurian dry asphalts from the Awati, Tabei and Tazhong areas is attributed to the difference in the extent of oxidation and （or） bio-degradation for the areas; the Awati and Tabei areas underwent relatively strong oxidation and bio-degradation. During the first stage of hydrocarbon pool formation in the Silurian system in the Tazhong and Tabei areas of the Tarim Basin （at the end of the Silurian period） and at the second stage in the Awati area （in Permian）, the hydrocarbons experienced a long-distance migration.     

Petroleum Migration Direction of the Silurian Paleo-pools in the Tarim Basin, Northwest China

The results obtained in this paper indicate that carbazole-type compounds have high thermal stability and also show stability in oxidation and bio-degradation. This kind of compounds still has a high concentration and complete distribution in the analyzed dry asphalt samples, showing that they are particularly useful in studying petroleum migration of paleo-pool. During the basin＇s first-stage of oil-gas pool formation in the Silurian in Tazhong and Tabei areas of Tarim Basin （at the end of Silurian period） and the second-stage in the Awati area （in Permian）, the petroleum experienced a long-distance migration. During the formation of the Silurian paleo-pools in Tazhong Uplift at the end of Silurian, the petroleum mainly came from the lower and middle Cambrian source rocks in the Manjiaer sag. The petroleum migrated towards the southwest-south entering the Silurian reservoir beds in Tazhong first. Then, it further migrated within Silurian from northwest to southeast along the highs of the Structural Belts to the region of the Silurian pinchout boundary in Tazhong. In Tabei Uplift, during the first-stage of pool formation, the petroleum was also from the lower and middle Cambrian source rocks in the Manjiaer sag. It migrated northwest entering the Silurian reservoir beds in the Tabei Uplift firstly, and then the migration continued in the same direction within the Silurian reservoirs and finally the petroleum was trapped in higher positions. During the second-stage pool formation in the Silurian beds in the areas around Awati sag, the petroleum mainly came from the lower-middle Cambrian source rocks in the Awati sag. The petroleum migrated from the generation center to Silurian reservoirs in all directions around the sag through major paths, and the petroleum was finally trapped in higher locations.     

塔里木盆地寒武—奥陶系主要白云岩类型及孔隙发育特征

塔里木盆地寒武系和下奥陶统白云岩广泛发育,岩石类型复杂多样。按照结构和特殊构造两大分类依据,文中将研究区白云岩归为6大类,即泥-粉晶白云岩(又按含膏与否进一步分为含膏泥-粉晶白云岩和不含膏泥-粉晶白云岩)、粉-细晶白云岩、中-粗晶白云岩、斑状白云岩、藻纹层白云岩和膏溶角砾白云岩。每类白云岩都可以其独具特色的晶体结构和/或沉积构造与其他类型相区分。在这些白云岩中发育的孔隙类型主要有6种,即窗格孔、铸模孔、晶间孔、溶孔、角砾孔及砾间溶孔和缝合线孔,其中除窗格孔为原生孔隙外,其余均属次生孔隙。就其储集意义而言,以溶孔和晶间孔最为重要,次为角砾孔及砾间溶孔,而铸模孔和窗格孔的储集意义相对次要。缝合线孔的意义主要有二:一是可改善储集岩的渗透性,二是与斑状白云岩配合还可能构成有效储集岩。     

塔里木盆地孔雀河地区复合含油气系统与有利勘探方向

运用叠合盆地复合含油气系统的描述方法和评价思路,分析了塔里木盆地孔雀河地区含油气系统复合特征,再现从源岩到圈闭的油气地质演化过程。孔雀河地区含油气系统以断裂复合贯通为主,同时存在不整合面复合贯通,构成寒武系C—(!)—下奥陶统O1(!)—石炭系C(*)—三叠系T(*)—侏罗系J(*)+寒武系—C(!)—下奥陶统O1(*)—志留系S(*)—泥盆系D(*)—侏罗系J(*)改造型复合含油气系统(*)。含油气系统的复合经历3个关键时刻:泥盆纪末是构造格局与古油藏形成期,侏罗纪末和白垩纪末是油气转化、重新分配与油藏调整期。研究区可分为破坏散失区、改造调整区、深埋保存区,其中改造调整区、深埋保存区为有利油气聚集区,处在改造调整区的龙口背斜和维马克—开屏背斜的上古生界和中生界的断背斜圈闭以及下古生界残留古断背斜圈闭是最佳勘探目标。     

塔里木盆地塔河地区下石炭统巴楚组沉积演化

以塔里木盆地加里东期和海西两期构造运动为背景,结合现有的岩心、露头、测井、录井和地震资料,对巴楚组可识别出早期的辫状河三角洲沉积,中期的渴湖沉积和盐湖沉积,以及晚期的咸化溻湖沉积。本文分别从横向上和纵向上对塔河地区巴楚组沉积演化进行深入分析;总结了巴楚组构造运动与沉积响应之间的关系,以期为该地区的下石炭统巴楚组的进一步勘探提供科学依据。     

Climatic changes and alluvial-sedimentation settings in southeastern Transbaikalia in the Middle-Late Holocene (by the example of the Ilya floodplain)

Climatic changes in southeastern Transbaikalia in the Middle and Late Holocene and their influence on alluvial sedimentation environments are reconstructed from the results of study of the Ilya floodplain sediments (Alkhanai National Park). At the beginning of the Subboreal period, the regional climate became more arid, which led to a significant increase in steppe species communities in the landscapes. Intense climate aridization also took place at the beginning and at the end of the Subatlantic period of the Holocene. The alluvial-sedimentation rate increased during the weakening of aridization and decreased during cooling and the intensification of aridization. The obtained regional data are compared with data on the adjacent areas and the global climatic changes in the Northern Hemisphere.     

塔里木盆地塔中低凸起地层水化学特征对不整合的响应

对塔中低凸起地层水化学特征与不整合之间关系的研究结果表明,地层水化学特征对不整合具有很好的响应。在遭受强烈抬升和剥蚀、之间形成不整合的奥陶系和志留系,以及紧靠不整合面附近的石炭系CⅢ油组,其地层水具有矿化度、Cl-含量、K Na 含量和r(Cl-Na)/rMg值相对较小,而HCO3-含量、rNa/rCl值和rSO42-×100/rCl值相对较大的特点,反映出地质历史时期大气降水的影响。在志留系与石炭系之间以及志留系与奥陶系之间的不整合面附近,地层水的矿化度、r(Cl-Na)/rMg值和B3 含量变小,而rNa/rCl值和rSO24-×100/rCl值变大,具有典型的遭受大气淋滤的地层水化学基本特征。     

轮南地区奥陶系原油特征及其控制因素

轮南地区油气相态分布非常复杂,奥陶系油气藏平面上具有西油东气的特点。西部轮古西油田、塔河油田和轮南1井区油族成熟度略低且有生物降解痕迹,主要以重油形式分布;东部地区油族成熟度略高,主要以轻质油、凝析油形式存在;中间地段桑塔木断垒带、中部平台区和轮南断垒带发生混合作用形成了中一高蜡油。各地区油气在垂向上变化很大,东部地区奥陶系和石炭系为凝析油气,三叠系又为正常油分布区;西部地区奥陶系为稠油,三叠系为正常油。轮南地区奥陶系在纵向上可能受控于岩溶和储层的发育程度,横向上受控于断裂作用。轮南地区油气成藏时间较早,不同物性的原油都是古油藏多期供油的结果。     

塔里木克拉通东北缘二叠纪镁铁质岩浆氧化物与硫化物成矿条件对比

塔里木克拉通东北缘坡北、磁海等地二叠纪幔源岩浆活动形成了镍钴硫化物矿床和铁钴氧化物矿床，两者赋矿镁铁 超镁铁岩体的年龄相近(290~260 Ma)，主、微量元素和Sr Nd Hf同位素组成相似，分配系数接近的微量元素比值分布于相同趋势线，揭示两者岩浆源区相同，可能为俯冲板片流体交代的亏损地幔或软流圈地幔。两类矿床镁铁 超镁铁质岩中Co与Ni含量正相关，Co主要富集在基性程度高的岩石中；块状硫化物与磁铁矿矿石中Co与Ni相关性差，Co和Ni具有不同的富集机制，Co热液富集作用明显。北山镁铁 超镁铁杂岩体是地幔柱相关软流圈上涌，诱发俯冲板片交代的亏损岩石圈地幔发生部分熔融，形成的高镁母岩浆演化过程中经历壳源混染、硫化物饱和富集镍钴形成铜镍钴硫化物矿床，富铁母岩浆氧逸度高、富水，岩浆分离结晶磁铁矿、叠加热液作用富集钴，形成铁钴氧化物矿床。     

青藏高原东南缘次林错岩体晚白垩世- 早新生代快速剥蚀

青藏高原东南缘是研究构造、地貌演化和气候变化相互作用的理想场所，前人研究主要揭示了晚始新世—早中新世和晚中新世以来的快速剥蚀事件，缺乏晚白垩世—早新生代时期地貌演化过程的研究。次林错花岗岩已有的低温热年代学数据覆盖了整个新生代时期，为探索该区域新生代早期的剥露演化历史提供了重要资料。该岩体新生代早期冷却事件是岩浆冷却单一作用的结果，还是受快速剥蚀作用的影响，目前仍然存疑，需要定量研究。因此，本文结合已有的岩石地化和年代学数据，对次林错花岗岩开展了锆石饱和温度和一维岩浆冷却模拟研究。锆石饱和温度计算结果表明次林错花岗岩的岩浆结晶温度介于647~705℃之间，属低温花岗岩。一维岩浆冷却模拟结果显示岩体侵位时的最小围岩温度为160~120℃，对应深度约为3. 7~5. 0 km。结合锆石和磷灰石(U- Th)/He年代学数据，本文认为该岩体在晚白垩世—早新生代时期(67~40 Ma)经历了一期剥蚀量至少为2 km的快速剥蚀事件。已发表成果的综合分析表明，此次快速剥露事件可能是整个青藏高原地区广泛存在的构造剥蚀事件，新特提斯洋的俯冲闭合与印亚板块的初始碰撞可能是触发此次大规模区域剥蚀的主要原因