唐古拉山地区三叠纪层序地层分析及构造演化

三叠纪充填的一套碳酸盐岩—碎屑岩地层,被划分为两个超层序和5个层序单元。超层序Ⅰ以复理石建造为特征,是金沙江缝合带初始碰撞作用的产物,是唐古拉山地区三叠纪前陆盆地早期挠曲沉降构造活动的沉积响应,标志着晚三叠世诺利期前陆盆地业已形成;超层序Ⅱ以磨拉石与酸性火山岩建造为特征,是前陆盆地晚期冲断抬升构造演化的沉积响应,表明晚三叠世瑞替期来自造山带的沉积物开始越过前陆隆起向隆后盆地迁移。     

准噶尔永进地区深部储层的保存与发育机理

随着油气勘探向深部发展,在深部寻找优质储层是一个亟待深入研究的问题。永进地区位于准噶尔腹部中石化中部3区块,勘探目的层埋藏深,大于5000m,储层多为低孔-特低孔低渗-特低渗储层,因此,在该地区深部寻找相对优质储层具有重要的理论意义和勘探意义。该地区发育区域性不整合,即J/K不整合。在不整合形成期间,大气淡水具有高的流速和相对开放的流体环境,可以溶蚀易溶矿物并将溶蚀产物带离出溶蚀区;颗粒包壳可以抑制石英加大和碳酸盐矿物沉淀,保存原生孔隙和形成的次生孔隙;永进地区油气充注早,早期的油气充注改善了流体成岩环境,抑制胶结作用,同时,其携带的有机酸溶蚀易溶矿物,产生次生孔隙,油气早期充注从两个方面改善储层。     

鄂尔多斯盆地中新生代峰值年龄事件及其沉积-构造响应

通过锆石-磷灰石裂变径迹年龄分布及其与粗碎屑沉积建造和地层不整合关系的综合分析,提供了鄂尔多斯盆地中新生代构造事件的年代学约束及其沉积响应特点。印支期构造事件主要发生在230～190Ma,包含215Ma和195Ma两个峰值年龄,在盆地西南缘发育晚三叠世粗碎屑类磨拉石建造及其与上覆地层的平行不整合。燕山期构造事件主要发生在燕山中晚期的150～85Ma,包含145Ma、120Ma和95Ma等3个峰值年龄,在盆地西南缘发育燕山中期的晚侏罗世和早白垩世的粗碎屑类磨拉石建造及其地层间的角度不整合。喜山期构造事件主要表现为盆地区域的多旋回构造隆升,至少包含55Ma、25Ma和5Ma等3个幕次的峰值年龄事件。其中,锆石和磷灰石叠合分布的峰值年龄(145Ma)和其相关的角度不整合、逆冲推覆和区域岩浆活动等,共同指示了鄂尔多斯盆地中新生代的一次关键构造变革事件。     

鄂尔多斯盆地能源矿产氯仿沥青Sm-Nd同位素研究

对鄂尔多斯盆地石油、煤、含铀砂岩及其围岩的氯仿沥青进行了Sm-Nd同位素研究。结果表明,盆地流体(包括深部流体)活动具有多期性,且后期的流体活动对铀矿床的形成具有重要作用;赋存于同一套地层中的含铀砂岩沥青、煤沥青及石油沥青,虽然均具有富集地幔特征,但并非同期活动的产物;东胜矿区侏罗系直罗组煤沥青和盆地西南部陈家山矿区侏罗系延安组的煤沥青,源区时代上存在较大差异,伴生沥青并非全部由煤的热演化形成,可能还存在外来流体的加入,且东胜直罗组煤的伴生沥青较延安组煤的伴生沥青来源深度更大;盆地内马岭油田的直罗组石油沥青、陈家山延安组煤层石油沥青及其煤沥青在源区特征上具有内在联系。     

构造强烈改造型盆地——来自杉松岗盆地的证据

通过对杉松岗盆地构造变形的研究与分析,总结并提出构造强烈改造型盆地的概念。构造强烈改造型盆地主要特征表现为盆地的原生状态遭到毁灭性的破坏,盆地的现存岩貌是构造改造的结果而非原始的有序堆积;各种构造岩和构造煤的广泛发育是构造强烈改造型盆地的重要物质记录;混杂堆积构成的宏观有序、微观无序的叠堆构造是构造强烈改造型盆地的主要控煤构造。     

鄂北杭锦旗地区下石盒子组储层物性特征及评价

杭锦旗地区位于鄂尔多斯盆地北部伊盟隆起杭锦旗断阶带上,下石盒子组为辫状河和河流相沉积。通过薄片观察、岩心物性分析和压汞曲线实验,对岩石学特征、物性特征、孔隙结构特征进行了分析。结果表明:下石盒子组砂岩储层孔隙类型,主要有剩余原生粒间孔、次生孔隙和高岭石晶间隙;裂缝不发育;孔隙结构可分为细喉微孔型、粗喉大孔型和细喉中孔型三类,其中以细喉中孔型为主。储层为中低孔、低渗储层,盒3段物性最好。利用径向基神经网络解释的孔隙度参数在岩心实验校正后进行储层平面分布评价,结果表明:锦2、锦6～锦7井区是下石盒子组有利发育带。     

鄂尔多斯北部直罗组中烃类包裹体地球化学特征及来源分析

对鄂尔多斯盆地东胜地区中侏罗统直罗组砂岩中烃类包裹体进行镜下观察、描述，利用压碎抽提法对烃类包裹体进行色谱—质谱分析，并与白垩系油苗、三叠系油砂及源岩抽提物进行对比，目的是探讨其来源。包裹体油生物标志物成熟度参数，C29ααα甾烷20S/(S+R)、C32αβ藿烷22S/(S+R)比值基本达到平衡值，利用甲基菲指数计算的镜质体反射率参数介于0.64%～0.82％之间，显示包裹体中石油烃已接近成熟—成熟热演化阶段；物质来源及沉积环境参数，ααα20R甾烷百分含量C27>C28相似文献   

Mesozoic extension in the Basque–Cantabrian basin (N Spain): Contributions from AMS and brittle mesostructures

In this work we analyse and check the results of anisotropy of magnetic susceptibility (AMS) by means of a comparison with palaeostress orientations obtained from the analysis of brittle mesostructures in the Cabuérniga Cretaceous basin, located in the western end of the Basque–Cantabrian basin, North Spain. The AMS data refer to 23 sites including Triassic red beds, Jurassic and Lower Cretaceous limestones, sandstones and shales. These deposits are weakly deformed, and represent the syn-rift sequence linked to basins formed during the Mesozoic and later inverted during the Pyrenean compression. The observed magnetic fabrics are typical of early stages of deformation, and show oblate, triaxial and prolate magnetic ellipsoids. The magnetic fabric seems to be related to a tectonic overprint of an original, compaction, sedimentary fabric. Most sites display a NE–SW magnetic lineation that is interpreted to represent the stretching direction of the Early Cretaceous extensional stage of the basin, without recording of the Tertiary compressional events, except for sites with compression-related cleavage.Brittle mesostructures include normal faults, calcite and quartz tension gashes and joints, related to the extensional stage. The results obtained from joints and tension gashes show a dominant N–S to NE–SW, and secondary NW–SE, extension direction. Paleostresses obtained from fault analysis (Right Dihedra and stress inversion methods) indicate NW–SE to E–W, and N–S extension direction. The results obtained from brittle mesostructures show a complex pattern resulting from the superposition of several tectonic processes during the Mesozoic, linked to the tectonic activity related to the opening of the Bay of Biscay during the Early Cretaceous. This work shows the potential in using AMS analysis in inverted basins to unravel its previous extensional history when the magnetic fabric is not expected to be modified by subsequent deformational events. Brittle mesostructure analysis seems to be more sensitive to far-field stress conditions and record longer time spans, whereas AMS records deformation on the near distance, during shorter intervals of time.     

Gravitational model of the Taiwan lithosphere (along the profile Taiwan Strait-Taiwan Island-West Philippine basin)

Based on two-dimensional gravity modeling, the density section of the lithosphere beneath Taiwan and the surrounding areas is constructed. According to the density parameters, the lithosphere of this region comprises both the continental and oceanic types. The continental lithosphere is lighter than the oceanic one and demonstrates insignificant density differentiation through the entire section. The oceanic lithosphere is more contrasting with respect of both the crust and mantle density. The complicated Taiwan density structure corresponding to Taiwan Island is defined to be superimposed on the transition zone between the continental and oceanic lithospheric blocks. This structure with contrasting density boundaries is characterized by the elevated and high density values of its constituting heterogeneities. The formation of the Taiwan density structure is related to geodynamic processes in the Taiwan area marking the collision zone between the Eurasian and Philippine Sea plates.