三峡工程运用后坝下游河道泥沙输移变化规律   总被引：2，自引：2，他引：0  

郭小虎  渠庚  刘亚  刘心愿 《湖泊科学》2020,32(2):564-572

三峡工程蓄水后"清水"下泄,坝下游河段将会长期处于严重不饱和状态,水流含沙量沿程恢复将会引起坝下游长距离冲刷,本文根据三峡工程蓄水前、后的实测资料分析了坝下游河道泥沙输移变化规律,探索不同粒径组沙量沿程恢复对河床冲刷的影响,得到以下结论:在蓄水初期d≤0.031 mm沙量恢复主要受河床补给与江湖入汇共同的影响,随着水库下泄该粒径组沙量递减,使得各站该粒径组年均输沙量均远小于蓄水前的水平,沙量恢复仍主要受河床补给与江湖入汇的影响,这是造成坝下游河道发生长距离冲刷的主要原因之一;在蓄水初期0.031 mmd≤0.125 mm沙量恢复主要受河床补给的影响,但江湖入汇的影响较大,随着河床补给量逐渐减少,各站该粒径组年均输沙量均小于蓄水前的水平,沙量恢复仍主要受河床补给的影响,江湖入汇的影响逐渐减小,这也是坝下游河道发生长距离冲刷的主要原因之一; d0.125 mm沙量恢复主要受河床补给的影响,蓄水初期该粒径组沙量在宜昌监利河段沿程恢复速率较快,且在监利站达到蓄水前的水平,随着时间推移,在宜昌监利河段沿程恢复且速率仍较快,在监利站达到最大值,其数值逐渐小于蓄水前的水平,这是造成坝下游河道冲刷重点集中在宜昌监利河段的主要原因.  相似文献   

烃源岩不同性质有机酸的分离及其检测方法     

杜佳宗  何蓓  蔡进功  雷天柱  刘庆  谢忠怀 《高校地质学报》2020,26(5):540-548

烃源岩中的有机酸来源于有机质，但有机质具有不同的赋存形式，有机酸具有不同性质，这将影响有机酸与不同赋存有机质的关系，进而影响分离和检测方法。文章在总结前人对有机质赋存形式和有机酸性质等特征的基础上，提出烃源岩中的有机酸并以非单一的形式存在，具有水溶性、脂溶性和难溶性有机酸三种类型，游离有机质中存在水溶性和脂溶性有机酸，而结合有机质中存在水溶性、脂溶性和难溶性有机酸。因此在检测方法上需采取分步分离的方法，且根据有机酸的性质选取合适的检测方法，即水溶性有机酸利用离子色谱检测，索氏抽提得到的脂溶性有机酸利用气相色谱—质谱检测，通过酸解抽提残渣得到的难溶性有机酸利用红外光谱检测，全面系统地认识烃源岩中有机酸含量和类型等特征。这对进一步探讨烃源岩各种类型有机酸特征和演化规律，深化烃源岩有机质生烃以及有机—无机相互作用等机理都具有重要意义。  相似文献   

准噶尔盆地玛湖凹陷西斜坡三叠系百口泉组扇三角洲优质储集层预测          下载免费PDF全文

桑林翔  刘军  王贵文  王苏天  李全  张云龙 《古地理学报》2020,22(6):1053-1064

针对准噶尔盆地玛湖凹陷西斜坡风南地区三叠系百口泉组扇三角洲砂岩物性空间变化大、优质储集层(孔隙度大于7.4%,渗透率大于0.05×10^-3μm²)预测难的问题,在沉积岩石学、地震沉积学以及地震反演和解释理论指导下,综合利用测井、岩心和三维地震等资料开展了高精度层序地层划分、沉积微相描述和优质储集层地震反演研究。建立了风南井区四级层序地层格架,明确了扇三角洲多期水进水退的充填过程,指出SSQ3和SSQ5是优质储集层的发育层系;识别出扇三角洲平原分流河道、河道间和扇三角洲前缘水下分流水道、河口坝、席状砂等沉积微相,指出扇三角洲平原是优质储集层发育相带;通过应用高分辨层序地层纵向边界和沉积相横向边界约束,进行分层相控叠后地震波阻抗反演,提升储集层预测精度,在SSQ3和SSQ5预测5个优质储集层发育区,提出3口井的井位建议,钻探均获工业油流。  相似文献   

贵州苗匡热矿水地热区水化学特征及热储条件分析     

杨晓飞 《地质与勘探》2020,56(1):94-101

贵州苗匡热矿水地热区大地构造位于江南复合造山黔南坳陷铜仁复式褶皱变形带,区域构造为红石古断裂带与苗匡断裂交汇锐角区,区内出露的地层有前南华系板溪群、南华系、震旦系、寒武系;热矿水水化学类型为HCO_3-Na型,含高氟、锶、锂、偏硅酸;弱碱性水;呈带状中低温热储;区域大地热流供给热量;地下热矿水补给为构造破碎带深远程补给;区域性红石活动断裂带具有导热导水储水性,热矿水被温差、压力差等驱动循环运移至断裂破碎带富集,苗匡次级断裂带在该热储起到连通传导作用;热矿水井口温度45℃,出水量560 m~3/d。研究结果可对该区热矿水勘查开发及利用提供参考和借鉴。  相似文献   

Origin and depositional environments of source rocks and crude oils from Niger Delta Basin: Carbon isotopic evidence     

《China Geology》2020,3(4):602-610

Thirty-nine crude oils and twenty-one rock samples from Niger Delta Basin, Nigeria have been characterized based on their isotope compositions by elemental analysis-isotope ratio mass spectrometry and gas chromatography-isotope ratio mass spectrometry. The bulk carbon isotopic values of the whole rock extracts, saturate and aromatic fractions range from –28.7‰ to –26.8‰, –29.2‰ to –27.2 ‰ and –28.5 ‰ to –26.7 ‰, respectively while the bulk carbon isotopic values of the whole oils, saturate and aromatic fractions range from –25.4 ‰ to –27.8 ‰, –25.9 ‰ to –28.4 ‰ and –23.5 ‰ to –26.9 ‰, respectively. The average carbon isotopic compositions of individual alkanes (nC₁₂-nC₃₃) in the rock samples range from –34.9‰ to –28.2‰ whereas the average isotopic values of individual n-alkanes in the oils range from –31.1‰ to –23.8‰. The δ¹³C isotope ratios of pristane and phytane in the rock samples range from –29.2 ‰ to –28.2 ‰ and –30.2 ‰ to –27.4 ‰ respectively while the pristane and phytane isotopic values range from –32.1‰ to –21.9‰ and –30.5‰ to –26.9‰, respectively. The isotopic values recorded for the samples indicated that the crude oils were formed from the mixed input of terrigenous and marine organic matter and deposited under oxic to sub-oxic condition in lacustrine-fluvial/deltaic environments. The stable carbon isotopic compositions were found to be effective in assessing the origin and depositional environments of crude oils in the Niger Delta Basin.  相似文献   

海拉尔—塔木察格盆地中部富油凹陷高含凝灰质碎屑岩储层成因及油气勘探意义     

蒙启安  李军辉  李跃  邹越 《吉林大学学报(地球科学版)》2020,50(2):569-578

海拉尔—塔木察格盆地中部富油凹陷下白垩统铜钵庙组和南屯组广泛发育高含凝灰质碎屑岩储层，并已于其中获得了工业突破，但对其成因机制认识不清。在岩心、薄片、录井和测井等资料综合研究的基础上，结合大量海拉尔—塔木察格盆地及周边地区的火山事件分析，认为中部富油凹陷发育的高含凝灰质碎屑岩的岩石类型主要包括凝灰质砂岩、凝灰质泥岩、凝灰岩和沉凝灰岩。不同时期、不同凹陷高含凝灰质碎屑岩储层发育特点各异，整体来看从铜钵庙组到南屯组储层中的凝灰质含量越来越低，高含凝灰质碎屑岩储层主要发育在铜钵庙组和南一段沉积时期。高含凝灰质碎屑岩储层中的火山物质并非来源于自身断陷期发生的基性火山活动，而是来自于大兴安岭地区大规模的酸性火山喷发事件。海拉尔—塔木察格盆地高含凝灰质碎屑岩储层的成因机制包括两种类型：一种是同沉积期火山灰直接空降入湖型；另一种是同沉积期火山灰先沉降至陆上经河流搬运后再沉积的水携型。高含凝灰质碎屑岩储层中的火山碎屑物质受有机酸作用易于溶蚀，次生孔隙发育，为深部油气成藏提供了有效储层空间，并且火山喷发活动对优质烃源岩的形成具有促进作用，对于油气勘探具有重要意义。  相似文献   

青藏高原凯蒙蛇绿混杂岩中碱性火山岩的发现及意义     

潘政  史仁灯  黄启帅  陈生生  龚小晗  吴钪  杨可 《岩石矿物学杂志》2020,39(1):18-34

班公湖-怒江洋的关闭时间直接制约青藏高原早期构造演化的认识。最近,在班公湖-怒江缝合带南侧凯蒙蛇绿混杂岩中发现一碱性火山岩,岩性主要是橄榄粗安岩,具粗面结构,斑晶主要是更长石和少量普通辉石,基质主要由更长石、普通辉石和少量填隙的碱性长石组成,有的具辉绿结构。岩石化学成分较一致,Si O2含量介于51.34%~53.91%之间,Ti O2含量为1.02%~1.55%,具有高Al2O3(17.06%~18.46%)和Na2O(4.90%~6.36%)、低K2O(0.05%~0.88%)含量特点,大多数Mg#大于60,最高68.62,里特曼指数(σ)介于3.65~4.47之间,为碱性系列火山岩;富集Sr、Rb、Ba等大离子亲石元素,亏损Nb、Y、Yb等高场强元素,相对富集Zr、Ti,Nb/U、Zr/Nb、La/Yb等比值稳定,分别为7.45~8.51、15.92~17.26和7.26~8.06;(87Sr/86Sr)i值变化范围较小,介于0.706~0.707之间,(143Nd/144Nd)t值在0.512 368~0.512 548之间,说明源区较为一致,结合Ce/Pb-Si O2图解判断结果,认为凯蒙碱性火山岩具有原始地幔、陆壳和深海沉积物源区混合特征。锆石U-Pb同位素定年结果表明该火山岩年龄为101.8±1.1 Ma,可能形成于洋壳俯冲阶段末期,由大陆边缘陆壳与俯冲洋壳板片断离导致软流圈地幔上涌诱发部分熔融所致,推测班公湖-怒江洋大约在早白垩世晚期关闭。  相似文献   

改进的层次分析法与模糊综合评价在评估水库诱发地震震级上限中的应用          下载免费PDF全文

李龙师  金波  冯志仁 《世界地震工程》2020,(3):223-232

为了评估水库诱发地震震级上限，收集了150余例水库诱发地震的震例资料；利用改进的层次分析法优化了各评价指标的权重；应用模糊综合评价方法评估了水库诱发地震震级上限；结合二滩水电站水库诱发地震实例与目前评估水库诱发地震震级最常用的灰色聚类分析法的评价结果进行了对比分析。结果表明:层次分析法与模糊综合评价相结合的震级上限评估方法评价结果更加可靠，可对水库及水工建筑物的建设位置及抗震设防提供参考。  相似文献   

Facies and sequence stratigraphic architecture of the Mural Limestone (Albian), Arizona: Carbonate response to global and local factors and implications for reservoir characterization     

Rachel Aisner-Williams  Charles Kerans 《Sedimentology》2020,67(7):3735-3768

This study documents the detailed facies and sequence stratigraphic architecture of a multi-cyclic patch-reef and its associated ramp interior facies that formed during Oceanic Anoxic Event 1b in the Mural Limestone, Arizona, USA. Ramp interior facies are comprised of bedded wackestone/packstone, rudist build-up and coral–algal patch-reef facies located north of Bisbee, Arizona, at the Grassy Hill locality. The larger multi-cyclic patch-reef that developed coevally ca 5 km to the south of Grassy Hill consists of a high-angle windward margin with a narrow ca 70 m long reef frame containing vertically zonated Microsolena, Actinastrea, diverse branching coral and rudist assemblages, and an 870 m long low-angle leeward margin comprised of reef debris rudstone and grainstone shoal facies. Similar reef geomorphology and orientation is documented across the Gulf of Mexico and reflects the shelf-wide north to north-east-trending prevailing wind and current energies. Controls affecting reef formation and growth patterns include changes in accommodation space associated with low-amplitude global sea-level rise and regional thermotectonic subsidence, local accommodation space and nutrient fluctuations associated with the inner shelf depositional setting within a humid and siliciclastic-rich environment. Four aggradational to retrogradational high-frequency sequences are documented in Arizona: High-frequency sequences 1 and 2 represent the first pulse of patch-reef development in an overall second-order marine transgression over the Sonora/Bisbee Shelf. These sequences correlate to δ¹³C signatures associated with Oceanic Anoxic Event 1b across the Gulf of Mexico and suggest that carbonate reefs persisted on the ramp interior during this time. High-frequency sequences 3 and 4 record a second brief transgression and backstepping of reef facies followed by the final regression of shallow shelf carbonates that correlates to more robust patch-reef development in Sonora, Mexico. The patch-reef at Paul Spur is an excellent outcrop analogue for productive patch-reefs in the Maverick Basin (Comanche Shelf) of Texas. Detailed facies mapping of this outcrop analogue shows that the greatest reservoir potential is contained within the backreef grainstone shoals where primary porosity of up to 15% is observed.  相似文献   

Robust numerical implementation of a 3D rate-dependent model for reservoir geomechanical simulations     

Giovanni Isotton  Pietro Teatini  Massimiliano Ferronato  Carlo Janna  Nicolò Spiezia  Stefano Mantica  Giorgio Volonte 《国际地质力学数值与分析法杂志》2019,43(18):2752-2771

A 3D elasto-plastic rate-dependent model for rock mechanics is formulated and implemented into a Finite Element (FE) numerical code. The model is based on the approach proposed by Vermeer and Neher (A soft soil model that accounts for creep. In: Proceedings of the International Symposium “Beyond 2000 in Computational Geotechnics,” pages 249-261, 1999). An original strain-driven algorithm with an Inexact Newton iterative scheme is used to compute the state variables for a given strain increment.The model is validated against laboratory measurements, checked on a simplified test case, and used to simulate land subsidence due to groundwater and hydrocarbon production. The numerical results prove computationally effective and robust, thus allowing for the use of the model on real complex geological settings.  相似文献