泵吸反循环灌注桩钻进泵量选择的探讨

砂石泵泵量的选择是泵吸反循环钻孔灌注桩钻进工艺的关键,通过公式演算,提出泵吸反循环钻孔灌注桩钻井泵量的选择方法。     

云南新生代断陷盆地的环境地质记录

盆地的环境地质记录是从盆地的形成、发展演变、沉积物形成的地球化学与古气候环境、沉积物堆积后所经历的压实、成岩来加以研究的。除无机介质(矿物)外的有机质,在成岩压实受热过程中化学成分与结构的变化,也是盆地环境地质记录的一部分,环境地质研究的归宿是对矿产—化石燃料形成与潜能的估价,完整的研究应该包括化石燃料形成(成烃成煤)环境及成藏(保存)环境等。对云南滇西陇川、瑞丽及保山等三个新生代断陷盆地环境地质记录的研究揭示,在极其相似的盆地形成演变、沉积地球化学与古气候、成岩与成烃背景基础上,化石燃料的形成与潜能在三个盆地具有差异性;指出陇川盆地以找寻煤型气及初熟(低熟)油为主,保山盆地以寻找浅部生物成因气及煤型气为主,瑞丽盆地相对潜能较差,仅有生物气浅部产出的可能。     

中国海相碳酸盐岩油气田的现状和若干特征

截止1998年底,中国天然气探明储量有40．7％存在于碳酸盐岩地层,共有7个碳酸盐岩大气田;而与碳酸盐岩储层以及海相烃源岩有关的原油探明储量不到7％。中国碳酸盐岩生烃问题长期以来是碳酸盐岩油气勘探中的一个关键问题,目前初步认为中国碳酸盐岩中的工业性油气田多数不是自生自储的,而需要外部存在有机质丰度较高的烃源岩。烃源岩的有机质质量和数量均受沉积环境的影响,多数情况下陆表海碳酸盐岩中烃源岩不发育。除了南海的第三系,中国海相碳酸盐岩储层普遍时代古老、物性差、非均质性强,储层的发育取决于后期改造作用。岩溶作用对碳酸盐岩储层的形成意义十分重要,不整合面之下是碳酸盐岩油气藏形成的有利层段。     

Multiaxial Fatigue Analysis on Reeled Deepwater Steel Catenary Risers with Girth Weld Defects

In the present study, we simulated the reel-lay installation process of deepwater steel catenary risers (SCRs) using the finite element method and proposed multiaxial fatigue analysis for reeled SCRs. The reel-lay method is one of the most efficient and economical pipeline installation methods. However, material properties of reeled risers may change, especially in the weld zone, which can affect the fatigue performance. Applying finite element analysis (FEA), we simulated an installation load history through the reel, aligner, and straightener and analyzed the property variations. The impact of weld defects during the installation process, lack of penetration and lack of fusion, was also discussed. Based on the FEA results, we used the Brown-Miller criterion combined with the critical plane approach to predict the fatigue life of reeled and non-reeled models. The results indicated that a weld defect has a significant influence on the material properties of a riser, and the reel-lay method can significantly reduce the fatigue life of SCRs. The analysis conclusion can help designers understand the mechanical performance of welds during reel-lay installation.     

Enhanced multi-layer fatigue-analysis approach for unbonded flexible risers

This paper proposes an enhanced approach for evaluating the fatigue life of each metallic layer of unbonded flexible risers. Owing to the complex structure of unbonded flexible risers and the nonlinearity of the system, particularly in the critical touchdown zone, the traditional method is insufficient for accurately evaluating the fatigue life of these risers. The main challenge lies in the transposition from global to local analyses, which is a key stage for the fatigue analysis of flexible pipes owing to their complex structure. The new enhanced approach derives a multi-layer stress-decomposition method to meet this challenge. In this study, a numerical model validated experimentally is used to demonstrate the accuracy of the stress-decomposition method. And a numerical case is studied to validate the proposed approach. The results demonstrate that the multi-layer stress-decomposition method is accurate, and the fatigue lives of the metallic layers predicted by the enhanced multi-layer analysis approach are rational. The proposed fatigue-analysis approach provides a practical and reasonable method for predicting fatigue life in the design of unbonded flexible risers.     

北极海水中可培养寡营养细菌多样性

北极科考带回北冰洋海水,经透析室连续富集培养,培养基再培养获得膜上生长的可培养寡营养细菌.应用16SrDNA文库技术对北极N83站和C19站海水中可培养寡营养细菌多样性进行了研究.结果表明,样品中细菌多样性丰富.N83站水样可培养寡营养细菌分为3部分:优势菌群为α-变形菌纲(Alphaproteobacteria),在...     

红花沟金矿用MK-3型激电仪取得的效果

红花沟金矿位于内蒙台背斜内三级构造云雾山隆起的东北端.隆起北以深断裂与地槽相接;南以大断裂与坳陷分界.窿起、坳陷及深大断裂均呈北东向延展.区内各矿点均产于太古界变质岩中. 三年来,在该区用MK-3型时域激电仪进行了电阻率和激电测量,得到许多异常和异常带.由于矿脉小、浮土厚,工作结果只能圈定与矿脉赋存有关的强烈花岗岩化地带和斜长角闪岩地带.在这些地段,电阻率异常宽,阻值不大;激电异常变化也是宽而低缓.据此难以准确圈定矿脉的空间位置. MK-3是由加拿大进口的一种时域激电     

南海北部陆架区海域深水金线鱼的产卵场

根据 1997年 12月至 1999年 6月在南海北部陆架区海域进行的底拖网渔业资源调查的资料 ,统计分析了南海北部陆架区海域深水金线鱼性腺成熟期的组成及分布、季节性变化和水深变化规律。结果表明 ,南海北部陆架区海域深水金线鱼的产卵场位于广东沿海水深 6 0～ 15 0m海区 ,尤其是珠江口外海区的群体更为密集 ;该生殖群体的产卵期较长 ,且分布范围大 ,未见有显著性变化。     

2021年青海玛多MW7.4地震GNSS同震形变场及其断层滑动分布

2021年5月22日青海玛多M_W7.4地震作为发生在巴颜喀拉块体内部的一次强震,再次引起了人们对该地区地震活动性的强烈关注.本文基于震后GNSS流动观测和区域连续GNSS站资料,解算了106个站点的同震形变及其中17个站点的高频形变波形.同震形变场显示玛多地震具有典型的左旋走滑特征,GNSS观测到的最大同震位移达到1.2 m.GNSS与InSAR数据相符度较高,GNSS提供了准确的近场形变信息.基于GNSS同震形变场,本文反演了断层滑动分布,并计算了发震断层上产生的库仑应力变化.结果表明,发震断层的滑动破裂存在多个凹凸体,破裂分段特征明显且出露地表,与野外地表破裂考察和余震分布吻合,主体破裂位于断层面0~10 km的浅部区域,最大滑动量达到4.6 m,地震矩1.63×10²⁰N·m,矩震级为M_W7.4;发震断层上静态库仑应力增加区域与余震分布具有一致性,说明余震主要是由静态库仑应力加载而触发的.