2D stabilised analytic signal method in DC pole-pole potential data interpretation

Using analytic signal method, interpretation of pole-pole secondary electric potentials due to 2D conductive/resistive prisms is presented. The estimated parameters are the location, lateral extent or width and depth to top surface of the prism. Forward modelling is attempted by 2D-Finite Difference method. The proposed stabilised analytic signal algorithm (RES2AS) uses Tikhonov’s regularization scheme and FFT routines. The algorithm is tested on three theoretical examples and field data from the campus of Roorkee University. The stability of RES2AS is also tested on synthetic error prone secondary pole-pole potential data.     

塔河油田3区石炭系超深薄层碎屑岩储层预测研究

针对塔河油田3区石炭系卡拉沙依组地震数据很难识别薄砂体的问题,对比分析了采用地震资料提频处理、分频处理、储层高分辨率敏感参数反演等不同手段得到的储层预测结果,筛选出高分辨率储层敏感参数反演作为卡拉沙依组砂泥岩段储层主要预测手段。通过探讨砂泥岩对声波时差的响应,以及对比分析自然电位、自然伽马以及补偿中子孔隙度与声波时差的关系,确定自然电位与声波时差的相关性最好,由此选取自然电位作为最佳电性敏感参数参与高分辨率敏感参数反演预测。从井点、剖面、平面等方面检验和评价高分辨率储层预测成果,结果表明其反演预测效果较好,符合塔河油田3区石炭系的储层预测要求,实现了对石炭系主力砂体空间展布的解释与描述,建立了塔河油田3区石炭系卡拉沙依组储层模型。     

新安江水库(千岛湖)水质时空变化特征及保护策略

为探索新安江水库(千岛湖)水质的变化规律及其影响因素,利用2009-2010年的逐月水质监测数据,结合文献资料,对新安江水库水质时空变化进行了综合分析.结果表明:在时间分布上,透明度、总氮、总磷及叶绿素受水文季节变化过程、浮游生物生长及人类活动等的综合影响,具有明显的季节变化特征,特别是上游街口断面各指标季节差异显著.空间分布上,上游水质明显劣于下游水质,上游水域透明度低,氮、磷及叶绿素含量高,反映出外源供给和人类活动对新安江水库水质的决定性贡献,控制外源污染是新安江水库水质提升的关键.统计分析表明,新安江水库主要感官指标透明度主要受控于藻类生物量,而藻类生物量变化与氮、磷营养盐的含量关系密切.严格控制入库营养盐通量,控制浮游植物生物量的季节性异常增殖已成为解决新安江水库水环境问题的核心.另外,新安江水库经济鱼类赋存量与捕捞量对水质有一定影响,年度捕捞量与水体透明度具有反相关关系,不能排除鱼类密度过高导致的生态系统失调的可能.因此,要进一步开展渔业养殖的水质效应研究,加强渔业管理,确定科学合理养殖模式,保证新安江水库水质的改善.     

基隆凹陷构造演化特征及油气资源潜力

基隆凹陷是东海陆架盆地主要沉积凹陷,自晚白垩世以来,共经历了裂陷期、裂后沉降期和区域沉降期等3个构造演化阶段,沉积了巨厚的新生代地层。基隆凹陷为一被断层复杂化的半地堑凹陷,属于东断西超的箕状断陷。新生代自西向东可划分为西部缓坡断阶带、中央洼陷带和东部陡坡带3个构造带。始新统至中新统发育多套生储盖组合,表明基隆凹陷具有良好的油气资源潜力。     

镇江长江豚类省级自然保护区鱼类多样性及年际变化

【目的】调查了解镇江豚类保护区鱼类资源状况,丰富鱼类资源本底数据。【方法】于2013、2016和2019年,分别开展3次渔业资源调查,对该区域鱼类种类组成、优势种、体型大小及群落多样性进行统计分析。【结果】共记录鱼类68种属于7目13科47属;鲤形目(Cypriniformes)鱼类种类占比较为稳定,鲇形目(Siluriformes)鱼类资源量有下降趋势,鲈形目(Siluriformes)鱼类种类占比上升明显;不同年份优势种替代较为明显;2016年的物种丰富度指数和多样性指数最高,分别为6.528、3.026。【结论】保护区鱼类资源较为丰富,但不同年份鱼类群落变化较为明显,渔业资源面临小型化趋势。     

Age,growth and natural mortality of blue jack mackerel Trachurus picturatus (Carangidae) from the Canary Islands,Spain (NW Africa)

Status assessment of exploited fish populations is a general requirement to ensure sustainability of fisheries in both global and local contexts. The blue jack mackerel Trachurus picturatus (Bowdich, 1825) remains unassessed in a data-limited fishery in the eastern central Atlantic, within the waters of the Canary Islands (Spain) off the coast of northwest Africa. This is the most southwestern targeted fishery in the species’ distributional range. To obtain basic life-history information, a total of 2 472 specimens were analysed, ranging from 10.2 to 31.9 cm total length, from samples collected monthly between March 2005 and March 2006. Length–weight relationships (a = 0.0023; b = 3.418; R ² = 0.97) showed no significant difference between sexes. Deposition periodicity and coherence of the ageing criteria were verified by analysis of the monthly evolution of the otolith edge. Ages were estimated by counting annual growth rings on whole otoliths, with these fish ranging from age 0 to 6 years. The von Bertalanffy growth model, which was used to estimate growth parameters from both direct readings and back-calculated length-at-age data, gave good statistical fits. The parameters from the direct readings were: L∞ = 34.9 cm; k = 0.214 y^–1; t ₀ = ?2.545 y (R ² = 0.84), and the natural mortality rates estimated from empirical methods varied between 0.20 and 0.55 y^–1.