南方电网失步解列系统特性RTDS仿真试验研究

对南方电网目前配置的失步解列系统的定值设置及协调配合进行实时仿真研究,建立了南方电网交直流混合实时数字仿真(RTDS)模型,搭建了由RTDS、失步解列系统、功率放大器、直流控制保护装置组成的实时闭环试验系统.试验中模拟了线路故障、直流闭锁及其组合故障,全面测试了严重故障下南方电网失步解列系统动作特性,分析比较了失步解列系统分别在开环控制、闭环控制两种RTDS实时仿真测试模式下的动作规律,并与BPA离线仿真人工判断结果相比较.结果表明针对检验的几种典型严重故障方式,南方电网失步解列系统动作配合正确.试验克服了厂家试验存在的功能单一、离线仿真人工估计等缺陷,是RTDS应用于失步解列系统研究的重大尝试,为进一步将RTDS应用于整个安稳系统实时仿真研究积累了方法经验.     

南方电网2008年安全稳定控制策略

考虑到2008年南方电网的网架结构、送电水平和电源布局都有变化,有必要分析2007年安稳控制策略的适应性,并根据分析结果进行适当调整。文章通过对南方电网2008年网架结构以及典型运行方式下的严重故障进行扫描分析,找出其运行中存在的薄弱环节,按照简化、优化原则,提出了合理、可行的控制策略。这些控制策略已在现场的安稳装置中实现,并且运行状况良好。     

DIAGENETIC CONTROLS ON THE RESERVOIR QUALITY OF TIGHT OIL-BEARING SANDSTONES IN THE UPPER TRIASSIC YANCHANG FORMATION,ORDOS BASIN,NORTH-CENTRAL CHINA

Tight oil-bearing sandstones in the Chang 4+5, 6 and 7 Members of the Upper Triassic Yanchang Formation in the Ordos Basin, north-central China, in general consist of fine-grained, moderately- to poorly-sorted lithic arkoses (average Q₅₃F₃₀R₁₇) deposited in a fluvial-dominated lacustrine-deltaic environment. Diagenetic modifications to the sandstones include compaction and cementation by calcite, dolomite, ankerite, quartz, chlorite, kaolinite and illite, as well as partial dissolution of feldspars and minor rock fragments. Porosity ranges up to ~7% of the rock volume and was reduced more by cementation than by compaction. Fractures (tectonic macrofractures and diagenetic microfractures) provide important oil migration pathways and enhance the sandstones' storage potential. The pore network is heterogeneous due to processes related to deposition and diagenesis, and there are considerable spatial variations in porosity and pore connectivity. The pore system includes both macropores and micropores, and pore network variations depend on the type and distribution of authigenic cements. An analysis of the diagenetic and porosity characteristics of core samples of the Yanchang Formation sandstones from wells in the Youfangzhuang oilfield resulted in the recognition of six petrofacies (A-F) whose characteristics allow reservoir quality to be predicted. Fluid performance analysis for selected sandstone samples using nuclear magnetic resonance combined with helium porosity and air permeability shows that high permeability and large pore throats together result in high movable fluid saturation potential, and that effective pore spaces and throats are beneficial for hydrocarbon storage and flow. Relatively higher porosity and permeability tend to occur in petrofacies B sandstones containing abundant pore-lining chlorite with lesser kaolinite and minor carbonate cements, and in petrofacies C sandstones with abundant pore-filling kaolinite cement but little chlorite and carbonate cements. These petrofacies represent the best reservoir-quality intervals. A reservoir quality prediction model is proposed combined with the petrofacies classification framework. This model will assist future development of tight sandstone reservoirs both in the Upper Triassic Yanchang Formation in the Ordos Basin and elsewhere.     

HIGHER LANDPLANT –DERIVED BIOMARKERS IN LIGHT OILS AND CONDENSATES FROM THE COAL-BEARING EOCENE PINGHU FORMATION,XIHU SAG,EAST CHINA SEA SHELF BASIN

The Cenozoic Xihu Sag in the East China Sea Shelf Basin contains large reserves of coals together with liquid petroleum derived from coal-associated sediments. However, the origin of the petroleum is not well understood. In this study, biomarker assemblages in a suite of recently discovered light oils and condensates from the Paleogene succession in the western margin of in the Xihu Sag were investigated using gas chromatography – mass spectrometry. The objectives were to investigate the samples' thermal maturity and the depositional environment of the precursor source rocks which generated the oils. The light oils are believed to have been derived from coaly source rocks in the Eocene Pinghu Formation. Assessment of thermal maturity based on CPI, pristane/n-C₁₇ ratio and isomerisation ratios of C₂₉ steranes and C₃₁ homohopanes suggest that the hydrocarbons have a relatively low maturity in the early to mid oil generation window. The distribution of isoprenoids relative to n-alkanes, the high pristane/phytane ratios (5.1–10.7), the almost complete absence of gammacerane and C₃₃₊ homohopanes, and the low dibenzothiophene/phenanthrene ratios indicate that the source rocks of the hydrocarbons were deposited in a relatively oxic and sulphate-poor fluvio-deltaic environment which was favourable for coal measure development. Abnormally abundant gymnosperm-derived diterpanes including labdane, 19-norisopimarane, fichtelite, rimuane, pimarane, isopimarane, 17-nortetracyclic diterpene, phyllocladanes and abietane were detected in the samples analysed. 16a(H)-Phyllocladane was identified unambiguously and kauranes were confirmed to be absent. In addition, three 19-norisopimarane isomers, 13β(H)-atisane, and 20-normethylatisane were tentatively identified in the studied samples. The distributions of n-alkanes, isoprenoids and regular steranes, the presence of 4β(H)-eudesmane and oleanane, high Pr/Ph ratios and the abundant diterpanes together suggest that the hydrocarbons were derived from a coaly source rock. Gymnosperms of the conifer families Cupressaceae (especially the former Taxodiaceae) and Pinaceae are interpreted to be the major source of the diterpanes and to have made a significant contribution to the coaly source rock. However, the low abundance of oleanane relative to diterpanes may underestimate the contribution from angiosperms relative to gymnosperms. This could be due to differential preservation and alteration of the di- and triterpenoid precursors during diagenesis and the occurrence of non-specific precursors in higher land plants.     

东海西湖凹陷平湖组Ⅲ型干酪根暗色泥岩生排烃模拟

为更真实地刻画烃源岩生排烃过程及为油气资源定量评价提供合理的关键参数,对东海陆架盆地西湖凹陷始新统平湖组Ⅲ型干酪根暗色泥岩开展了半开放体系下热压生排烃模拟实验研究。模拟结果显示,该暗色泥岩的生排烃过程主要包括初期缓慢生油阶段（R_o=0.5%~0.7%）、早期快速生排油阶段（R_o=0.7%~1.0%）、中期油裂解气阶段（R_o=1.0%~1.5%）、后期主生气阶段（R_o=1.5%~2.3%）及晚期生干气阶段（R_o>2.3%）。该烃源岩的排油门限（R_o）约为0.7%,其生气范围较宽（R_o=1.0%~3.0%）,且在高—过热演化阶段仍具备较强的生气能力,是以生气为主的气源岩。通过对实验结果和样品生排烃特征的研究,建立了一套西湖凹陷平湖组Ⅲ型暗色泥岩生气与生排油过程及潜力评价的数学模型,可用于该区资源量计算。与封闭体系的高温高压黄金管热模拟实验相比,半开放体系下烃源岩热压生排烃模拟实验的累计产油率更高,也更接近实际地质情况,据此评价可使西湖凹陷具有更大的油气资源量。     

国六排放标准对润滑油行业的影响

研究国六标准实施后对润滑油行业的影响。主要通过概括国六标准排放限值的变化等内容和符合国六要求的汽油机和柴油机技术路线,分析国六发动机的新技术或设备对发动机润滑油的技术要求,讨论满足国六发动机的润滑油规格。国六标准实施将大力助推润滑油行业产品结构升级。     

蜡油加氢装置生产国V柴油的工业实践

为应对柴油液相循环加氢装置停工换剂期间柴油无法出厂的问题,中国石化石家庄炼化分公司进行了采用蜡油加氢装置生产国Ⅴ柴油的工业实践。结果表明,在装置处理量为175 t/h、反应器入口温度为352 ℃、反应压力为9.4 MPa、氢油体积比为500、体积空速为0.97 h-1、分馏塔塔底温度为222 ℃、分馏塔塔顶压力为0.11 MPa的工艺条件下,柴油产品硫质量分数稳定在3 μg/g,达到国Ⅴ柴油标准。在蜡油加氢装置生产国Ⅴ柴油期间发现冷高压分离器超负荷、加热炉超负荷、尾油出装置温度高、柴油水含量高等问题,问题皆得以解决。工业实践的结果可为蜡油加氢装置生产国Ⅴ柴油提供数据支撑及改造依据。     

论三角洲对南海海相油气田分布的控制作用

南海是全球重要的油气富集区之一,在新生界已发现约340个油气田,原油可采储量达17.6×10⁸t,天然气可采储量为5.0×10¹²m³,油气主要富集于渐新世以来三角洲—海相沉积体系中,三角洲对南海含油气盆地成烃、成储和成藏具有重要的控制作用。海陆过渡相烃源岩是南海含油气盆地的重要烃源岩,三角洲体系是煤系烃源岩发育的重要场所,河流—三角洲体系所携带的陆生高等植物有机质有利于陆源海相泥质烃源岩的发育。三角洲体系发育的碎屑岩储层厚度大、分布广、物性好,与海相泥岩构成良好的储盖组合。三角洲是南海油气富集的重要场所,三角洲对南海海相油气田的形成和分布具有重要的控制作用。     

对于组建国家油气管网公司的思考及建议

2019年3月19日有关部门审议通过了《石油天然气管网运营机制改革实施意见》,组建国家油气管网公司是其中的核心内容。这标志着我国油气体制改革的实施进入了重点推进阶段。为了加深对于油气市场化改革的理解,从优化油气行业市场结构、促进油气管网基础设施互联互通和公平开放、推进油气价格市场化改革、推动国有油气企业转型升级发展等4个方面阐述了组建国家油气管网公司的积极意义,并就国家油气管网公司成立与油气体制改革、国有油气企业、管网投资建设、地方管网协同、油气价格、民生用气保障等相关问题进行了探讨。进而基于我国能源行业发展的特点、油气产业的现状和长期改革实践的经验和教训,提出了相关建议:(1)加快推进油气产业链上下游环节改革;(2)尽快推进提升监管能力的制度建设;(3)支持管网投资建设运营主体多元化;(4)做好国家管网和地方管网的统筹协调;(5)重点推进天然气基础设施整合及开放;(6)处理好管网公司组建涉及的资产、长期贸易协议、配套运行和监管规则等其他问题。以期更好地达成组建国家油气管网公司和推进油气体制改革的目标。