Marine hydrocarbon source rocks of the Upper Permian Longtan Formation and their contribution to gas accumulation in the northeastern Sichuan Basin,southwest China

Identification of the main hydrocarbon source rocks of the large Puguang gas field (northeastern Sichuan Basin, southwest China) has been the subject of much discussion in recent years. A key aspect has been the lack of a comprehensive understanding of the development of hydrocarbon source rocks of the Upper Permian Longtan Formation, which had been thought to contain mainly coal seams and thick carbonate layers. In this paper, based on geological data from more than ten wells and outcrops and their related mineralogy and geochemistry, we investigated the depositional environment and main factors controlling organic matter enrichment in the Longtan Formation. We propose a model which combines information on the geological environment and biological changes over time. In the model, organic matter from prolific phytoplankton blooms was deposited in quiescent platform interior sags with rising sea-levels. During the Longtan period, the area from Bazhong to Dazhou was a platform interior sag with relatively deep water and a closed environment, which was controlled by multiple factors including syngenetic fault settling, isolation of submarine uplifts and rising sea-levels leading to water column stratification. Although the bottom water was anoxic, the phytoplankton were able to bloom in the well-lit upper euphotic zone thus giving rise to a set of sapropelic black shales and marlstones containing mostly algal organic matter with minor terrestrial contributions. As a consequence, these rocks have a high hydrocarbon generation potentials and can be classified as high-quality source rocks. The area from Bazhong to Dazhou is a center of hydrocarbon generation, being the main source of reservoired paleo-oils and presently discovered as pyrobitumen in the Puguang gas field. The identification of these source rocks is very important to guide future petroleum exploration in the northeastern Sichuan Basin.     

Quantitative characterization of connectivity and conductivity of sandstone carriers during secondary petroleum migration,applied to the Third Member of Eocene Shahejie Formation,Dongying Depression,Eastern China

Studies on migration pathways remain qualitative, albeit extensive quantification of migration forcing. In this study, hydrocarbon carriers are defined as carrier units and their corresponding carrier beds for the Third Member of Eocene Shahejie Formation in the Dongying Depression, Bohai Bay Basin, eastern China, on the basis of their lithofacies and physical properties, spatial relationships, and data availability; secondary migration conduits are then quantified. A carrier unit is defined as a stratigraphic unit that contains microscopically porous and permeable carrier beds and is covered by regional seals. The carrier beds are macroscopically and physically connected to each other within a carrier unit and are hydrodynamically connected during secondary migration. A method of quantifying sandstone carrier units using common physical properties is developed. First, a carrier unit containing potential carrier beds is identified on the basis of lithofacies and their lateral changes. Second, physical connectivity of sandstone carrier beds is assessed on the basis of percolation theory. Third, the hydrodynamic connectivity of a sandstone carrier unit is analyzed using effective parameters that may reflect the hydraulic circulation in the carrier unit. Last, the conductivity of a sandstone carrier bed is quantitatively characterized using appropriate physical property parameters. The results for sandstone carrier units in the Third Member of the Shahejie Formation are used in numerical models addressing Pleistocene secondary migration. The model results explain the discovered accumulation and hydrocarbon shows well; and the model predictions on exploration targets have been confirmed by drilling.     

因子分析在海河流域石油类污染综合评价中的应用(英文)

基于因子分析对2012~2013年海河流域pH、DO、COD、BOD5、氨态氮和总石油烃等6项水质指标的监测数据进行统计,并对其中四项指标进行水污染综合指数评估,旨在对海河水质进行较为系统的评价。结果显示,BJ1和HB2两个站位水质属于Ⅳ类标准,其余各站位均为Ⅴ类;各站位综合评价结果得到海河流域指数为1.44,说明海河流域处于污染状态,其污染程度超过该流域功能区的标准。因子分析发现,COD、DO和NH3-N之间差异显著(P0.05);主成分分析显示,除pH和BOD5外,其余指标都在0.70以上;COD、DO、NH3-N和TPH的贡献率较高,其中总石油烃的贡献率为100%,因此可以认为该海域的污染类型属于有机污染,且石油烃污染较为突出。     

List of members of the Editorial Board

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鄂尔多斯盆地延长探区低渗致密油气成藏理论进展及勘探实践

延长石油集团在鄂尔多斯盆地大力推动石油、天然气、页岩气勘探开发理论研究和技术攻关,多类型资源协同发展,取得显著效果。在石油勘探方面,提出延长组特低渗石油“交替式”成藏理论认识,建立盆地中生界多期差异性成藏新模式,近10年特低渗石油年均探明地质储量超1×10⁸ t。建立细粒沉积风暴、地震等控砂理论,以及甜点预测方法,致密油累计探明地质储量2.1×10⁸ t。针对致密气田砂体成因机理不明、天然气运聚成藏规律不清等主要难题,揭示了“浅水环境岸线频繁迁移控砂”机制,建立了致密砂岩气优质储层成储模式,明确纯石英砂岩和富石英低塑性颗粒岩屑砂岩是致密气分布的“甜点”,形成了基于多要素、全过程天然气运聚模拟的目标优选技术。经勘探实践,发现了延安气田,累计探明天然气地质储量7 635×10⁸ m³。页岩气方面,提出陆相页岩气“三元”成藏富集地质理论的创新认识,认为湖相优质页岩是陆相页岩气富集高产的物质基础,多类型、跨尺度的复杂孔隙网络决定页岩气赋存条件,厚层页岩自封闭能力及高压是保存的关键,实现陆相页岩气产量突破。未...     

Rapid delineation of subsurface petroleum contamination using the site characterization and analysis penetrometer system

 The Site Characterization and Analysis Penetrometer System (SCAPS) was used to investigate subsurface petroleum contamination at Aberdeen Proving Ground, Maryland. The SCAPS is a rapid site-screening tool developed by the Tri-Services (U.S. Army, Navy, and Air Force) to reduce the cost of installation restoration activities. The system, consisting of a geophysical cone penetrometer fitted with a laser-induced fluorescence petroleum sensor, is capable of simultaneous, real-time delineation of subsurface stratigraphy and petroleum contamination. Onsite processing of the SCAPS data allows three-dimensional visualization of both subsurface stratigraphy and petroleum contaminant distribution. The site investigation described herein successfully identified three distinct areas of subsurface petroleum contamination caused by leaking underground storage tanks containing No. 2 healing oil. The SCAPS petroleum sensor response was verified by obtaining 20 soil samples and performing onsite and conventional laboratory analyses for petroleum contaminants. Verification sample results indicate a strong correlation between the SCAPS fluorescence data and conventional measures of petroleum contamination. This investigation illustrates the capabilities of the SCAPS for rapid site characterization. Received: 27 November 1995 · Accepted: 11 December 1995     

PETROLEUM GEOLOGY

正20140890 Bai Ru(National Key Laboratory of Continental Dynamics,Department of Geology,Northwest University,Xi’an 710069,China);Zhang Jingong Characteristics of Pore Character and Its Controls of Chang 6Reservoir of Zhiluo Oilfield(Journal of Northwest University,ISSN1000-274X,CN61-1072/N,     

SEDIMENTARY PETROLOGY

正20141430 Chen Ji(Key Laboratory of Petroleum Resources,Chinese Academy of Sciences,Lanzhou 730000,China);Shi Ji’an Sedimentary Facies and Models for the Palaeogene-Neogene Deposits on the Northern Margin of the Qaidam Basin,Qinghai Province(Sedimentary Geology and Tethyan Geology,ISSN1009-3850,CN51-1593/P,33(3),2013,p.16-26,14 illus.,16 refs.)     

黄铁矿对有机质成烃的催化作用讨论

粘土矿物，碳酸盐，石英等无机矿物对有机质演化的催化作用已被确认，有机质干酪根类型还与黄铁矿含量，形态有关，而其中硫的含量直接影响到干酪根反应的活化能，反应速率，指出黄铁矿也是一种有效的催化剂。鉴于世界原油中有很大一部分产自高硫酪根，深入研究其中的机理是当前石油地球化学中的一项刻不容缓的任务。