四川盆地油气地质研究

四川盆地是地台内通过深断裂活动而形成的构造—沉积盆地。这些深断裂卷入了上地幔或壳内低速层。深部构造作用控制盖层内的断褶构造发育。川东南高陡背斜带的形成和隐伏的深断裂活动有成因联系。海相致密的碳酸盐岩内气藏的形成和分布,主要受断褶构造发育程度及储层内后生孔洞缝发育程度的控制。低缓的及隐伏的构造圈闭以及后生孔洞缝系统是天然气聚集的场所。川东南及川西区已知的气藏基本上是分布这类的圈闭中。龙门山前隐伏的古逆冲断褶带伴生的构造及裂缝圈闭是重要的油气聚带。近年来的钻探证实了这一预测的正确性。     

Application of quantitative grain fluorescence techniques to study subtle oil migration pathway of lithological reservoir

This paper analyzes the quantitative grain fluorescence (QGF) and quantitative grain fluorescence on extract (QGF-E) properties of 101 rock samples by using quantitative grain fluorescence techniques. The samples are collected from five wells in tight sandstone and thin siltstone in the third sector of the Shahejie Formation in the Niuzhuang sag of the Dongying depression. It was observed that both the tight sandstone and thin siltstone show relatively high fluorescence intensity of hydrocarbon, which suggests that they are possibly good subtle oil-migration pathways in the present or geological time. These thin subtle oil-migration pathways afford important clues for the researches on hydrocarbon accumulation in lithological reservoirs in the middle and lower of Es ₃ in deep sag zone, which has the hydrocarbon source from the upper of Es ₄ when there is no apparent fault playing oil migration conduits to connect lithologic traps and deep source rocks. This study shows good prospect of QGF techniques in discriminating oil migration pathways and paleo-oil zones. The results of this study may be of great significance to the researches on hydrocarbon accumulation mechanism of subtle reservoirs in the Dongying depression and other areas. __________ Translated from Acta Geologica Sinica, 2007, 81(2): 250–254 [译自: 地质学报]     

层序地层学应用于陆相湖盆中隐蔽油气藏的成因解释

研究表明 ,赋存于沉积地层中的油气藏与各种级别的层序地层界面存在着密切的联系。陆相盆地中油气受层序界面、初次湖泛面、最大湖泛面以及更次级的层序地层界面的影响与控制 ,形成不同类型的隐蔽型油气藏。因此 ,从层序地层和沉积过程的角度解剖含油气盆地中不同构造和古地理单元岩性—地层油气藏形成的机理和油气藏类型 ,分析主要层序地层界面对沉积地层中油气藏形成和分布的控制作用 ,具有重要的理论和现实意义。本文从层序地层和沉积过程的角度解剖陆相盆地中不同古地理、古地貌单元隐蔽油气藏形成的机理和油气藏类型 ,阐述主要层序地层界面对油气藏形成过程和分布规律的影响与控制作用 ,并进一步对不同成因类型的油气藏提出简要的分类方案。     

Time-series measurements of Th in water column and sediment trap samples from the northwestern Mediterranean Sea

Disequilibrium between ²³⁴Th and ²³⁸U in water column profiles has been used to estimate the settling flux of Th (and, by proxy, of particulate organic carbon); yet potentially major non-steady-state influences on ²³⁴Th profiles are often not able to be considered in estimations of flux. We have compared temporal series of ²³⁴Th distributions in the upper water column at both coastal and deep-water sites in the northwestern Mediterranean Sea to coeval sediment trap records at the same sites. We have used sediment trap records of ²³⁴Th fluxes to predict temporal changes in water column ²³⁴Th deficits and have compared the predicted deficits to those measured to determine whether the time-evolution of the two coincide. At the coastal site (327 m water depth), trends in the two estimates of water column ²³⁴Th deficits are in fairly close agreement over the 1-month deployment during the spring bloom in 1999. In contrast, the pattern of water column ²³⁴Th deficits is poorly predicted by sediment trap records at the deep-water site (DYFAMED, 2300 m water depth) in both 2003 and 2005. In particular, the transition from a mesotrophic to an oligotrophic system, clearly seen in trap fluxes, is not evident in water column ²³⁴Th profiles, which show high-frequency variability. Allowing trapping efficiencies to vary from 100% does not reconcile the differences between trap and water column deficit observations; we conclude that substantial lateral and vertical advective influences must be invoked to account for the differences.Advective influences are potentially greater on ²³⁴Th fluxes derived from water column deficits relative to those obtained from traps because the calculation of deficits in open-ocean settings is dominated by the magnitude of the “dissolved” ²³⁴Th fraction. For observed current velocities of 5–20 cm s⁻¹, in one radioactive mean-life of ²³⁴Th, the water column at the DYFAMED site can reflect ²³⁴Th scavenging produced tens to hundreds of kilometers away. In contrast, most of the ²³⁴Th flux collected in shallow sediment traps at the DFYFAMED site was in the fraction settling >200 m d⁻¹; in effect the sediment trap can integrate the ²³⁴Th flux over distances 40-fold less than water column ²³⁴Th distributions. In some sense, sediment trap and water column sampling for ²³⁴Th provide complementary pictures of ²³⁴Th export. However, because the two methods can be dominated by different processes and are subject to different biases, their comparison must be treated with caution.     

基于多尺度资料的体系域划分及其意义——以渤海海域沙垒田凸起东南部东二段为例

不同体系域砂体分布和成藏特征存在明显的差别,正确划分体系域对于油气勘探,特别是隐蔽油气藏勘探具有重要意义。相对于海相地层,由于陆相层序本身的复杂性,并不发育明显的坡折带,在进行体系域划分时,不同学者有不同的划分方案,无论在井上还是地震上很难把握各体系域界面的位置。针对这个问题,结合渤海海域沙垒田凸起东南部东二段体系域划分,提出利用多种不同尺度资料层层控制来划分低位域、湖泛域和高位域的思路方法。这种从尺度较大资料到较小尺度资料层层控制来划分体系域的思路方法,可以避免直接从井上来进行划分导致的错误结论,同时相对湖平面变化曲线法的引用,向建立渤海东营组层序划分的标准迈向了坚实一步。     

基于地震沉积学的隐蔽圈闭识别—一个胜利油田的实例分析(英文)

地震沉积学由于受地震分辨率的限制,往往不能定量刻画沉积体的特征,高精度的反演突破了地震传统分辨率的极限,将其引入到地震沉积学的研究领域,能够解决复杂地质条件下的隐蔽圈闭识别问题,从而拓展了地震沉积学的应用范围、改善应用效果。本文采用地震相控非线性随机反演作为核心技术,以地震沉积学理论为主体思路,应用于胜利油田车镇凹陷Es 3段砂砾岩体储层预测,编制了多期砂砾岩体的厚度分布图与沉积微相图,预测了多个隐蔽圈闭目标,经钻探后得到证实,取得了好的应用效果。     

人穷还是地穷?空间贫困陷阱的地统计学检验

引入地统计学的变异函数和交叉相关图方法,以甘肃省六盘山片区为案例区,通过分析村级贫困的空间格局及其与地理因子关系随空间尺度的变化,提供空间贫困陷阱检验关于尺度的深入理解。结果表明：地统计学方法兼具有效性和可靠性,可以反映地理因素—贫困状况关系随时空的变化,对“人地关系”视角下反贫困理论与实践研究具有积极意义。案例区空间贫困陷阱问题突出,村级贫困在一定空间范围内具有自相关性,空间总变异中自相关部分远高于随机性部分,这与不同尺度上地形、气候、区位等结构性因素的影响和控制有关,总体上到县城距离、海拔和总人口3个因子的影响范围和强度较大。     

Role of anisotropy of the initial particle distribution in the acceleration in collapsing solar-flare traps

We consider the behavior of charged particles with an anisotropic initial velocity distribution in a magnetic trap with approaching mirrors in connection with the problem of particle acceleration in solar flares. We show that, irrespective of the charge sign, the efficiency of confinement and acceleration increases with increasing anisotropy factor of the initial distribution α = (T_⊥/T_∥)^1/2. For a positive electric potential of the trap plasma relative to the mirrors, the emerging additional effect of ion expulsion form the trap increases with α_i. The derived estimate of the electric potential suggests an amplification of the initial perturbation and the development of instability.     

The distribution and flux of particulate matter in the Bideford River Estuary,Prince Edward Island,Canada

The temporal and spatial distribution of total and organic particulate matter is investigated in the Bideford River estuary. Particulate matter is homogenously distributed in both the water column and the surface sediment, due to high rates of resuspension and lateral transport. The measured mean sedimentation rate for the estuary is 183·5 g of particulate matter m^?2 day^?1, of which more than half is due to resuspension.The surface sediment of the estuary is quantitatively the dominant reservoir of organic matter, with an average of 902·5 g of particulate organic carbon (POC) m^?2 and 119·5 g of particulate organic nitrogen (PON) m^?2. Per unit surface area, the sediment contains 450 times more POC and 400 times more PON than the water column. Terrestrial erosion contributes high levels of particulate matter, both organic and inorganic, to the estuary from the surrounding watershed. Low rates of sediment export from the estuary result in the accumulation of the terrigenous material. The allochthonous input of terrigenous organic matter masks any relationship between the indigenous plant biomass and the organic matter.In the water column, a direct correlation exists between the organic matter, i.e. POC and PON, concentration and the phytoplankton biomass as measured by the plant pigments. Resuspension is responsible for the residual organic matter in the water column unaccounted for by the phytoplankton biomass.The particulate content of the water column and the surface sediment of the estuary is compared to that of the adjacent bay. Water-borne particulate matter is exported from the estuary to the bay, so that no significant differences in concentration are noted. The estuarine sediment, however, is five to six times richer in organic and silt-clay content than the bay sediment. Since sediment flux out of the estuary is restricted, the allochthonous contribution of terrigenous particulate matter to the bay sediment is minor, and the organic content of the bay sediment is directly correlated to the autochthonous plant biomass.     

Organic carbon and nutrient fluxes to the coastal zone from the Sepik River outflow

The Sepik River is a major contributor of water, sediment and associated organic loads to the coastal waters of northern New Guinea and the Bismarck Sea. We compare dissolved and particulate organic carbon data from September 1997 during an extremely dry El Nino year with those from 1996, 1999 and 2000 during La Nina wet season discharges. Estimated Sepik River flux of DOC is 3.2×10¹⁰ mol yr⁻¹ and POC is 1.1×10¹¹ mol yr⁻¹. The estimates for total river nutrient fluxes to the sea are 1.1×10¹⁰ mol yr⁻¹ for nitrogen and 4.6×10⁸ mol yr⁻¹ for phosphorus. The Sepik DOC flux is about equal to that combined from all four major rivers that enter the Gulf of Papua on the south coast of PNG. The Sepik inorganic PIC flux is low (1.4×10⁸ mol yr⁻¹) as the river does not drain carbonate soils. With a narrow continental shelf, and strong coastal currents, much of this exported material is available for long distance transport into the coastal Bismarck Sea and beyond.