Possible impact of dam reservoirs and river diversions on material fluxes to the Gulf of Thailand   总被引：1，自引：0，他引：1  

Manuwadi Hungspreugs  Wilaiwan Utoomprurkporn  Penjai Sompongchaiyakul  Watanee Heungraksa 《Marine Chemistry》2002,79(3-4)

Thai people have always been agricultural-based, although rainwater is not enough to sustain year-round agricultural practice. The first earth-filled dam was built across a valley near Sukhothai over 700 years ago. Now, there are six major multipurposed dam reservoirs, among which the largest is the Sri Nakarind (SN) built across the Kwae Yai River, the main branch of the Mae Klong River in the western part of Thailand. The first multipurposed dam reservoir built on the Chao Phraya (largest) River System is the Bhumibhol Dam on the Ping River. In this paper, the two Mae Klong River Dam Reservoirs and their biology and chemistry are discussed. Also investigated are the historical records of material fluxes to the Gulf of Thailand in down-core sediment profiles and in 40-year bands of coral, Porites lutea, taken from the Upper Gulf of Thailand near Si Chang Island. Sediment cores studied did not show clear decreases in the biogenic silica concentration in the Upper Gulf area after the building of dams. Part of the reasons might be the higher rate of dissolution of silica in tropical waters bioturbation of surface layers or the constant disturbance of the bottom sediment by fishermen using bottom trawls. The record in the coral bands seems to be more promising in reflecting the material flux change due to dam construction. An attempt to detect changes in diatom population with time due to the expected decrease in siliceous material discharge was not possible because there was a change from the use of 70 μm mesh size to 20 μm mesh size resulting in the increase of species and biomass, although the diatom percentage remained above 80% in all estuarine samples.  相似文献   

显微荧光光谱技术在油气成藏研究中的应用——以塔里木盆地巴什托上古生界油气藏为例     

孙守亮  郭巍  李永飞  苏飞 《世界地质》2016,35(1):173-183

根据原油在紫外光的激发下产生荧光的特点,通过显微荧光光谱方法,对有机包裹体的荧光光谱进行定量化分析,利用其主峰波长与荧光强度、主峰波长与红/绿商的相关性,对塔里木盆地巴什托上古生界油气藏的成藏特征进行了初步研究。在研究区所采集的32块岩石样品中共获得64个荧光光谱数据。分析结果表明,巴什托上古生界油气藏存在3个油源,其主峰波长主要集中在439~443nm、469~472 nm和498~503 nm三个值段上,且为不同演化阶段的混源充注。前两者来自于寒武—奥陶系烃源岩,由下至上充注成藏;后一油源来自于石炭系巴楚组,随演化程度的变化同时向上、下两个方向充注。综合同期捕获不同主峰波长的有机包裹体,推测研究区至少存在4期油充注、1期天然气充注。  相似文献   

伊通盆地鹿乡断陷C区块含油饱和度与含油性分析     

赵石乐  程日辉  蒋飞  许中杰  刘柏依 《世界地质》2016,35(4):1084-1094

综合研究伊通盆地鹿乡断陷双二段储层的岩性、含油性和含油饱和度,确定了适用于本区的含油饱和度计算方法,并与实际含油性进行了对比,分析了沉积和构造对含油性的影响。研究区双二段含油储层的岩性以粉砂岩、细砂岩和砂砾岩为主,含油级别为荧光级以上。根据阿尔奇公式计算出的含油饱和度大部分与实际的含油性相符合,并将含油饱和度70%、50%和38%值作为本区气层、油层、油水层和水层的区分标准。本区储层的含油性受到沉积和构造两方面的控制,沉积作用主要控制储层的岩石结构和物性,构造控制油气的聚集,即在构造高部位,实际含油饱和度比计算结果要高,而在构造低部位,实际含油饱和度比计算结果要低。  相似文献   

Controls on reservoir heterogeneity of tight sand oil reservoirs in Upper Triassic Yanchang Formation in Longdong Area,southwest Ordos Basin,China: Implications for reservoir quality prediction and oil accumulation     

《Marine and Petroleum Geology》2016

Compared to conventional reservoirs, pore structure and diagenetic alterations of unconventional tight sand oil reservoirs are highly heterogeneous. The Upper Triassic Yanchang Formation is a major tight-oil-bearing formation in the Ordos Basin, providing an opportunity to study the factors that control reservoir heterogeneity and the heterogeneity of oil accumulation in tight oil sandstones.The Chang 8 tight oil sandstone in the study area is comprised of fine-to medium-grained, moderately to well-sorted lithic arkose and feldspathic litharenite. The reservoir quality is extremely heterogeneous due to large heterogeneities in the depositional facies, pore structures and diagenetic alterations. Small throat size is believed to be responsible for the ultra-low permeability in tight oil reservoirs. Most reservoirs with good reservoir quality, larger pore-throat size, lower pore-throat radius ratio and well pore connectivity were deposited in high-energy environments, such as distributary channels and mouth bars. For a given depositional facies, reservoir quality varies with the bedding structures. Massive- or parallel-bedded sandstones are more favorable for the development of porosity and permeability sweet zones for oil charging and accumulation than cross-bedded sandstones.Authigenic chlorite rim cementation and dissolution of unstable detrital grains are two major diagenetic processes that preserve porosity and permeability sweet zones in oil-bearing intervals. Nevertheless, chlorite rims cannot effectively preserve porosity-permeability when the chlorite content is greater than a threshold value of 7%, and compaction played a minor role in porosity destruction in the situation. Intensive cementation of pore-lining chlorites significantly reduces reservoir permeability by obstructing the pore-throats and reducing their connectivity. Stratigraphically, sandstones within 1 m from adjacent sandstone-mudstone contacts are usually tightly cemented (carbonate cement > 10%) with low porosity and permeability (lower than 10% and 0.1 mD, respectively). The carbonate cement most likely originates from external sources, probably derived from the surrounding mudstone. Most late carbonate cements filled the previously dissolved intra-feldspar pores and the residual intergranular pores, and finally formed the tight reservoirs.The petrophysical properties significantly control the fluid flow capability and the oil charging/accumulation capability of the Chang 8 tight sandstones. Oil layers usually have oil saturation greater than 40%. A pore-throat radius of less than 0.4 μm is not effective for producible oil to flow, and the cut off of porosity and permeability for the net pay are 7% and 0.1 mD, respectively.  相似文献   

    

Mark E. Johnson  Ellis A. Monash  Michael S. Waterman 《Mathematical Geology》1979,11(1):63-74

Accepted practice dictates that waterflooding of gas reservoirs should commence, if ever, only when the reservoir pressure has declined to the minimum production pressure. Analytical proof of this hypothesis has yet to appear in the literature however. This paper considers a model for a gas-water reservoir with a variable production rate and enhanced recovery with waterflooding and, using an initial dynamic programming approach, confirms the above hypothesis.  相似文献   

油气勘探新领域:火山岩油气藏——松辽盆地大型火山岩气田发现的启示   总被引：9，自引：1，他引：8       下载免费PDF全文

冯志强  刘嘉  王璞琚  陈树民  冯子辉  童英 《地球物理学报》2011,54(2):269-279

通过观念转变和理论与技术创新,大庆油田在松辽盆地徐家围子断陷深层火山岩天然气勘探获得重大突破,使火山岩由原来的油气勘探"禁区"变为"靶区".从而带动了全国的火山岩油气勘探,促使国内油气储量的不断增长.研究表明,各类火山岩均有可能成为良好的储层.与沉积岩相比,火山岩在盆地深层具有体积大、储层物性受埋深影响小、孔渗条件好等...  相似文献   

鲁西隆起区奥陶系碳酸盐岩成岩作用及其对储集性的控制作用   总被引：13，自引：5，他引：8  

张云峰  李忠  王清晨  孔庆友 《地质科学》2005,40(2):207-219

以鲁西隆起区奥陶系碳酸盐岩沉积旋回与不整合面分析为基础, 应用薄片、铸体和阴极发光等室内分析技术, 对其成岩作用、成岩序列、孔隙演化及其特征进行了详细研究。研究区的成岩作用分为两类: 建设性成岩作用和破坏性成岩作用, 前者包括白云石化、压溶、去石膏化、溶蚀和破裂等作用; 后者以重结晶、胶结、压实、硅化和充填作用为主。奥陶系碳酸盐岩经历了多期次和多种类型的成岩作用演化, 与马家沟组相比, 三山子组多经历了一次其沉积后的短期表生和随后的埋藏作用。三山子组白云岩、马家沟组东黄山段、土峪段和阁庄段粉细晶白云岩以及八陡段不整合面以下的溶蚀角砾岩段发育次生孔洞缝系统, 是较为有利的储集层段。  相似文献   

Tectonic and seismic conditions for changes in spring discharge along the Garni right lateral strike slip fault (Armenian Upland)     

Véronique Léonardi  François Arthaud  Achkhen Tovmassian  Arkadi Karakhanian 《Geodinamica Acta》2013,26(2-3):85-103

Abstract

This study presents the relationship between local seismicity and springs discharge, in which the microseismicity modifies the state of stress of the aquifer matrix and these modifications of the local stress control the aquifer behaviour from an example of a basaltic reservoir crossed by a seismic fault.

Along the right-lateral Garni seismic wrench fault, the distribution in space and time of more than 500 micro-earthquakes has been studied providing a pattern of stress distribution. Together with this tectonic survey, the hydrographs of springs issuing from an aquifer located in basaltic lava flows and crossed by the fault have been gauged for 4 years. According to its tectonic, geologic and hydrodynamic properties, the reservoir has been divided in to several parts. The hydrological behaviour of the reservoir and of each of its parts has been modelled, based on the rainfall and hydrodynamic properties of the basaltic reservoir and of nearby reservoirs.

The model allows us to define the ‘normal behaviour’ of the springs, when their discharge is not affected by an earthquake. Anomalies to the normal hydrometric curves are defined, and correlated to small (M < 3.5) earthquakes along the Garni fault. We propose that the circulation of underground water in the area around the fault depends largely on the fracture pattern of the basalts and the aquifer basement, as pointed out from field observations. Changes in spring discharges are explained by variations in the state of stress around the Garni fault, induced by the alternation of elastic strain and stick-slip movement on the fault, and by creep far from the fault. A model of stress distribution is proposed which explains changes in fracture charateristics before and after earthquakes. © Elsevier, Paris  相似文献   

Geochronological Records of Oil-Gas Accumulations in the Permian Reservoirs of the Northeastern Ordos Basin     

CHEN Gang  YANG Fu  LI Shuheng  ZHANG Huiruo  HU Yanxu  LEI Panpan 《《地质学报》英文版》2013,87(6):1701-1711

Geochronology of oil-gas accumulation （OGA） is a challenging subject of petroleum geology in multi-cycle superimposed basins.By K-Ar dating of authigenic illite （AI） and fluid inclusion （FI） analysis combined with apatite fission track （AFT） thermal modeling,a case study of constraining the OGA times of the Permian reservoirs in northeast Ordos basin （NOB） has been conducted in this paper.AI dating of the Permian oil-gas-bearing sandstone core-samples shows a wide time domain of 178-108 Ma.The distribution of the AI ages presents 2-stage primary OGA processes in the Permian reservoirs,which developed in the time domains of 175-155 Ma and 145-115 Ma with 2-peak ages of 165 Ma and 130 Ma,respectively.The FI temperature peaks of the samples and their projected ages on the AFT thermal path not only present two groups with a low and a high peak temperatures in ranges of 90-78℃ and 125-118℃,respectively corresponding to 2-stage primary OGA processes of 162-153 Ma and 140-128 Ma in the Permian reservoirs,but also appear a medium temperature group with the peak of 98℃ in agreement with a secondary OGA process of c.～30 Ma in the Upper Permian reservoirs.The integrated analysis of the AI and FI ages and the tectono-thermal evolution reveals that the Permian reservoirs in the NOB experienced at least 2-stage primary OGA processes of 165-153 Ma and 140-128 Ma in agreement with the subsidence thermal process of the Mid-Early Jurassic and the tectono-thermal event of the Early Cretaceous.Then,the Upper Permian reservoirs further experienced at least 1-stage secondary OGA process of c.～30 Ma in coincidence with a critical tectonic conversion between the slow and the rapid uplift processes from the Late Cretaceous to Neogene.  相似文献   

一个储量可再生的石油地质模型     

崔永强  马广宇  杨丰瑞 《化工矿产地质》2013,(3):157-161,174

最新石油地质基础研究表明,目前正在开采的油气藏可能存在大规模的油气补充,以往勘探地质模型、开发地质模型、三次采油地质模型都没有考虑到储量可增长的因素,可能需要修正。建议国家有关部门设立专项研究,以期为油气勘探开发部署和后期调整提供可靠的地质依据。  相似文献