轮南地区奥陶系原油特征及其控制因素     

王晓梅  张水昌 《海相油气地质》2008,13(3)

轮南地区油气相态分布非常复杂,奥陶系油气藏平面上具有西油东气的特点。西部轮古西油田、塔河油田和轮南1井区油族成熟度略低且有生物降解痕迹,主要以重油形式分布;东部地区油族成熟度略高,主要以轻质油、凝析油形式存在;中间地段桑塔木断垒带、中部平台区和轮南断垒带发生混合作用形成了中一高蜡油。各地区油气在垂向上变化很大,东部地区奥陶系和石炭系为凝析油气,三叠系又为正常油分布区;西部地区奥陶系为稠油,三叠系为正常油。轮南地区奥陶系在纵向上可能受控于岩溶和储层的发育程度,横向上受控于断裂作用。轮南地区油气成藏时间较早,不同物性的原油都是古油藏多期供油的结果。  相似文献   

西藏俄卡地银多金属异常区地球化学     

王铨宇  杨树元 《云南地质》2005,24(3):298-302

异常形态、分布严格受推覆断裂控制,范围大、浓集中心明显,浓度变化及因子载荷表明。区内找Ag、Pb有利,而Sb又为其最佳指示元素。  相似文献   

钻孔灌注桩常见现场事故的分析与防治     

黄跃进 《江苏地质》1997,21(1):47-51

论述了钻孔灌注桩常见现场事故的预防，分析和治理等方面的几个问题，叙述了钢筋笼上浮，导管堵塞，钢筋笼掉入孔内，导管提出混凝土面，掉钻头，串孔等事故的原因和处理方法及预防措施。  相似文献   

雅砻江畔雅江县城区地质灾害特征及其防治对策   总被引：1，自引：0，他引：1  

郑万模  唐小平 《地质灾害与环境保护》1997,8(3):13-20

四川省雅江县城座落于雅砻江河畔。在城区０．８４ｋｍ＾２范围内发育有城南滑坡，城区斜 地面变形、城东危岩和城北滑坡四大地质灾害单元，构成了较为罕见的雅江县城独特的地质灾害特征。论述了雅江县城稆种地质这为害的特征及危害性，并对各咱地质灾害单元按其轻重缓解提出相的防治措施和对策。  相似文献   

Late‐glacial to Holocene depositional architecture of the Ombrone palaeovalley system (Southern Tuscany,Italy): Sea‐level,climate and local control in valley‐fill variability          下载免费PDF全文

Anna Breda  Alessandro Amorosi  Veronica Rossi  Fabio Fusco 《Sedimentology》2016,63(5):1124-1148

The Ombrone palaeovalley was incised during the last glacial sea‐level fall and was infilled during the subsequent Late‐glacial to Holocene transgression. A detailed sedimentological and stratigraphic study of two cores along the palaeovalley axis led to reconstruction of the post‐Last Glacial Maximum valley‐fill history. Stratigraphic correlations show remarkable similarity in the Late‐glacial to early‐Holocene succession, but discrepancy in the Holocene portion of the valley fill. Above the palaeovalley floor, about 60 m below sea‐level, Late‐glacial sedimentation is recorded by an unusually thick alluvial succession dated back to ca 18 cal kyr bp . The Holocene onset was followed by the retrogradational shift from alluvial to coastal facies. In seaward core OM1, the transition from inner to outer estuarine environments marks the maximum deepening of the system. By comparison, in landward core OM2, the emplacement of estuarine conditions was interrupted by renewed continental sedimentation. Swamp to lacustrine facies, stratigraphically equivalent to the fully estuarine facies of core OM1, represent the proximal expression of the maximum flooding zone. This succession reflects location in a confined segment of the valley, just landward of the confluence with a tributary valley. It is likely that sudden sediment input from the tributary produced a topographic threshold, damming the main valley course and isolating its landward segment from the sea. The seaward portion of the Ombrone palaeovalley presents the typical estuarine backfilling succession of allogenically controlled incised valleys. In contrast, in the landward portion of the system, local dynamics completely overwhelmed the sea‐level signal, following marine ingression. This study highlights the complexity of palaeovalley systems, where local morphologies, changes in catchment areas, drainage systems and tributary valleys may produce facies patterns significantly different from the general stratigraphic organization depicted by traditional sequence‐stratigraphic models.  相似文献   

渝东南下古生界页岩构造裂缝形成及分布控制因素          下载免费PDF全文

岳锋  程礼军  焦伟伟  王飞 《地质科学》2016,(4):1090-1100

天然裂缝对页岩气储集和渗流有重要影响,但目前对页岩构造裂缝研究不够深入。本文通过露头、岩心裂缝观察和分析,探讨了渝东南下古生界页岩构造裂缝类型、形成机理及分布控制因素。基于裂缝特征及力学成因,将剪切裂缝分为高角度剪切裂缝、倾斜滑脱裂缝和水平滑脱裂缝。倾斜滑脱裂缝是在上覆岩层重力和水平构造应力共同作用下沿应力集中的软弱面发生剪切滑动形成,水平滑脱裂缝是在构造挤压应力作用条件下主要沿页理面方向的剪切或层间滑动形成;页理发育程度及岩层曲率是控制水平滑脱裂缝形成的关键因素,岩石矿物组成、构造作用及岩层厚度是控制其它类型构造裂缝形成和分布的主要因素,页岩岩石力学层的划分需要根据裂缝特征、岩性变化特征、岩石力学参数及沉积界面等综合确定,岩层厚度与层间构造裂缝密度呈负相关关系。  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   

辽宁西部TM图像逆冲断层解译及找煤研究     

李志兴 《遥感学报》1993,(1)

辽西坳陷中的断陷盆地边缘逆冲断层发育。本文描述了逆冲断层的TM影像特征,解译划分了逆冲断裂带,并指出逆冲断层对找煤远景解译推断的意义。具体分析了南票、北票矿区外围的找煤远景,还应用影像特征探索性地对逆冲断层倾角进行了解译分类。  相似文献   

金沙江流域（云南段）砂金成因类型及其找矿前景     

黄仲权  史清琴 《云南地质》2001,20(3):270-278

根据成矿作用、成矿环境及矿床特征，金沙江流域（云南段）砂金矿床，可划分为：残坡积、洪积、冲洪积、冲积和冰碛等五种类型。成矿主要受碰撞带、深大断裂、大断裂及其派生断裂、基底岩石、地貌、水质和水化学环境等综合控制。以巨甸－大具及中江街－金江街两片区最具有找矿前景。  相似文献   

缅北中部脉金矿带控矿因素及成矿作用浅析     

何文举 《云南地质》2001,20(3):279-288

缅北中部，印缅岛弧及弧后盆地东侧、新生代造山带的前缘推覆构造带中，分布有许多脉金矿床及矿点，构成金矿带。矿带、矿田、矿床及矿体的形成、分布及其规模，受不同级别的近南北向逆冲断裂，及其间派生的北东向张性扩容断裂组成的剪切断裂带控制。可渗透的下麦尔组下部中一粗粒砂岩，起着很好的容矿作用。下麦尔组上部泥岩、细砂岩、粉砂岩和页岩互层单元，在携金热液的迁移、氧化硅的沉淀和矿质沉积定位等方面，可能起到圈闭作用。  相似文献