Effect of igneous activity on hydrocarbon source rocks in Jiyang sub-basin, eastern China

A 50 m thick diabase sill was found in the Paleogene black mudstone hydrocarbon source rocks in Xia38 well. Within heating aureola of the sill, optical changes of kerogen and signatures of extractable bitumens in the mudstones were investigated. Under effects of high heating rate associated with sill intrusion, the vitrinite reflectance (Ro) has an increasing tendency with decreasing distance to the sill both below and above the sill. However, only within a zone of about 15 m to the diabase sill, the vitrinite reflectance shows significant increase. Above the sill, the Ro values increase gradually from 0.6% to 1.0%, whereas below the sill, the Ro values increase dramatically from 0.8% to 3.8%. The contrasting Ro increasing patterns are attributed to the different heat transferring conditions, the relatively open system above the sill and the relatively close system below. The more mature signatures below the sill are also demonstrated by the n-alkane distribution, carbon predominance index and odd-to-even carbon number predominance of the extracted bitumens. Below the sill, the proportion of the saturated hydrocarbons in the extracted bitumens increases from 34% to 79% towards the sill contact. The bitumens in the two highest rank samples which are closest to the sill are dominated by saturated or saturated + aromatic hydrocarbons.The %20S, %αββ and %Ts biomarker parameters of the extracted bitumens are 46%, 58% and 54%, respectively, at Ro = 1.5%. At Ro = 2.6% or 3.0%, they reach to 52%, 71%, and 71%, respectively, still under or close to their corresponding equilibrium end-points. These samples of high rank, established on the basis of optical assessment (vitrinite reflectance), have less mature biomarker signatures. The remarkable disparities between optical and biomarker parameters can be ascribed to that the aromatization of kerogen to increase Ro was more favored than the isomerization of biomarker in the rapid heating scenario.     

Physical and geochemical properties of crude oils in relation to their source rocks,Alif field,Marib Sub-basin,Yemen

Physical and geochemical properties were performed on three crude oils from Alif-01 well in the Marib sub-basin. The analyzed samples comprise medium specific gravity (37^° API), reflecting mature source rocks. The thermal maturity of the analyzed oils is also indicated from the high content of aliphatic hydrocarbons (HC). The compositions of HC further suggest that analyzed oils belong to paraffinic oils. The n-alkane and isoprenoid distributions reveal that the analyzed oils are derived from marine source rock, containing mixed organic matter, with some terrestrial input and deposited under relatively reducing conditions. The features of the analyzed oils are consistent with the Madbi source rock characteristics in the basin.     

苏丹Muglad盆地福北构造-水动力油藏特征和开发经验

福拉凹陷位于苏丹共和国Muglad盆地的东北部,福北油藏位于福拉凹陷中部转换带南部,是一个构造-水动力稠油油藏。该油藏具有埋藏较浅、储集层胶结疏松、高孔隙、高渗透以及底水活跃等特点。依据油藏特点应用"排砂冷采"技术进行开发,并采用与之相配套的完井工艺,包括大口径套管、长沉砂口袋完井和射孔时保护厚油层中的泥岩夹层等,使单井日产量平均超过100m³。在出砂严重井采用"有限排砂"开采技术,降低了作业周期和费用,有效地提高了开发效益。     

山丘区小流域下垫面数据精度对HEC-HMS水文模拟的影响研究

山丘区小流域下垫面条件复杂多变,DEM分辨率及子流域划分水平对分布式水文模型模拟结果的影响有待深入研究。本文选取小流域应用广泛的HEC-HMS分布式水文模型,在河南省栾川流域设置四种DEM分辨率方案及四种子流域划分方案,分别提取不同方案下的流域水文特征参数进行对比,并分析两种类型的数据精度对纳什系数和峰值模拟的影响。研究结果表明,与大中流域相比,DEM分辨率和子流域划分对山丘区小流域空间参数和水文模拟结果的影响要更为显著。在实际山洪预警预报工作中,为保证模拟结果的稳定性和可靠性,应尽可能选择高精度下垫面数据精度。     

四川盆地中二叠统储层特征与勘探方向

近年来,四川盆地中二叠统天然气勘探取得了可喜的进展,多口井在中二叠统茅口组、栖霞组白云岩孔隙型储层段钻获高产工业气流,中二叠统成为该盆地现阶段最现实的接替层系之一。为明确下一步的勘探方向,分析了四川盆地中二叠统的沉积背景和有利储层类型。结果表明：沉积环境主要为开阔台地浅水碳酸盐岩沉积环境;沉积时,古地貌西高东低,中西部生屑滩相储层较东部更为发育;地壳拉张使得中二叠统具备热水沉积、热液改造的良好条件;对勘探有利的3种储层类型为栖霞组滩相白云岩孔隙型储层、茅口组热水白云岩孔隙型储层和茅口组岩溶储层,其中白云岩孔隙型储层是中二叠统最有前景的勘探目标。结论认为：①川西北部—川中地区中二叠统灰质烃源岩生烃强度大,具有形成大中型气田的物质基础;②川西地区栖霞组白云岩储层较厚,是中二叠统天然气勘探的最有利地区;③上述3种储层类型均发育的地区主要分布在川中地区,其3套储层纵向上叠置,勘探潜力大;④剑阁—南充—丰都地区位于热次盆区带,其茅口组热水白云岩储层发育且叠加茅口组岩溶储层,天然气勘探前景好。     

四川盆地中二叠统热水白云岩成因及其分布

四川盆地油气勘探过程中,在钻揭中二叠统时常发现厚度不等的白云岩储层,但过去对该套储层的特征、成因机制、分布规律等认识不一致,制约了其勘探进程。为此,在系统分析川东地区该套白云岩储层的岩性特征和储集空间类型,以及基底断裂对中二叠统沉积影响的基础上,初步落实了该区中二叠统茅口组茅二a亚段白云岩储层的平面分布范围;进而探讨了白云岩储层的成因机制,并提出了热次盆、热次盆沉积微相的概念。结论认为:1茅二a亚段层状白云岩储层厚度可达30m,以细—中晶、硅质白云岩为主,其溶蚀孔洞、裂缝发育,储集性能好;2地球化学特征分析结果表明,茅二a亚段白云岩为热水成因沉积(非正常海水水成沉积),基底断裂控制了该套白云岩储层的平面展布;3过去认为该区W67、W83、W93等3口井因钻遇特大裂缝系统从而造就了石灰岩储层高产,而此次研究则证实,这3口井均属同一压力系统,高产原因在于其储层均为茅二a亚段白云岩储层;4热次盆沉积微相为川东地区茅口组最有利的储集相带,勘探工作应围绕这一沉积微相的分布范围展开。     

澳大利亚Vulcan次盆Puffin油田油气源与成藏

Puffin油田目前油气来源不明,主力烃源岩展布及主要生、排烃期不确定都制约了下一步勘探的进行。利用烃源岩二维生烃模拟以及生物标志物指纹对比等方法,揭示了下Vulcan组海相泥页岩是本区最为重要的一套烃源岩,白垩纪-中新世为主要生、排烃期;而本区的Plover组烃源岩普遍演化程度较高,在晚侏罗世已达到高成熟,生烃潜力差,对于成藏的贡献较为有限,属于次要烃源岩。成藏事件图反映出Puffin垒带上的圈闭主要形成于侏罗纪-白垩纪,中新世以前由于侏罗系以上地层断裂不发育,下Vulcan组主力烃源岩生成的原油主要在地堑中的侏罗系圈闭中聚集成藏。中新世末,区域性的构造挤压运动形成众多垂向断裂并且使早期形成的断裂体系活化,使得早期成藏的油气垂向调整到浅层的白垩系聚集成藏。因此,目前Puffin油田发现的白垩系油藏主要为次生油藏,为早期侏罗系油藏调整改造到浅部垒带上形成。     

苏丹福拉凹陷陡坡带构造地质特征及勘探

福拉凹陷区域地质上属于在中非剪切带应力场背景下拉张形成的被动裂谷凹陷,整体呈西断东超的箕状凹陷,西部陡坡带为一个受长期活动的边界断层控制的一个狭长区域,面积约400 km2.该构造带具有构造复杂,地层产状陡,沉积相变化快等特点,因而在地震采集和处理技术、石油地质综合评价和钻井作业技术方面面临一系列挑战.综合地质研究及勘探实践证实,对于复杂断块油气田,及早部署三维地震采集以落实复杂构造并采用滚动勘探开发的思路,可以快速、有效地探明储量规模,减少失误.提高勘探效益;针对不同的地下及地表条件,优化采集参数和接收组合,并在构造主体部位采用加密炮线增加局部覆盖次数,有利于改善地震资料品质;适时调整钻井工程技术,可有效地提高钻探效率和井身质量,有利于油层的发现和储集层保护.     

基于GIS技术的方便水库面源污染控制方案研究

以南京市溧水区方便水库为研究对象,运用GIS技术并结合RS技术对整个汇水区域进行污染源的解析,确定污染关键因素以及重点污染区域,在此基础上,提出符合该水源地现状的最优保护方案。结果表明:在整个汇水区域中,耕地面积所占比例最大,且主要集中在青龙桥河、谢家棚河和西南村河3个水库主要来水河流流域内。青龙桥河和谢家棚河流域是污染负荷排放量最大的区域,其次是西村河和西南村河流域。在兼顾污染物去除率和成本的前提下,生态沟渠-生态塘技术是最优农田径流污染控制技术,其次为生态拦截缓冲带技术;生物接触氧化-人工湿地处理技术是农村生活污水最优控制技术。     

NUMERICAL MODELLING OF THE AUSTRALIA – ANTARCTICA CONJUGATE MARGINS USING THE GALO SYSTEM: PART 1. THE BREMER SUB-BASIN,SW AUSTRALIA

An analysis of variations in the tectonic subsidence of the Bremer sub-basin (offshore SW Australia) since 160 Ma using the GALO numerical basin modelling programme has made it possible both to refine previous models and to estimate the intensity of stretching and thermal activation of the lithosphere. The new model explains the rapid subsidence of the sub-basin and the deposition of the synrift Bremer 1 unit during the initial rift phase in the Late Jurassic (160 to 130 Ma). This phase of extension was accompanied by high heat flows, typical of the axial zones of continental rifts, and lithospheric stretching with a β-factor of about 1.4. Between 130 and 43 Ma, the abnormally low depositional rate and the shallow water depths suggest moderate thermal activation of the mantle and the absence of extension-driven subsidence. However during the Eocene (43 to 37 Ma), the modelling suggests that another phase of intense stretching of the sub-basin lithosphere took place with β = 1.7, explaining both the subsidence and an abrupt increase in water depth from about 50–200 m to nearer 2000 m. The high heat flows during the initial stage of rifting and thermal activation during Cenozoic extension contributed to the early generation of hydrocarbons by source rocks in the Bremer 1 unit at the base of sedimentary cover. At the present day, these source rocks are overmature. At the same time, the modelling suggests that generation of light and heavy oil in the overlying Bremer 2 and 3 units has occurred. Source rock intervals in the upper half of the Bremer 3 unit and in the overlying successions are early mature or immature and may have generated minor volumes of hydrocarbons.