Distribution of the Ordovician Fluid in the Tahe Oilfield and Dynamic Response of Cave System $48 to Exploitation     

LOU Zhanghua  ZHU Rong  YUN Lu  RAN Qihua  SU Danyang  LI Mei 《《地质学报》英文版》2008,82(3)

The Tahe Oilfield is a complex petroleum reservoir of Ordovician carbonate formation and made up of spatially overlapping fracture-cavity units. The oilfield is controlled by a cave system resulting from structure-karst cyclic sedimentation. Due to significant heterogeneity of the reservoir, the distribution of oil and water is complicated. Horizontally, a fresh water zone due to meteoric water can be found in the north part of the Akekule uplift. A marginal freshening zone caused by water released from mudstone compaction is found at the bottom of the southern slope. Located in a cross- formationai flow discharge zone caused by centripetal and the centrifugal fows, the main part of the Tahe Oilfield, featuring high salinity and concentrations of CI- and K Na , is favorable for accumulation of hydrocarbon. Three types of formation water in the Tahe Ordovician reservoir are identified: (1) residual water at the bottom of the cave after oil and gas displacement, (2) residual water in fractures/pores around the cave after oil and gas displacement, and (3) interlayer water below reservoirs. The cave system is the main reservoir space, which consists of the main cave, branch caves and depressions between caves. Taking Cave System $48 in the Ordovician reservoir as an example, the paper analyzes the fluid distribution and exploitation performance in the cave system. Owing to evaporation of groundwater during cross-formational flow, the central part of the main cave, where oil layers are thick and there is a high degree of displacement, is characterized by high salinity and Brconcentration. With high potential and a long stable production period, most wells in the central part of the main cave have a long water-free oil production period. Even after water breakthrough, the water content has a slow or stepwise increase and the hydrochemistral characteristics of the produced water in the central part of the main cave are uniform. From the center to the edge of the main cave, displacement and enrichment of oil/gas become weaker, residual water increases, and the salinity and concentration of Br- decrease. At the edge of the main cave, although the wells have a high deliverability at the beginning with a short stable production period and water-free production period. After water breakthrough, the pressure and deliverability drop quickly, and the water content rises quickly. The hydrochemistrai characteristics of the produced water are relatively uniform. Wells in the branch caves have a relatively low deliverability at the beginning, with a short stable production period. Water breakthrough appears quickly and then the pressure and deliverability drop quickly. The salinity and concentrations of CI-and K Na are usually fluctuant or descend slowly in the produced water. Wells in low areas of ancient karst have a low deliverability and a short stable production period. The yield drops quickly and the water content is high, while the characteristics of the produced water may vary significantly well to well. The salinity and concentrations of CI- and K, Na in the produced water are usually fluctuant with a precipitous decline.  相似文献   

Iodine-129 chronological study of brines from an Ordovician paleokarst reservoir in the Lunnan oilfield,Tarim Basin     

《Applied Geochemistry》2016

Previous studies have shown that brines in an Ordovician paleokarst reservoir of the Lunnan oilfield in the Tarim Basin, China, are the product of mixing of paleo-evaporated seawater in the east with paleometeoric waters in the west. In order to put time constraints on the brine and related hydrocarbons in this field, 10 brine samples were collected, for which the iodine concentrations and ¹²⁹I/I ratios were measured and discussed. The iodine concentration (3.70–31.2 mg/L) and the ¹²⁹I/I ratio (189–897 × 10⁻¹⁵) show that the iodine in the paleoseawater and meteoric water (MW) had different origins and ¹²⁹I characteristics. The paleoseawater has a high iodine content (∼31 mg/L), indicating that iodine was introduced into the reservoir along with thermally generated hydrocarbons, possibly in the Cretaceous, from the Caohu Sag in the eastern area. Based on consideration of all possible origins of iodine and ¹²⁹I in the brines, it is suggested that the meteoric water maintained its initial iodine content (0.01 mg/L) and ¹²⁹I/I ratio (1500 × 10⁻¹⁵), whereas the iodine-enriched paloseawater (IPSW) exhibited a secular ¹²⁹I equilibrium (N_sq = 39 atom/μL) as a result of fissiogenic ¹²⁹I input in the reservoir over a long period of time. The model of brine evolution developed on that basis confirmed that meteoric water entered the reservoir in the Miocene at about 10 Ma, and partially mixed with the iodine-enriched paleoseawater. The movement of meteoric water was facilitated by faults created during the Himalayan orogeny, then became more dense after dissolving Paleogene halite and infiltrated into the reservoir at high pressure. The iodine and ¹²⁹I concentration in the brine contains information about the path and history of the fluid in the reservoir. This may be useful in oil exploration, since the movement of water was, to some extent, related to hydrocarbon migration.  相似文献   

胜利油田近海及沿岸地区东北大风及风暴潮分析预报   总被引：1，自引：0，他引：1  

田林生 《海洋预报》2002,19(1):73-80

对产生影响胜利油田近海及沿岸地区东北大风及风暴潮灾害的两大类天气系统进行了具体分析，分别给出了冷锋配合江淮气旋产生东北大风及风暴潮的三种环流形势和两类影响胜利油田热带气旋移动路径及其预报着眼点。  相似文献   

孤岛油田南区东部曲流河沉积结构单元分析     

冯伟光 《海洋地质译丛》2008,(3):31-35

曲流河储层是我国石油资源的重要载体，但是目前研究主要还停留在微相级别，叠置点坝的划分对比研究还稍显薄弱。研究利用“层次分析”方法，通过分析河道砂体顶面高程差、出现不连续河间砂体、过井地震剖面的波形差异、平面上的砂体厚度差异等四个方面，有效地在复合河道中划分出单一河道。通过对砂体垂向沉积层序、砂体厚度分布及废弃河道位置的分析可以识别出点坝沉积；利用“砂顶泥岩厚度法”可以快速识别地下废弃河道，确定点坝沉积的边界；根据Leeder计算河流满岸宽度经验公式及点坝长度与河流满岸宽度的相关公式可以确定点坝沉积的规模。  相似文献   

靖安油田盘古梁长6油藏地质建模研究   总被引：1，自引：0，他引：1  

赵惊蜇  闰林  孙卫  梁晓伟  解伟 《地球科学与环境学报》2007,29(2):162-165

建立能正确反映靖安油田盘古梁长6油藏地质特征的地质模型,通过对地层格架、沉积微相、骨架砂体、物性参数和储层非均质性的分析研究,借助GMSS地质建模软件,建立了确定型精细三维地质模型。所建立的构造、砂体、属性参数模型对该油藏的地质特征有了进一步认识,为油藏的高效开发提供了依据。  相似文献   

环江油田巴19区块长7段钙夹层评价与大斜度井分段压裂优化          下载免费PDF全文

宋景远  姚谋  景文平  刘圣战  毛冠华  张恒  季长伟 《探矿工程》2021,48(10):29-35

为实现最大化油藏接触,提高油藏产出水平,长庆环江油田巴19区块长7油藏采用大斜度井开发方式。在初期压裂改造中,由于忽视了层内钙质夹层对压裂缝高的影响,导致实际裂缝的几何形态与设计产生巨大偏差,出现了邻井裂缝串通及生产高含水等问题。本文通过研究油藏剖面测井特征,在细分层位基础上分析纵向应力分布,研究“复合层效应”影响裂缝缝高延伸的关键因素,优化了分段压裂方案,获得了更好的水力裂缝几何形态和尺寸。技术调整后现场压裂工艺质量获得提高,长7段油藏压裂改造质量优良率100%,大大提高了该区块的开发水平。  相似文献   

渤中34-9油田储层敏感性评价          下载免费PDF全文

陈建宏  魏飒飒  余建生  王志超  赵海建  陈龙 《探矿工程》2021,48(9):111-118

渤中34-9油田为我国海上首个火成岩发育区的大型油田,油田位于渤中34围区,其主要目的储层为东三段和沙河街组。为加强油田储层保护,提高油气产量,本文通过分析储层岩性特征、孔渗特征和流体特征,对储层岩心进行速敏、水敏、盐敏、碱敏和酸敏储层敏感性评价,进而直观、定量地评价该油田储层损害因素,并针对性地提出预防和减少储层侵害的合理化建议,对渤中区块储层保护工作具有重要的现实意义。  相似文献   

古河道储层构型层次分析法——以弧岛油田馆陶组曲流河为例     

岳大力  王军王延忠吴胜和  刘建民束青林 《地质科学》2010,45(3):832-843

以胜利油区孤岛油田11J11密井网区曲流河储层为例,在曲流河野外露头和现代沉积原型模型研究成果的基础上,应用岩心、测井及动态等资料,探索了一套曲流河地下储层构型分析方法。在基于构型分析的精细等时地层对比及单井构型要素解释的基础上,采用“层次分析”和“模式拟合”的研究思路,按复合曲流带、单一曲流带、单一点坝以及点坝内部侧积体的4个层次进行模式拟合,对曲流河各级次构型单元内部结构进行系统分析。拟合结果既符合曲流河沉积成因理论,又与研究区动态资料吻合,说明研究成果是可靠的,由此建立了真正意义上的三维储层构型模型,再现了曲流河点坝内部泥质侧积层空间分布特征,为分析油田开发后期储层构型控制的剩余油分布规律提供了科学依据,该方法对类似油田精细储层研究有较好的借鉴作用,并能推广应用。
  相似文献   

准噶尔盆地乌尔禾油田百口泉组冲积扇沉积特征及油气勘探意义   总被引：7，自引：1，他引：6  

宫清顺  黄革萍  倪国辉  孟祥超  丁梁波 《沉积学报》2010,28(6):1135-1144

通过分析岩心、铸体薄片及测井等资料,认为准噶尔盆地乌尔禾油田百口泉组发育一套典型的退积型冲积扇沉积。百口泉组中下部发育扇中亚相,上部发育扇缘亚相,反映研究区在三叠纪早期,湖平面逐渐升高,可容空间与沉积物补给速率比值（A/S比值）逐渐增大的沉积特征。沉积微相类型包括辫状河道充填、筛状沉积、泥石流沉积及片流沉积。综合构造、测试及试油等资料,认为扇中亚相辫状河道充填为油气富集的有利储集相带,控制了油气富集的规模与油藏边界。在有利相带控制油藏分布的结论指导下部署钻探的多口评价井在百口泉组均获得工业油流,有效地指导油田现场生产。  相似文献   

黄河水下三角洲海底管线差异沉降的安全性分析     

常方强  贾永刚 《中国海洋大学学报(自然科学版)》2009,39(2)

针对胜利油田埕岛海域海床土体强度的非均匀性和可能引起的海底管线差异沉降破坏,提出1种海底管线差异沉降安全性分析方法.具体介绍差异沉降产生的原因,通过分析管线的受力状态,建立管线因差异沉降引起的附加应力的表达式.针对黄河水下三角洲埕岛油田常见的3种规格管线,建立不同土质条件下的管线附加应力表格,方便工程师查询.考虑附加应力和流体对管线的应力,与管线材料的允许应力比较,可以判断管线的安全性.  相似文献