冀中坳陷深县凹陷东营组砂岩储层特征及影响因素

冀中坳陷深县凹陷东营组砂岩储层岩石类型以长石岩屑砂岩或岩屑长石砂岩为主,岩石成分成熟度和结构成熟度均较低,反映了近物源和多物源的特征。通过对研究区的岩心化验分析资料、薄片和扫描电镜资料的分析,认为深县凹陷东营组储集空间类型主要包括原生孔隙和次生孔隙两类,其中以原生的粒间孔隙为主。研究区岩性孔渗资料的统计结果表明,储层的物性较好,基本为中高孔中渗型储层,根据深县凹陷储层评价标准,可以将深县凹陷储层分为4类,东营组储层主要是Ⅰ类和Ⅱ类储层。深县凹陷东营组主要为辫状河流相沉积,其沉积作用直接决定着储集砂体的类型、展布范围以及后期成岩改造作用。而储层储集性能主要受原始沉积作用及后期成岩作用共同控制,控制储层孔隙演化的成岩作用主要为机械压实作用和胶结作用。     

中国海域基岩油气藏特征及未来勘探方向

基岩油气藏是一种特殊类型的油气藏。随着渤中19-6凝析气藏、永乐8-3-1基岩油气藏及渤中13-2油气田等取得重大突破,证实中国海域基岩油气藏具有巨大勘探潜力。截至目前,已在渤海盆地、北部湾盆地、琼东南盆地、珠江口盆地获得多个高产基岩油气田。中国海域基岩油气藏具有分布广泛、纵向层系多、岩性多、类型多样的特征,主要发育前寒武系变质岩和混合花岗岩、古生代碳酸盐岩、中生代火山岩以及花岗岩侵入体、中生代碎屑岩等4套储层,尤其以前寒武系变质岩和中生代花岗岩侵入体为主。研究表明基岩油气藏主要表现为新生古储,其形成主要受控于富烃凹陷、构造运动、储盖条件等多种控制因素的影响。在总结前人成果的基础上,指出了中国海域未来基岩油气藏勘探应重点关注6大勘探方向：渤海盆地残山,北黄海盆地东部坳陷东北部局部凸起,南黄海盆地凸起带,东海陆架盆地低凸起,北部湾盆地涠西南凹陷、珠江口盆地惠州凹陷和琼东南盆地松南低凸起,南海南部中建南盆地和万安盆地。     

Effects of structural segmentation and faulting on carbonate reservoir properties: A case study from the Central Uplift of the Tarim Basin,China

The largest condensate field of the Ordovician reef-shoal reservoirs, in China, was discovered along the N°1 fault zone in the Tarim Basin. However, current drilling activities are hindered by the low and unstable production from these carbonate reservoirs. A detailed structural analysis of 3-D seismic data identified three segments along the N°1 fault zone characterized by differences in structural geometry and evolution. Segmentation of the N°1 fault zone has resulted in the variation of characteristics and distribution of the Upper Ordovician carbonate reservoirs. Due to fault induced differential uplift before the Late Ordovician, a narrow and thick-rimmed platform margin rich in reefs has developed in the eastern segment, whereas wider and thinner shoals developed in the central and western segments. We clearly identified a fault block uplift related erosional unconformity, and associated karstification at the top of the Upper Ordovician carbonates in the eastern segment. In this segment, the karst caves resulted in the high and stable hydrocarbon production. In the central segment, good matrix reservoirs exist, but due to the lack of fault-related enhancement of the reservoirs quality, only relatively low production is observed. In the western segment, where fracture-vug reservoirs occurred in relation to later fault damage zones, production is much greater but unstable. Large-scale fracture-caves reservoirs related to fault activity, rather than the good unfaulted matrix reservoirs, lead to the high production of oil and gas. We classify these reef-shoal reservoirs as faulting modified reservoirs. Further exploitation should focus more on the fault damage zone beyond the platform margin rather than the microfacies in the Lower Paleozoic carbonates.     

辽河坳陷兴隆台油田成藏特征与成藏模式

利用地球化学、地质资料对辽河坳陷兴隆台地区的成藏特征进行了系统研究,认为研究区具有多油源供烃、多类型输导、多期次充注的特点。油源对比研究表明,油气主要来源于清水洼陷,其次为陈家洼陷,其中清水洼陷沙三段为主要烃源岩。含氮化合物指示油气沿着断层、砂体、不整合面等多种输导体,从生烃洼陷向构造高部位进行运移。流体包裹体与烃源岩生烃史显示研究区发生了多期成藏,主要成藏期为东营末期。综上,建立了以下3种成藏模式:潜山油气藏的"单源供烃、断层-不整合输导、早期成藏模式",沙三段油气藏的"自生自储、断层-浊积砂输导、早期成藏模式"和浅层沙二段、沙一段、东营组油气藏的"多源供烃、断层-砂体输导、晚期成藏模式"。     

叠前地震反演在清水地区砂砾岩优质储层预测中的应用

辽河坳陷清水地区沙一段广泛发育了扇三角洲砂砾岩沉积,与同期沉积的暗色泥岩形成了良好的生储盖组合,是寻找岩性油气藏的有利地区。沙一段主要储层为含砾砂岩、细砂岩,受含灰质成分影响,含灰泥岩、含灰粉砂岩等非储层与储层的波阻抗相互重叠,利用常规叠后波阻抗反演无法准确预测优质储层。基于岩石物理分析,指出λρ和μρ为识别优质储层的敏感弹性参数。在叠前道集优化处理和横波预测的基础上,通过叠前地震反演得到λρ和μρ,对扇三角洲砂砾岩优质储层的分布特征进行了预测,为清水地区砂砾岩岩性油气藏勘探提供了依据。     

惠民凹陷江家店地区滩坝砂岩特征与储层预测

惠民凹陷江家店地区沙四上亚段沉积时期广泛发育滨浅湖滩坝砂体沉积,油气资源丰富。滩坝砂岩具有砂泥互层、单砂层厚度薄、横向变化快等特点,增大了滩坝砂岩储层的地震识别与预测难度。通过分析滩坝砂岩与古地形、古沉积环境等因素的关系,综合应用录井、测井、地震相分析和多属性融合等技术对滩坝砂体进行有效识别,指导了该区油气勘探实践。     

Diagenetic differences caused by the charging of natural gases with various compositions - a case study on the lower Zhuhai Formation clastic reservoirs in the WC-A sag,the Pearl River Mouth Basin

Only a limited number of comparative studies have explored the diagenetic differences of reservoirs caused by the charging of natural gases with different compositions during the migration and accumulation of oil and gas. In this study, we quantitatively assessed the diagenetic variations of the lower Zhuhai Formation reservoirs in the WC-A sag, the Pearl River Mouth Basin, as a result of natural gas charging with different compositions. The employed methods included electron microscopy, scanning electron microscopy, cathode luminescence, X-ray diffraction, chemical composition analysis of formation water, stable isotope analysis, and fluid inclusion determination. The results indicated that: (1) in the lower Zhuhai Formation reservoir that are near the large fractures, the late-charging of CO₂-rich thermal fluid promoted the dissolution of minerals, and changed the porosity, permeability, pH value of fluid, and the contents of ions such as K⁺, Na⁺, Mg²⁺ of the reservoirs. These changes, in turn, indirectly affected the content, form, and distribution of clay minerals in the reservoirs. In addition, the secondary enlargement of quartz was enhanced. (2) The charging of CO₂-rich thermal fluid caused strong dissolution and produced high contents of cements. The dissolution mainly occurred in a half open system with strong fluid activity. Consequently, the significantly decreasing of permeability was hindered and middle porosity–middle permeability reservoirs were generated. The reservoirs that are far from the large fractures, however, were mainly early charged by the hydrocarbon-rich fluid. The dissolution was weak and the generated cements were limited. In addition, the dissolution products could not be discharged in such closed diagenetic systems. As a result, the permeability of the reservoir was declined sharply and resulted in low porosity–low permeability reservoirs.     

Defining the 3D geometry of thin shale units in the Sleipner reservoir using seismic attributes

Defining the 3D geometry and internal architecture of reservoirs is important for prediction of hydrocarbon volumes, petroleum production and storage potential. Many reservoirs contain thin shale layers that are below seismic resolution, which act as impermeable and semi-permeable layers within a reservoir. Predicting the storage volume of a reservoir with thin shale layers from conventional seismic data is an issue due to limited seismic resolution. Further, gas chimneys indicative of gas migration pathways through thin shale layers, are not easily defined by conventional seismic data. Additional information, such as borehole data, can be used to aid mapping of shale layers, but making lateral predictions from 1D borehole data has high uncertainty. This paper presents an integrated workflow for quantitative seismic interpretation of thin shale layers and gas chimneys in the Utsira Formation of the Sleipner reservoir. The workflow combines the use of attribute and spectral analysis to add resolution to conventional seismic amplitude data. Detailed interpretation of these analyses reveals the reservoirs internal thin shale architecture, and the presence of gas chimneys. The comprehensive interpretation of the reservoirs internal structure is used to calculate a new reservoir storage volume. This is done based on the distribution of sand and interpreted shale layers within the study area, for this active CO₂ storage site.     

长岭坳陷腰英台油田青山口组油气成藏主控因素分析

腰英台油田区是松辽盆地南部近几年发现的具有超亿吨级储量规模的大型含油气区。结合勘探实践对腰英台地区青山口组油气成藏条件分析表明,油气成藏的主控因素包括烃源、储层和输导三个方面。油气成藏主要围绕乾安次凹生烃中心,烃源岩控制油藏的聚集与分布;断裂一方面作为输导体系,另一方面控制着不同类型油藏的平面分布;沉积微相控制砂体的平面分布以及砂体的储集物性。最终指出了近源带、断裂带、砂体发育带三者叠置区是下步勘探的有利方向。     

建南气田含气碳酸盐岩的AVO正演模拟

建南气田的主要产气层是三叠系飞仙关组、二叠系长兴组和石炭系黄龙组海相碳酸盐岩储集层。在综合测井和地质资料的基础上,对碳酸盐岩储层进行AVO正演模拟,总结出目的层主要为第3类AVO异常响应特征,为AVO方法在检测碳酸盐岩地层的含气性提供指导作用。     

复杂岩性油田油气层综合评价——以XX29-2油田为例

XX29-2油田为复杂岩性油田,在近物源快速沉积背景下,储层岩性、物性变化快,纵向上为多期砂体叠置,平面上砂体相变快,非均质严重。根据岩心观察、岩石薄片鉴定、扫描电镜等资料,首先对XX29-2油田基础资料丰富的层段进行岩性识别,再利用岩矿与测井的结合,识别出无岩心、壁心等资料的层段,最终识别出研究区的岩性。又因XX29-2油田储层岩电特征复杂,电阻率测井受岩性影响较大,单纯依靠测井曲线识别油层和储层亦较困难,首先通过压汞、孔渗等资料结合岩性和沉积相对储层分类,再参考岩性、测井资料确定界限层,接着合理选择界限层进行测试,最后结合核磁共振等资料,综合识别该区的油层和储层。这种识别储层和油层的方法为渤海油田在复杂岩性中识别储层和油层提供了技术借鉴。     

涠洲11-1油田角尾组低阻油藏成因机理及测井评价方法

涠洲11-1油田角尾组二段油层普遍具有低电阻率特征,在复杂的地质条件下使得低阻油层与水层的识别难度增大,为此,利用岩心分析化验、录井、测井、构造及试油等资料,从宏观和微观地质因素入手,对该区低阻油层成因机制进行了系统深入的剖析。结果表明,角尾组低阻油层的主要宏观地质成因是构造和沉积特征,它们共同为涠洲11-1地区低阻油层的形成和分布创造了条件;微观低阻成因是在水动力条件较弱的滨海沉积环境下发育的岩性粒度细、泥质含量高、黏土矿物附加导电性以及低幅度构造背景下的高束缚水饱和度所致。在此基础上,结合成因提出了改进后的自然伽马相对值与视地层水电阻率的交会图、改进后的自然电位相对值与深感应电阻率的交会图以及束缚水饱和度—视地层水电阻率的交会图来综合识别低阻油层,结果表明,该方法显著提高了低阻油层的识别能力,展示出良好的应用前景。     

Elastic-wave velocity characterization of gas hydrate-bearing fractured reservoirs in a permafrost area of the Qilian Mountain,Northwest China

There are two types of gas hydrate-bearing reservoirs in the permafrost area of Qilian Mountain. Most of the gas hydrates occur mainly in the fractured mudstone reservoirs and rarely in the pores of the sandstone reservoirs. In this study, for the acoustic velocity characterization of the fractured gas hydrate reservoirs of the Qilian Mountain permafrost area, some mudstone core samples were collected for physical rock experiments, such as the acoustic experiment and the porosity and permeability experiment. An acoustic velocity numerical simulation of gas hydrate reservoirs was performed according to the Biot theory and the differential effective medium theory, with the conditions of multiple gas hydrate occurrence models, including the suspension model, the semi-cementation model and the cementation model, and considering both infinite and penny-shaped cracks. Fracture porosity was added to the core samples that only contain matrix porosity. With fracture porosity ranging from 0.01% to 5%, the variation laws between acoustic velocity with fractured porosity and hydrate saturation are obtained: (1) In the case of an infinite crack, if the fractured porosity is 0.01%–1%, the P-wave velocity decreases rapidly in the case of the three occurrence models. If the fractured porosity is higher than 1%, the acoustic velocity decreases gradually. If the crack shape is a penny-shaped crack, the P-wave velocity decreases almost linearly with increasing fracture porosity. (2) If the hydrate occurrence model is the suspension model, the P-wave velocity increases slightly with increasing hydrate saturation. If the occurrence model is the semi-cementation model or the cementation model, when the gas hydrate saturation of the infinite crack ranges from 0 to 80%, the acoustic velocity increases approximately linearly, whereas when the gas hydrate saturation ranges from 80% to 100%, the velocity increases rapidly. If the crack is a penny-shaped crack, the velocity increases almost linearly with increasing gas hydrate saturation from 0 to 100%. (3) It is found that the fractured gas hydrate reservoirs of the Qilian Mountain permafrost area contain both penny-shaped and infinite cracks, of which the infinite crack is the main crack shape. The gas hydrate occurrence in the Qilian Mountain permafrost area mainly follows the suspension model. This has significance for the seismic exploration and log evaluation of gas hydrate-bearing fractured reservoirs in the permafrost area of the Qilian Mountain in studying the acoustic velocity characterization, the crack shapes and occurrence models of gas hydrate reservoirs in the study area.     

Controlling factors on the charging process of oil and gas in the eastern main sub-sag of the Baiyun Sag,Zhujiang River (Pearl River) Mouth Basin

The eastern main sub-sag (E-MSS) of the Baiyun Sag was the main zone for gas exploration in the deep-water area of the Zhujiang River (Pearl River) Mouth Basin at its early exploration stage, but the main goal of searching gas in this area was broken through by the successful exploration of the W3-2 and H34B volatile oil reservoirs, which provides a new insight for exploration of the Paleogene oil reservoirs in the E-MSS. Nevertheless, it is not clear on the distribution of “gas accumulated in the upper layer, oil accumulated in the lower layer” (Gas_upper-Oil_lower) under the high heat flow, different source-rock beds, multi-stages of oil and gas charge, and multi-fluid phases, and not yet a definite understanding of the genetic relationship and formation mechanism among volatile oil, light oil and condensate gas reservoirs, and the migration and sequential charge model of oil and gas. These puzzles directly lead to the lack of a clear direction for oil exploration and drilling zone in this area. In this work, the PVT fluid phase, the origin of crude oil and condensate, the secondary alteration of oil and gas reservoirs, the evolution sequence of oil and gas formation, the phase state of oil and gas migration, and the configuration of fault activity were analyzed, which established the migration and accumulation model of Gas_upper-Oil_lower co-controlled by source and heat, and fractionation controlled by facies in the E-MSS. Meanwhile, the fractionation evolution model among common black reservoirs, volatile reservoirs, condensate reservoirs and gas reservoirs is discussed, which proposed that the distribution pattern of Gas_upper-Oil_lower in the E-MSS is controlled by the generation attribute of oil and gas from source rocks, the difference of thermal evolution, and the fractionation controlled by phases after mixing the oil and gas. Overall, we suggest that residual oil reservoirs should be found in the lower strata of the discovered gas reservoirs in the oil-source fault and diapir-developed areas, while volatile oil reservoirs should be found in the deeper strata near the sag with no oil-source fault area.     

Pliocene basin-floor fan sedimentation in the Bay of Bengal (offshore northwest Myanmar)

This study addresses reservoir development and hydrocarbon occurrence of the late Pliocene basin-floor fan deposits in the northeastern Bay of Bengal. The G-series turbiditic sandstones host dry gases, biogenic in origin, of three gas fields that are juxtaposed on the western flank of the NW–SE anticline. The gas reservoirs are stacked in back-stepping fashion being sourced from northwest as part of the Bengal fan. The Shwe field (Shwe fan) has an elongate fan-shaped morphology (12 km long and 4 km wide) and occurs about 30 km off the base of slope.The Shwe field reservoirs consist of two contrasting types of turbidite deposits, lower G5.2 and upper G3.2 reservoirs. The G5.2 is characterized by stacked lobe elements in which amalgamated and layered sheet sandstones provide an excellent vertical connectivity and high net-to-gross ratio (avg. 86%). On the contrary, the G3.2 represents overbank deposits, which is characterized by thin-bedded sandstones with low net-to-gross ratio (avg. 33%) as well as low-resistivity pays.Aside from the primary depositional framework, post-depositional modifications appear to have greatly affected Shwe fan, adding complexity in establishing a geological model. A line of evidence suggests that G5.2 lobe sands were injected into overlying G3.2, mostly in the form of sills. The injected sand beds measured from G3.2 cores account for 10 m, more than half of the total net sand. The sand injection is thought to be triggered by slumping that overpressured G5.2 lobes. Post-G3.2 erosional channel complexes incised into G5.2 and G3.2, ultimately diminishing gas pool extent as well as dividing Shwe fan into multiple compartments.     

渤中凹陷428构造中生界火山岩优质储层主控因素

渤海湾盆地中生界火山岩广泛发育,岩性变化快,储层非均质性强,优质储层主控因素认识不清。为探索火山岩优质储层控制因素,充分利用岩芯、薄片、实验等数据,系统分析了研究区火山岩储层岩性特征、储集空间特征及储层控制因素。分析表明：研究区火山岩主要发育安山岩、玄武岩、火山角砾岩和凝灰岩4种岩石类型,储集空间类型为“裂缝-孔隙型”。火山岩优质储层主要受岩性岩相、旋回界面和构造运动共同控制,其中岩性岩相控制了火山岩优质储层的纵向分布,旋回界面控制了火山岩优质储层的垂向分布,构造运动可以对火山岩储层进行再改造。     

南海北部气烟囱成因及其与油气及水合物运聚成藏关系

南海北部大陆边缘盆地油气勘探及天然气水合物调查与勘查评价中,地球物理资料尤其是二维/三维地震剖面上常见不同类型、不同特征且与油气藏及天然气水合物藏密切相关的地震反射模糊带等地震地质异常体,即“气烟囱”或“流体底辟”或“含气陷阱”。本文拟重点研究“气烟囱”成因及其与油气及天然气水合物运聚成藏的关系。油气勘探实践表明,气烟囱往往与油气藏尤其是天然气水合物藏伴生,且油气及水合物多处于其上覆或两侧位置附近。通过大量油气及天然气水合物勘探实践、地质地球物理资料综合分析及油气地球化学分析等,充分证实了气烟囱与其上覆或两侧附近的油气及天然气水合物藏具有密切的成因联系。研究表明,气烟囱作为连接和沟通烃源/气源供给系统与油气藏及水合物藏之间的重要桥梁和纽带,是油气（水合物）勘探中判识追踪油气藏及水合物藏成因、确定其烃源/气源供给系统活动特征的重要依据和指示。因此,深入分析研究气烟囱系统成因及类型,不仅能够追踪探索和判识确定油气及水合物成因,阐明其运聚成藏规律及控制因素,而且能够指导油气及水合物勘探部署与综合评价工作。同时,通过油气及水合物成因的地球化学分析,亦可判识确定其气烟囱成因及其对油气和水合物运聚成藏的控制影响作用。     

海洋浅表层天然气水合物成藏特征

按照天然气水合物形成的气体疏导方式划分,渗漏系统是海洋浅表层天然气水合物藏形成的主要模式。关键成藏要素包括温压场、气源等,温压场主要控制天然气水合物成藏的平面分布和纵向分布;海底热流低值区有利于形成天然气水合物,但在海底热流超高的海域,只要有充足的气源供给,在高甲烷通量区深海浅表层也可以形成天然气水合物藏,而且往往与泥火山、气烟囱等特殊地质体伴生,形成致密的数米厚层状天然气水合物藏。浅表层天然气水合物藏气源主要是有机热解成因气,一般其深部均发育有成熟的含油气盆地,有烃源层广泛分布,并且干酪根发生过明确的生烃过程,形成的热解甲烷气通过断层、气烟囱等破碎带垂向运移通道渗漏上升,在温压场控制的相平衡区形成天然气水合物藏,因此,海底热流值较高的海盆也是浅表层天然气水合物藏形成的有利海域。     

New insights into the carbonate karstic fault system and reservoir formation in the Southern Tahe area of the Tarim Basin

As worldwide hydrocarbon exploration has extended from shallowly to deeply buried strata, reservoir quality has attracted substantial and persistent interest in petroleum geology. In particular, deeply buried strata (>5500 m) in the Tarim Basin have attracted considerable attention because carbonate reservoirs that have experienced fracture or dissolution have also been shown to demonstrate considerable hydrocarbon potential. Therefore, it is necessary to determine how these reservoirs are developed and distributed in detail from both scientific and practical standpoints.In this paper, we address this issue using a case study in the southern Tahe area, which is contained within the largest Palaeozoic marine oilfield in China. In the northern Tahe area, mega-paleokarst systems developed in the Ordovician strata; however, the reservoir quality in the southern part of the Tahe area is relatively poor because it is covered by insoluble formations during karstification. Observations of cores and analyses of images of well logging demonstrate that these reservoirs are dominated by caves, vugs and fractures that have developed near faults. We speculate that the faults penetrating insoluble formations represent the main dissolution passages that originally developed these karstic fault systems. Additionally, we analyse a series of outcrops, seismic data, and structures to characterize the spatial geometry of these major faults and their surrounding fractures in detail. Most of these are strike-slip faults, and their subsequent reservoirs can be divided into three categories based on their development, including dendritic, sandwich and slab reservoirs. Recent studies demonstrate that karstic fault reservoirs are most common traps in the study area. Although various types of carbonate karstic fault reservoirs are represented in this region, the dendritic karstic fault reservoir is the most hydrocarbon-rich.Guided by these initial results, 108 wells were drilled from 2013 to 2014, producing 485 thousand tons of oil and yielding success ratios greater than 89%. The average production of dendritic reservoirs is 37.4 tons per day (t/d), while those of sandwich and slab types are 20.2 t/d and 14.0 t/d, respectively. These results represent significant references for future hydrocarbon exploration and the development of similar deeply buried karstic fault reservoirs in the Tarim Basin and elsewhere.     

辽东湾地区Z油田常规砂岩油藏流体分布控制因素

流体分布控制因素是油气勘探开发的重要研究方向。辽东湾海域Z油田沙河街组为典型的常规砂岩层状构造油藏,流体分布复杂。为进一步明确流体分布差异的控制因素,利用油田多年开发的动静态资料,系统梳理流体垂向及平面发育特征,总结沉积和构造双因素对流体分布的控制作用。研究结果表明：Z油田垂向流体分布可划分为连续集中型和多段分散型;平面流体分布主要表现为连片型、分散型、分块型和局部倒置型。平面流体的分布主要受控于砂体平面展布形态和连通性,断层封堵性和断裂组合方式,以及局部复杂化的构造形态;砂体间发育的隔层控制着垂向流体分布。沉积和构造因素的双重影响,加剧了研究区平面及垂向流体分布的差异性,呈现出多流体系统的流体分布特征。系统总结流体分布主控因素,对油田后续高效开发具有较好的指导意义。