浅水台地相碳酸盐岩的生烃潜力

浅水台地相碳酸盐岩是中国海相碳酸盐者最主要的沉积类型,其沉积环境有利于生物的繁殖,而不利于有机质的保存。由于沉积界面附近多为氧化环境,所以有机质在其沉积和浅埋阶段被大量分解,丰度较低,类型变差。虽然有机质来源主要为低等水生生物,但生烃潜力,特别是液态烃生成潜力较低,因此浅水台地相碳酸盐岩一般不能作为重要的油源岩而主要作为气源岩。     

中国南方碳酸盐岩油气勘探远景分析

南方碳酸盐岩地层油气勘探工作,已历时数十年,对其勘探远景看法存在两种截然不同的认识:有的认为是能找到大油气田的“基地论”者,有的认为是能找到小油气田的“鸡肋论”者。作者归纳列举出它们立论石油地质学有利的依据6条,不利的依据5条,呈献于读者,以利于南方碳酸盐岩地层油气勘探的早日突破。     

鄂尔多斯碳酸盐岩去白云石化及其与储集性的关系

鄂尔多斯下奥陶统碳酸盐岩储层去白云石化主要有下列类型:与不整合面有关的去白云石化主要是大气淡水沿不整合面运移,使其附近的铁白云石发生差异去白云石化,产生大量溶蚀组构和少量去白云石化方解石,以低Sr,Fe,Mn,具低温包裹体等为特征;埋藏环境中去白云石化是与缝合线、石膏结核、埋藏溶蚀孔洞缝和构造裂隙有关的类型,主要与Mg²⁺的不断消耗、Ca²⁺含量增加,及有机质热成熟作用和油气的运移聚集有关,以富Mg,Fe,Mn,Sr,低δ¹⁸O,δ¹³C,包裹体均一温度高,可造成大量去白云石化方解石为特征。去白云石化白云岩孔隙度明显比其他类型白云岩和灰岩高,不仅可以提高储层的孔渗性,亦可使非渗透层变为高孔渗层。     

DIAGENETIC HISTORY OF LATE PALAEOCENE POTENTIAL CARBONATE RESERVOIR ROCKS, KOPET-DAGH BASIN, NE IRAN

The Upper Palaeocene (Thanetian) Chehel-Kaman Formation in the Kopet-Dagh Basin of NE Iran is principally composed of carbonates with minor siliciclastics and evaporites. Six stratigraphic sections were measured and more than 1,000 samples were collected for petrographic analysis, together with analyses of carbon and oxygen isotopes and trace element content. Four major carbonate lithofacies (and 13 subfacies) have been identified in previous studies and are interpretd in terms of deposition in a shallow-marine environment.
The petrographic analyses indicate that the Chehel-Kaman Formation carbonates have undergone a complex diagenetic history which includes compaction, cementation, micritization, dissolution, silicification, dolomitization, neomorphism and fracturing. δ¹⁸O and δ¹³C values in Chehel-Kaman Formation limestones range between +0.8 and -15.1%₀ PDB, and -2.82 and +3.5%₀ PDB, respectively. These variations are interpreted to reflect meteoric and burial diagenetic processes. Variations in trace-element concentrations (Fe and Mn increased while Na decreased) also indicated the effects of meteoric flushing. The limestones appear to have been formed at about 28°C.
Chehel-Kaman Formation dolomites were divided into d1 (finely-crystalline) and d2 (coarsely-crystalline) types. Petrographic and geochemical results indicated that the d1 dolomites formed under sabkha conditions from a parental solution at around 26°C, while d2 dolomites formed during burial diagenesis with much hotter pore fluids (around 72°C). The paragenetic sequence indicates that primary porosity decreased during early stages of diagenesis, although secondary porosity was subsequently created improving the reservoir quality of the carbonates.     

HYDROCARBON GENERATION HABITAT OF TWO CRETACEOUS CARBONATE SOURCE ROCKS IN SE TURKEY

A detailed petroleum geochemical study has been carried out on two Cretaceous carbonate source rock units, the Karababa Formation A Member and the Karabogaz Formation, in the Adiyaman area of SE Turkey. The purpose was to compare the hydrocarbon generation habitat of these two units which appear to be almost identical in terms of their bulk source rock characteristics. Thus, the TOC contents of the Karababa Formation A Member and the Karabogaz Formation are 0.24–3.79% and 0.50–5.86%, respectively. Hydrogen Indices are generally greater than 300 mg HC/ g TOC and both units have similar maturity levels. However, the results of pyrolysis-gas chromatographic analyses showed that the organic matter in the Karababa Formation A Member is richer in sulphur compounds, and the presence of sulphur-rich kerogen resulted in the early generation of hydrocarbons from this unit. Both the dominant activation energy and the frequency factor turned out to be lower for the Karababa Formation A Member. Consequently, oil generation in the Karababa Formation A Member proceeds more rapidly for a given temperature history than it does in the Karabogaz Formation. Moreover, the results of multi-step Py-GC analyses indicated that the composition of hydrocarbons generated in these two carbonate source rocks will be different, particularly during the early stages of maturation. Early-generated oil from the Karababa Formation A Member has the composition of a mature oil, whereas oil from the Karabogaz Formation reaches the same composition at a higher maturity.     

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塔里木盆地碳酸盐岩岩溶型储集层具有埋藏深、非均质性强的特点，利用某种单一技术很难对岩溶型储集层进行较为准确的预测。文章针对碳酸盐岩岩溶型储集层发育和分布的特点，对其在地震资料上的响应特征进行深入的分析；然后应用地震属性参数分析、古地貌恢复、应变量分析裂缝预测、井约束条件下的全三维波阻抗反演等技术方法进行预测分析，认为在地震属性上低相干、强振幅、振幅横向变化率较大、古地貌斜坡部位及古水系两侧、高应变量及裂缝密度较高的区域为碳酸盐岩岩溶发育区；最后利用以上属性参数进行多参数融合，对碳酸盐岩岩溶型储集层进行综合预测评价，划分出有利和较有利的岩溶发育区带，指导井位部署和储量计算等工作。通过多口井的实际钻探结果表明，储层预测评价结果是较为可靠的，并为井位部署和储量计算提供了可靠的地质依据。     

FAULT-RELATED SOLUTION CLEAVAGE IN EXPOSED CARBONATE RESERVOIR ROCKS IN THE SOUTHERN APENNINES, ITALY

The deformation associated with a number of kilometre-scale strike-slip fault zones which cut through outcropping carbonate rocks in the Southern Apennines was investigated at regional and outcrop scales. These faults trend roughly east-west and were studied at the Gargano Promontory on the Adriatic Coast (in the Apulian foreland) and in the Matese Mountains, about 120 km to the west (within the Apenninic fold-and-thrust belt). The fault zones are 200–300 m wide and typically comprise a core surrounded by a damage zone. Within fault cores, fault rocks (gouges and cataclasites) typically occur along master slip planes; in damage zones, secondary slip planes and solution cleavage are the most important planar discontinuities. The protolith carbonates surrounding the fault zone at Gargano show little deformation, but they are fractured in the Matese Mountains as a result of an earlier thrust phase.
Cleavage surfaces in the damage zone of the studied faults are interpreted to be fault-propagation structures. Our field data indicate that cleavage-fault intersection lines are parallel to the normals of fault slip-vectors. The angle between a fault plane and the associated cleavage was found to be fairly constant (c. 40") at different scales of observation. Finally, the spacing of the solution cleavage surfaces appeared in general to be regular (with a mean of about 22 mm), although it was found to decrease slightly near a fault plane. These results are intended to provide a basis for predicting the architecture of fault zones in buried carbonate reservoirs using seismic reflection and borehole data.     

碳酸盐岩中一种“潜在”的资源——油砂中碳酸盐胶结物烃

碳酸盐岩烃源岩的资源评价是油气领域的热点和难点问题,而总有机碳含量（TOC）又是一个非常重要的参数,通常在测定总有机碳含量时,对赋存于碳酸盐岩的烃都未加以计算。通过对鄂尔多斯盆地西峰油田三叠系延长组6个油砂样品中游离烃、封闭烃、碳酸盐胶结物烃、束缚烃和石英颗粒包裹体烃的分步分离和抽提,并用盐酸（10％）处理碳酸盐胶结物后,从酸液中萃取的碳酸盐胶结物烃（相当于氯仿B）的C₂₉甾烷20S/（20S+20R）和ββ/ （αα+ββ）比值明显小于其他赋存形式的烃,它可能是碳酸盐沉淀（胶结）时赋存于其中的“原生”烃。     

广西十万大山盆地早三叠世深水碳酸盐岩的沉积作用及油气潜力

油气聚集与沉积相带密切相关,随着油气勘探发展的需要,碳酸盐岩沉积相的研究,已由浅水环境转向深水环境。美国、墨西哥、中东和北海的深水碳酸盐岩中,已证实有丰富的石油和天然气资源。而碳酸盐岩重力流储层已成为油气勘探一个新的领域。墨西哥的波查里卡油田塔马布拉灰岩产出石油现已超过9亿桶就是最好例证。     

碳酸盐岩生烃指标及生烃量评价的新认识

我国存在大量平均有机碳丰度很低(一般小于0.20%)、但仍能达到以往提出的碳酸盐岩烃源岩有机碳丰度下限(一般在0.10%)的碳酸盐岩,多年的勘探未发现其能生成原生工业性油气藏,表明该下限提得过低,原因在于传统观点笼统地认为碳酸盐岩中有机质生烃能力较高、碳酸盐岩排烃率高、提出过高的高演化阶段碳酸盐岩原始有机碳恢复系数,并且未考虑运移散失。在重新考虑这些因素后,认为烃源岩平均有机碳下限指标应主要由实际情况的类比来确定。碳酸盐岩烃源岩、高—过成熟阶段的烃源岩以及气源岩的有机碳丰度下限未必分别明显低于泥岩烃源岩、成熟阶段的烃源岩和油源岩,它们的平均有机碳含量都应在0.40%~0.50%以上。     

SHALLOW-MARINE MICROPOROUS CARBONATE RESERVOIR ROCKS IN THE MIDDLE EAST: RELATIONSHIP WITH SEAWATER Mg/Ca RATIO AND EUSTATIC SEA LEVEL

The formation of shallow-marine microporous carbonate reservoir rocks remains poorly understood in spite of their economic importance, particularly in the Middle East. In this paper, we investigate relationships between the stratigraphic occurrence of these carbonates in the Middle East and (i) the evolution of the Mg/Ca ratio in seawater; and (ii) cyclic variations in relative sea-level.
An inventory of carbonate formations in the Middle East was compiled for three geological time intervals characterised by different seawater chemistries: the Late Carboniferous to Triassic (aragonite seas); the Cretaceous (calcite seas); and the Cenozoic (transitional from calcite to aragonite seas). For each time interval, carbonate formations described as microporous have been listed.
During the Cretaceous calcite sea, eleven microporous carbonate formations were deposited in the Middle East. However, no microporous carbonates were formed during the Late Carboniferous to Triassic, a time of aragonite seas. During the Cenozoic, four of the five microporous carbonate formations recorded were deposited before the transition from calcite to aragonite seas. Thus, these shallow-marine microporous carbonates appear to have developed from precursor muds which were mainly composed of low-Mg calcite crystals. Moreover, during the Cretaceous and the Cenozoic, microporous carbonate formations in the Middle East were generally associated with major transgressions and highstands of relative sea level.
The relatively high stability of low-Mg calcite muds may explain why shallow-marine microporous carbonates formed during time intervals with calcite seas. In contrast to muds composed of aragonite or high-Mg calcite crystals, the original microfabric (including intercrystalline microporosity) of low-Mg calcite muds can partly survive moderate diagenesis.     

中国陆表海碳酸盐岩有机质的生烃潜力

有机质类型指标中反映母质来源的指标并不能完全代表生烃能力的大小.目前积累的大量分析数据表明,许多地区沉积的贫有机质海相碳酸盐岩O/C原子比H/C原子比落在干酪根类型图上的Ⅲ型区域,同一套地层中碳酸盐岩干酪根H/C明显低于泥岩,碳酸盐岩干酪根镜检可发现无定形组微粒化、藻类体出现黑心结构、存在大量类似镜质组的显微组分,均表明其有机质生烃降解率很低(只相当于Ⅲ型干酪根),这是氧化的沉积环境对有机质改造的结果,符合有机相的分布规律.在研究其生烃数量与机制时,不宜采用有机碳丰度很高、原始降解率很高的低成熟泥灰岩的模拟实验结果.     

碳酸盐岩中的一种储集空间—微孔隙

塔里木盆地北部沙14井的下奥陶统低能碳酸盐岩中喷出高产油气流,其主要储集空间为微孔隙。这是我国首次发现的以微孔隙为主要储集空间的碳酸盐岩储层。微孔隙的特征如何?在成岩过程中是如何演化的?其成因和控制因素是什么?本文根据国内外最新资料,简要回答了这些问题。     

从桂林岩溶特征谈碳酸盐岩潜山储层研究

本文通过对桂林地区岩溶地貌考察和调研,提出了认识碳酸盐岩潜山储层的3个重点内容,即对砂岩产状的预测;潜山溶孔、裂缝发育与岩性、结构的关系;储集空间发育与构造的关系。     

华北下古生界碳酸盐岩储集性初步分析

华北地区下古生界主要为一套浅海台地碳酸盐岩。其中奥陶系中统及寒武系下统是该区储集岩发育的主要层段。储集岩以溶蚀孔隙和裂隙为主,加里东期和燕山-喜山期的岩溶作用及断裂作用是储集岩形成的主要地质因素。     

RESERVOIR POTENTIAL OF A LACUSTRINE MIXED CARBONATE / SILICICLASTIC GAS RESERVOIR: THE LOWER TRIASSIC ROGENSTEIN IN THE NETHERLANDS

The Lower Triassic Rogenstein Member of the Buntsandstein Formation produces gas at the De Wijk and Wanneperveen fields, NE Netherlands and consists mainly of claystones with intercalated oolitic limestone beds. The excellent reservoir properties of the oolites (φ= 20‐30%; k = 5‐4000 mD) are predominantly controlled by depositional facies. Oolitic limestones are interpreted as the storm and wave deposits of a shallow, desert lake located in the Central European Buntsandstein Basin. The vertical sequence of lithofacies in the Rogenstein Member indicates cyclic changes of relative lake level. The reservoir rock is vertically arranged in a three‐fold hierarchy of cycles, recognised both in cores and wireline logs. These cycles are a key to understanding the distribution of reservoir facies, and are used as the basis for a high‐resolution sequence stratigraphic correlation of the reservoir units. Slight regional‐scale thickness variations of the Rogenstein Member (in the order of tens of metres) are interpreted as the effects of differential subsidence associated with the inherited Palaeozoic structural framework. The depositional basin can be subdivided into subtle palaeo‐highs and ‐lows which controlled facies distribution during Rogenstein deposition. Oolitic limestones show their greatest lateral extent and thickest development in the Middle Rogenstein during large‐scale maximum flooding. Potential reservoir rocks (decimetre to metres thick) are present in the NE Netherlands, in particular in the Lauwerszee Trough and the Lower Saxony Basin, where abundant gas shows of 200 ‐ 4000 ppm CH₄ have been recorded. Preserved primary porosity is interpreted to be a result of rapid burial in subtle depositional palaeo‐lows in this area. The thickest, amalgamated oolite intervals (tens of metres thick) occur in the eastern part of the Central Netherlands Basin. Because of poor reservoir properties, other areas appear to be less promising in terms of Rogenstein exploration potential.     

塔东上元古界—下古生界碳酸盐岩天然气藏预测

塔里木盆地东部具有古隆起、中拗陷、晚稳定的构造发育特征,震旦—寒武系碳酸盐岩生储盖组合好、烃源岩有机质丰度高、热演化程度高、构造和地层圈闭大、形成早、埋藏较浅,具备了形成大型天然气干气藏的地质条件,预测塔东是未来的大气区。     

千米桥潜山碳酸盐岩凝析气藏储层评价方法

千米桥潜山凝析气藏的发现是20世纪末在渤海湾盆地的重大发现。千米桥潜山凝析气藏储层岩性为碳酸盐岩。由于储集空间类型既有基质孔隙型又有裂缝和溶蚀孔隙型,储层的定量评价难度很大。随着成像测井技术(尤其是微电阻率成像测井FMI技术)的研制成功,已经可以对近井壁地质现象进行直观、定量的评价;但受探测深度的限制,该技术不能对距离井壁较远储层的储集类型和储集性能的变化做出有效预测。以对千米桥潜山储层的成功评价为实例,介绍了在系统取心刻度测井的基础上采用将3700常规测井资料与成像测井资料相结合的对岩性进行识别的方法,和将有效孔隙分为(与宏观岩心观察和微观分析化验资料相吻合的)基质孔隙、裂缝孔隙和溶洞孔隙的对储集类型和储集性能进行定量评价的方法。同时还介绍了应用CMR核磁共振测井技术定性判别流体性质的方法。     

任丘古潜山油田碳酸盐岩储层研究

前言任丘潜山带高产油气藏由四个走向北东的古潜山高点组成,自北而南呈雁行式斜列,其西侧被大断层切割,坡度较陡,东坡较缓。据钻探揭示,有两大套沉积建造,上为新生界第三系陆相碎屑岩沉积,厚约3000米;下为古生界和震旦亚界海相碳酸盐岩为主的沉积,厚3000余米。     

川东某潜高构造碳酸盐岩储层含流体性质判别方法研究

川东地区某潜高构造嘉陵江组储层为碳酸盐岩储层,其地质特征和流体分布状态具有复杂性和多变性,测井解释采用常规方法(如利用含油气饱和度或地层电阻率的变化特征)来判断流体性质往往不够准确。为了提高对流体性质的识别精度,提出了一种模糊灰关联模式识别的方法。将灰关联分析技术与模糊集理论结合起来,采用模糊相对隶属度概念对判别对象序列作标准化处理并在此基础上求取模糊灰关联度向量,然后根据最大隶属原则判别流体类型归属。将该技术用于高峰场地区储层流体性质判别与试油结果对比后发现,该技术判别结论合理,识别精度高,有一定的地质效果。