首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 406 毫秒
1.
The diagenetic environment, diagenetic responses, diagenetic transformation model and formation mechanisms of high-quality reservoirs (beach-bar sandstones of the Paleogene fourth member) in the Dongying depression were studied through the analysis of fluid inclusions, thin section and burial evolution history. The diagenetic fluids of the beach-bar sandstone reservoirs evolved from early high salinity and weak alkalinity to low salinity and strong acidity, late high salinity and strong alkalinity and late low salinity and acidity, which were accompanied by two stages of oil and gas filling. The fluids at the margins of the sandbodies were continuously highly saline and strongly alkaline. The western (eastern) reservoirs experienced early open (closed), middle open, and late closed diagenetic environments during their burial history. The flow pattern was characterized by upwelling during the majority of the diagenesis (in the east, a non-circulating pattern transitioned into an upwelling current). Due to the evolution of the diagenetic fluids, the diagenetic sequence of the beach-bar reservoirs was as follows: early weak carbonate cementation; feldspar and carbonate cement dissolution and authigenic quartz cementation; late carbonate and anhydrite cementation, authigenic feldspar cementation, and late quartz dissolution; and late carbonate cementation, feldspar dissolution, and authigenic quartz cementation. The diagenetic strength during these stages varied or was absent altogether in different parts of the reservoirs. Due to the closeness of the diagenetic environment and the flow pattern of the diagenetic fluids, the diagenetic products are variably distributed in the sandstones interbedded with mudstones and in the fault blocks. The evolution of multiple alternating alkaline and acidic diagenetic environments controlled the distribution patterns of the reservoir diagenesis and reservoir space, and the reservoir quality index, RQI, increased gradually from the margins to the centers of the sandstones. The closeness of the diagenetic environment and the flow patterns of the diagenetic fluids controlled the differences in the reservoir properties among the fault blocks. With increasing distance from the oil-source faults, the RQI values in the west gradually decreased and in the east initially increased and then decreased.  相似文献   

2.
延长油区上三叠统长 2地层河流相-三角洲相砂岩储层的物性明显受埋藏-成岩作用事件的影响。埋藏压实作用是导致砂岩孔隙丧失的主要原因,造成的平均孔隙度丧失为 17.8%。其中黑云母的早期成岩蚀变是造成原生孔隙丧失的一个重要原因。胶结作用造成的平均孔隙度丧失为 7.1%。其中碳酸盐胶结物和次生石英加大是造成砂岩物性降低的主要胶结物。碎屑颗粒周围绿泥石薄膜的存在阻止了一部分石英次生加大及碳酸盐胶结物的沉淀,使一部分原生粒间孔隙得以保存。晚期成岩阶段有机质分解形成的酸性流体及表生成岩作用阶段的大气降水是形成次生孔隙的主要原因,从而使长 2砂岩的物性得到改善  相似文献   

3.
朱芳冰  周红 《地球科学》2022,47(12):4724-4730
碳酸盐胶结物中氧碳同位素组成研究是分析成岩过程中流体-岩石相互作用的重要技术方法.综合运用岩石学、矿物学和地球化学方法，对辽河盆地西部凹陷沙河街组砂岩中碳酸盐胶结物的化学组成和碳酸盐胶结物及成岩流体同位素组成特征进行系统分析.研究表明，研究区碳酸盐岩主要为方解石和白云石，胶结物主要类型为嵌晶式胶结、孔隙式胶结、斑块状胶结和星点状胶结.碳、氧稳定同位素组成能有效地反映成岩-成矿流体及其他物质的来源，碳酸盐胶结物与现今浅层地下水氧同位素组成差异巨大而与变质水同位素组成具有相似性，反映了盆地演化过程中活动热流体对成岩作用的影响.包裹体的氢、氧同位素组成可表征成矿溶液的演化特征，砂岩碳酸盐胶结物包裹体更富集氢的轻同位素和氧的重同位素，表明发生了明显的“氧-18漂移”.碳酸盐胶结的成矿溶液表现出“受热雨水”的同位素组成特征，反映了深源活动热流体对成岩作用的影响.   相似文献   

4.
The Middle Jurassic Khatatba Formation acts as a hydrocarbon reservoir in the subsurface in the Western Desert, Egypt. This study, which is based on core samples from two exploration boreholes, describes the lithological and diagenetic characteristics of the Khatatba Formation sandstones. The sandstones are fine‐ to coarse‐grained, moderately to well‐sorted quartz arenites, deposited in fluvial channels and in a shallow‐marine setting. Diagenetic components include mechanical and chemical compaction, cementation (calcite, clay minerals, quartz overgrowths, and a minor amount of pyrite), and dissolution of calcite cements and feldspar grains. The widespread occurrence of an early calcite cement suggests that the Khatatba sandstones lost a significant amount of primary porosity at an early stage of its diagenetic history. In addition to calcite, several different cements including kaolinite and syntaxial quartz overgrowth occur as pore‐filling and pore‐lining cements. Kaolinite (largely vermicular) fills pore spaces and causes reduction in the permeability of the reservoir. Based on framework grain–cement relationships, precipitation of the early calcite cement was either accompanied by or followed the development of part of the pore‐lining and pore‐filling cements. Secondary porosity development occurred due to partial to complete dissolution of early calcite cements and feldspar. Late kaolinite clay cement occurs due to dissolved feldspar and has an impact on the reservoir quality of the Khatatba sandstones. Open hydraulic fractures also generated significant secondary porosity in sandstone reservoirs, where both fractures and dissolution took place in multiple phases during late diagenetic stages. The diagenesis and sedimentary facies help control the reservoir quality of the Khatatba sandstones. Fluvial channel sandstones have the highest porosities and permeabilities, in part because of calcite cementation, which inhibited authigenic clays or was later dissolved, creating intergranular secondary porosity. Fluvial crevasse‐splay and marine sandstones have the lowest reservoir quality because of an abundance of depositional kaolinite matrix and pervasive, shallow‐burial calcite and quartz overgrowth cements, respectively. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

5.
鄂尔多斯盆地彬长地区长6油层组发育与深湖相泥岩相伴生的细粒砂岩沉积,是致密油勘探的有利区域。根据岩心观察、铸体薄片鉴定及各类分析测试资料,研究彬长地区长6油层组砂岩储层的孔隙类型及物性特征、成岩演化过程,建立成岩相分类方案,并通过成岩相带平面展布指出勘探有利区。结果表明,研究区长6储层成岩阶段主要处于晚成岩A-B期,压实作用造成原始孔隙大量损失,后期高岭石胶结作用使得渗透率进一步降低。早期绿泥石薄膜的发育可以使原生孔隙得到保存;后期长石、岩屑等不稳定组分发生的溶蚀作用,使孔隙再次分配,物性得到提高。根据成岩作用对物性的影响,划分出强压实成岩相、强溶蚀成岩相、弱溶蚀成岩相、强钙质胶结成岩相,以及微裂缝成岩相等5种成岩相带。优质储层与成岩相密切相关,强溶蚀成岩相的砂体物性、含油性最好,是研究区长6储集层油气最为富集的成岩相带。  相似文献   

6.
沉积微相是影响陆相致密油气储层发育的重要控制因素,不同微相的成岩响应和储层质量不同,制约了储层精细刻画与有利区预测工作。通过岩心、薄片、测井、孔渗、扫描电镜、XRD矿物分析、微米CT和压汞资料,识别了鄂尔多斯盆地西南部延长组三角洲—湖相致密储层8种沉积微相类型,刻画了不同微相在矿物组成、成岩作用、储层物性和孔隙结构方面的差异。结果表明,不同微相储层的压实作用,溶蚀作用和自生绿泥石、伊利石的胶结作用差异明显。水下分流间湾、浅湖泥和半深湖泥储层中黏土和云母等塑性矿物组分含量高,受机械和化学压实影响更大。受大气水渗滤作用和生烃作用影响,水下分流河道,河口坝和席状砂储层中溶蚀孔较为发育。频繁的砂泥互层和湖流侵入导致滩砂体铁方解石胶结大量发育。自生绿泥石和伊利石胶结物的产状具有明显的沉积微相分带性,但不同微相储层的高岭石和硅质胶结差异不大。最后建立了致密储层孔隙连通性系数E和孔隙结构评价系数A,甄别了不同微相储层质量差异,可为储层精细刻画与分级评价提供指导。  相似文献   

7.
塔里木盆地满加尔凹陷志留系砂岩为无障壁的潮坪、滨岸及辫状河三角洲沉积的岩屑砂岩和岩屑质石英砂岩,对满北和满东、满南地区志留系砂岩成岩作用序次尤其是碳酸盐胶结的时间、方式和特征、物性的对比研究认为:砂岩中碳酸盐胶结的时间早晚对砂岩孔隙演化具有重要影响,满北地区志留系砂岩发育有大量早期泥晶碳酸盐胶结,显微镜下研究表明这种胶结作用发生在岩石受到充分压实之前,呈基底式胶结,岩石颗粒呈点接触或漂浮状分布于早期碳酸盐胶结物之中,这种胶结作用抑制了岩石后期的压实作用。尽管目前其埋藏达5 000～6 500 m,但其经历的压实作用并不强烈,粒间发育大量早期的碳酸盐胶结物,后来这些胶结物被溶蚀,形成了大量次生孔隙。而在满东和满南地区的志留系砂岩,碳酸盐胶结发生在岩石经过充分压实之后,晚期的碳酸盐胶结物仅分布于岩石经充分压实后的粒间孔隙中,含量较前者低,后期可供溶蚀的碳酸盐比前者少,因而溶蚀形成的次生孔隙有限。因此,尽管满东满南地区志留系埋藏比满北浅（3 700～5 000 m）,碳酸盐胶结物含量也低,也发育晚期碳酸盐胶结物的溶蚀,但岩石的压实作用比满北强,物性比满北低差。这主要与碳酸盐胶结的早晚有关,早期碳酸盐胶结对孔隙演化具有明显控制作用,有利于岩石孔隙的保存,为后来的溶蚀形成次生孔隙提供了条件。  相似文献   

8.
本文借助于薄片分析、扫描电镜分析、阴极发光分析和物性分析等研究手段,以鄂尔多斯盆地华庆地区长6油层组低渗透砂岩的形成机制为解剖对象,通过对砂岩埋藏前组成、化学成岩作用和物理成岩作用的相对重要性、自生矿物组成、孔隙构成、物性与孔隙结构等研究,明确了主要成岩作用对储层的影响。在此基础上,结合沉积相的研究,选择骨架颗粒构成、自生矿物组成、物性、孔隙构成以及粒间体积等有关的15个成岩相定量评价参数,对华庆地区长6油层组低渗透砂岩进行成岩相的定量评价。结果表明：① 华庆地区长6油层组砂岩经历了较强的物理成岩作用和较弱的化学成岩作用,原生孔隙是主要储集空间,压实作用是孔隙度降低的最主要因素,其次为方解石的胶结作用;② 成岩相定量评价表明,弱胶结、强压实成岩相以及强方解石胶结、中-强压实成岩相的储层质量均较差,受北部物源区控制的绿泥石胶结、弱-中等压实成岩相具有较好的储层质量,建议作为今后的优选勘探开发区。  相似文献   

9.
鄂尔多斯盆地A油田长2储层岩性主要为细粒长石砂岩。储层类型为低孔低渗型,平均孔隙度为12.6%,平均渗透率为10.7×10-3μm2。长2储层物性主要受沉积微相、成岩作用、裂缝发育程度与规模控制:辫状河河道砂坝中-细砂岩具有较高的孔隙度和渗透率,天然堤粉细砂岩和细砂岩的孔隙度和渗透率较低;压实作用是导致长2储层砂岩孔隙度降低的主要原因;胶结作用进一步破坏孔隙度,碳酸盐岩是砂岩孔隙度降低的主要胶结物;溶解作用一定程度上改善了长2储层物性,裂缝对砂岩渗透率的提高有重要贡献。  相似文献   

10.
Much effort has been expended in recent years on determining the factors influencing calcite cementation of sandstones, partly out of academic curiosity and partly because of the important influence these cements have on production from hydrocarbon reservoirs. Calcite cementation may occur pervasively throughout a sandstone sequence or be concentrated in certain horizons within which growth may be as concretions. We are only now beginning to understand the factors governing the growth and distribution of carbonate concretions in sandstones.  相似文献   

11.
利用流体包裹体的分析测试技术与研究方法,对鄂尔多斯盆地中西部长8油层组的成藏期次进行了研究。烃类包裹
体及其伴生的盐水包裹体的岩相学特征、均一温度、盐度、密度及成分分析显示,长8储层主要发育两期烃类包裹体,第
一期分布在早期方解石胶结物、石英颗粒表面及其连生的石英加大边中以及未切穿石英颗粒的早期愈合裂缝中,其伴生盐
水包裹体的均一温度峰值为80~90℃;第二期烃类包裹体分布在石英颗粒表面和切穿石英颗粒的裂缝中,其伴生盐水包裹
体的均一温度峰值为100~120℃。储层成岩作用与油气充注微观分析、成岩-烃类充注演化时间序列研究,结合地层埋藏史
和热史分析表明,研究区经历了三期烃类充注事件：第一期（约169~161 Ma） 充注规模小,砂岩中未捕获到这一期适合进
行均一温度与成分测定的烃类包裹体,因此本研究缺乏这期包裹体的温度与成分数据;第二期（约148~135 Ma） 烃类充注
对应前述获得均一温度与成分数据的第一期烃类包裹体;第三期烃类充注规模最大,发生在早白垩世晚期的125.2~105.7 Ma
之间,为主成藏期,对应前述获得均一温度与成分数据的第二期烃类包裹体。  相似文献   

12.
Fluid/rock interaction occurs frequently in the sandstones near the overpressure top in central Junggar Basin, and carbonate cementation-dissolution is related closely to the formation of secondary pores in the reservoir sandstones. From petrological, hydrochemical and fluid-inclusion studies of the deep-seated sandstones near the overpressure top in central Junggar Basin and the carbon and oxygen isotopic characteristics of carbonate cements in those sandstones, the following conclusions can be drawn: (1) Carbonates are the major cements. Two-stage cemen-tation was commonly developed, with late-stage ferroan carbonate cementation being dominant; several secondary porosity zones were developed vertically in the sandstones near the overpressure top, and there is a mutually com-pensatory relationship between the carbonate contents and the mean porosity; (2) the alkalescent formation-water chemical environments are in favor of carbonate precipitation; (3) there were two phases of thermal fluid activity which are related to the late-stage carbonate cementation-dissolution; (4) with the overpressure top as the boundary, carbonate cements in the sandstones have slightly negative δ13C and δ180 values, showing such a variation trend that the δ13C and δ18O values near the coal-bearing Jurassic strata are lighter, those in the overpressure top are heavier, and those at the upper part of the overpressure top are lighter, which is considered to be the result of kinetic isotope fractionation driven by episodically overpressured fluid flow; (5) carbonate cementation is closely associated with the decarboxylation of organic acids, and secondary porosity zones resultant from dissolution by organic acids and CO2 derived from Jurassic coal-beating strata, are the most important reservoir space of hydrocarbon, Studies of the mechanisms of carbonate cementation-dissolution and formation of secondary pores in the deep-seated sandstones near the overpressure top are of great significance both in theory and in practice in further investigating the rules of overpressured fluid flow (especially oil/gas migration) and predicting the reservoir space of hydrocarbon.  相似文献   

13.
准噶尔盆地腹部深层超压顶面附近(现今埋深4400~6200m, 温度105~145℃) 砂岩中广泛出现的碳酸盐胶结作用和次生溶蚀孔隙与超压流体活动关系密切.由于超压封闭和释放引起其顶面附近砂岩中的孔隙压力和水化学环境的周期性变化可导致碳酸盐沉淀和易溶矿物溶解过程交替出现.根据腹部地区超压顶面附近深埋砂岩成岩作用、碳酸盐胶结物含量、储集物性、碳酸盐胶结物碳、氧同位素和烃源岩热演化模拟等资料的综合研究表明: 含铁碳酸盐胶结物是主要的胶结成分, 长石类成分的次生溶蚀孔隙是主要的储集空间类型, 纵向上深层砂岩碳酸盐胶结物出现15%~30%含量的地层厚度范围约在邻近超压顶面之下100m至之上大于450m, 碳酸盐胶结物出现大于25%含量高值带分布在靠近超压顶面向上的250~300m的地层厚度范围, 超压顶面附近砂岩中碳酸盐胶结物含量高值的深度范围也是次生溶蚀孔隙(孔隙度10%~20%) 发育带的范围; 因晚白垩世以来深部侏罗纪煤系有机质生烃增压作用, 导致在超压顶面附近砂岩晚成岩作用阶段深部富含碳酸盐的超压流体频繁活动, 所形成的碳酸盐胶结物受到了明显的与深部生烃增压有关的超压热流体和有机脱羧作用的影响; 超压流体多次通过超压顶面排放, 使得超压顶面附近砂岩遭受了多期酸性流体溶蚀作用过程, 形成了次生溶蚀孔隙发育带.   相似文献   

14.
The sandstones of the Dhosa Sandstone Member of Late Callovian and Early Oxfordian age exposed at Ler have been analyzed for their petrofacies, provenance, tectonic setting and diagenetic history. These sandstones are fine to medium grained and poorly- to well sorted. The constituent mineral grains are subangular to subrounded. These sandstones were derived from a mixed provenance including granites, granite–gneisses, low- and high-grade metamorphic and some basic rocks of the Aravalli Range and Nagarparkar Massif. The petrofacies analysis reveals that these sandstones belong to the continental block-, recycled orogen- and rifted continental margin tectonic regime.The imprints of early and deep burial diagenesis of these sandstones include different stages of compaction, cementation, change in crystal boundaries, cement–cement boundaries, chertification and neomorphism. The sequence of cementation includes precipitation of calcite and its subsequent replacement by Fe calcite and silica cements. The typical intermediate burial (2–3 km depth) diagenetic signatures of these sandstones are reflected in the formation of suture and straight-line boundaries, and triple junctions with straight-line boundaries. The depositional environment, relatively low-energy environment that was below storm wave base but subjected to gentle currents, of the Dhosa Sandstone Member controlled the early diagenesis, which in turn influenced the burial diagenesis of these sandstones.  相似文献   

15.
Gas-bearing deposits in the Lower Mingyuefeng Formation of Paleogene, Lishui Sag, East China Sea Shelf Basin consist of shoreface sandstones of the highstand systems tract (HST) and transgressive systems tract (TST), and deltaic sandstones of the lowstand systems tract (LST) and falling stage systems tract (FSST). Detailed petrographic observations suggest that the diagenetic features and related evolution of these deposits cannot be simply characterized and demonstrated in the depth domain. However, the occurrence of diagenetic minerals systematically depends on the studied interval within the HST, TST, LST, and FSST; therefore, diagenesis in this region can be better constrained when studied in the context of the depositional environments and sequence stratigraphic framework. The eogenetic processes in such settings include: (1) microcrystalline siderite precipitated as concretions in almost all environments and systems tracts, which inhibited further mechanical compaction; (2) grain dissolution and kaolinitization occurred in shoreface HST sandstones and deltaic LST and FSST sandstones; (3) glaucony was locally observed, which did not clearly reflect the controls of facies or sequence stratigraphy; and (4) cementation by pyrite aggregates occurred in the shoreface HST sandstones and deltaic LST sandstones. The mesogenetic diagenesis includes: (1) partial conversion of kaolinite into dickite in deltaic LST sandstones, and minor chlorite cementation in deltaic FSST sandstones; (2) transformation of kaolinite into illite and quartz cementation in deltaic LST and FSST sandstones; (3) frequent precipitation of ankerite and ferroan calcite in shoreface TST sandstones and early HST sandstones, forming baffles and barriers for fluid flow, with common calcite in shoreface HST sandstones as a late diagenetic cement; and (4) formation of dawsonite in the deltaic LST and FSST sandstones, which is interpreted to be a product of the invasion of a CO2-rich fluid, and acts as a good indicator of CO2-bearing reservoirs. This study has thus constructed a reliable conceptual model to describe the spatial and temporal distribution of diagenetic alterations. The results may provide an entirely new conceptual framework and methodology for successful gas exploration in the continental margins of offshore China, thus allowing us to predict and unravel the distribution and quality evolution of clastic reservoirs at a more detailed and reliable scale.  相似文献   

16.
延长组长8 油层组是鄂尔多斯盆地镇泾区块的主力油层之一,岩性以岩屑长石砂岩和长石岩屑砂岩为主,为典型的 特低孔特低渗储层。储集空间以次生溶蚀粒间孔为主,喉道以缩颈型、片状和弯片状为主,孔喉结构发育3 种类型,以II 型为主。长8 砂岩储层特征主要受沉积作用、成岩作用、裂缝发育程度和油气充注4 个因素控制。最有利于储层发育的沉积 微相为水下分流河道,且中砂岩的储集物性好于细砂岩,富含石英、长石和变质岩岩屑的砂岩的储集物性好于火成岩岩屑、 沉积岩岩屑和云母含量高的砂岩。成岩作用对储集物性的影响具有双重性,建设性成岩作用包括溶解和孔隙衬里绿泥石胶 结作用2 种,两者均很发育的层段是油气储集的最有利地带;破坏性成岩作用主要包括机械压实作用和晚期亮晶方解石胶 结作用。裂缝以白垩纪末- 古近纪的构造裂缝为主,其使长8 储层渗透率急剧增大,储层非均值性增强。油气充注对储集 物性的影响主要表现为促进溶解作用的发生以及次生孔隙的形成和保存。  相似文献   

17.
东濮凹陷桥口地区沙三段碎屑岩成岩作用与储层特征   总被引：5，自引：1，他引：5  
东濮凹陷桥口地区沙三段碎屑岩经历了复杂的成岩历史。砂岩的主要成岩事件有:机械压实、碳酸盐胶结、石英加大、黄铁矿生成、高岭石的形成和转化、绿泥石生成、伊利石沉淀、斜长石的钠长石化、石膏和重晶石的形成,以及沸石矿物的生成和次生孔隙的产生。混层蒙皂石-伊利石化随埋深增加而增强,相邻页岩的成岩演化是砂岩胶结物成分的最重要来源。砂岩的成岩作用主要受沉积相的控制,处于中成岩晚期阶段的沙三段砂岩可划分为四种成岩相:(1)碳酸盐胶结成岩相;(2)石英加大自生成岩相;(3)粘土蚀度成岩相;(4)不稳定碎屑溶蚀成岩相。四种成岩相组成了四种不同的储层类型,储层性质的对比分析对识别致密气层中的油气产层具有重要意义。  相似文献   

18.
The Shishugou Group, which consists of Middle Jurassic Toutunhe Formation and Upper Jurassic Qigu Formation, is currently an important hydrocarbon exploration target in the Fukang Sag of Junggar Basin, China. The Shishugou Group sandstones experienced a complex diagenetic history with deep burial (3600–5800 m) to develop low–ultralow porosity and permeability reservoir with some high-quality reservoirs found in the tight sandstones owing to the reservoir heterogeneity. This integrated petrographic and geochemical study aims to unravel the origin and alteration of calcite cement in the Shishugou Group sandstones and predict fluid–rock interaction and porosity evolution. The Shishugou Group sandstones (Q43.8F7.4R48.8) have a dominant calcite cement with strong heterogeneity forming in two generations: poikilotopic, pore-filling masses that formed at an early diagenetic stage and isolated rhombs or partial grain replacements that formed at a late stage. The Shishugou Group, which are lacustrine sediments formed in low–medium salinity lake water in a semiarid–arid climatic environment, provided the alkaline diagenetic environment needed for precipitation of chlorite and early calcite cements in early diagenesis. The Ca2+ of the pore-filling calcite cements was sourced from weathering or dissolution of volcanic clasts in the sediment source or during transport in under oxidising conditions. The δ18OV-PDB and δ13CV-PDB values of calcite were significantly controlled by distance from the top unconformity and underlying coal-bearing stratum with carbon sourced from atmospheric CO2, and organic matter. The early carbonate cement inhibited burial compaction producing intergranular pore spaces with enhanced reservoir properties by late dissolution under acidic conditions. Anhydrite cement reflects reaction of organic acid and hydrocarbon with the sandstones and is associated with fluid migration pathways. The fluid–rock interactions and porosity evolution of the tight deep sandstones produced secondary pores that filled with hydrocarbon charge that forms this deep high-quality reservoir.  相似文献   

19.
薄片鉴定、流体包裹体分析、埋藏演化史与有机质热演化史分析、膏岩层脱水及黏土矿物转化分析等研究表明：河西务构造带古近系沙河街组四段储集层经历了碱性→酸性→碱性→弱酸性→弱碱性的成岩环境演化过程;成岩作用演化序列为：压实作用→长石溶蚀和(或)石英加大→碳酸盐胶结和(或)硬石膏胶结→少量碳酸盐胶结物溶解→少量黄铁矿胶结。利用“反演回剥”的原理, 以铸体薄片资料为基础, 计算了各关键成岩作用对储集层面孔率的贡献量, 并利用面孔率-孔隙度的函数关系, 结合机械压实校正, 定量地恢复了不同成岩特征储集层的实际孔隙度演化史。根据孔隙度演化史与油气成藏史匹配关系, 河西务构造带沙四段储集层第1期油气成藏时期储集物性较好, 孔隙度高达20％左右。第2期油气成藏时期, 北部区块储集层碳酸盐胶结强烈, 孔隙度急剧降低至7％左右, 不利于油气充注补充;而南部区块储集层碳酸盐胶结作用弱, 孔隙度仍以大于10％为主, 有利于油气充注补充和成藏, 成为有利勘探目标。  相似文献   

20.
根据对岩石铸体薄片和阴极发光薄片、地层厚度、古地温梯度以及镜质体反射率等资料分析研究认为：塔中地区东河砂岩经历了压实作用、粘土胶结、石英次生加大、碳酸盐胶结、溶蚀作用、自生高岭石沉淀等多种成岩作用，目前已经达到了晚期成岩阶段。这些成岩作用在塔中4井以东和以西的地区存在较明显的差异，西部进入早成岩阶段B期和晚成岩阶段A期的时间较早，成岩演化程度较高，且具有下部溶蚀上部胶结的分带性；而东部则反之。优质储层主要分布于颗粒成分较纯、泥质含量较低、构造位置上长期处于高部位、被油气充注，但未被晚期碳酸盐胶结的地区。即二叠纪以来长期处于构造高部位的前滨-临滨相带内。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号