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库车坳陷白垩系深层致密砂岩储层溶蚀作用实验模拟研究 总被引：1，自引：1，他引：0
库车坳陷前陆区白垩系发育特低物性、强非均质性和高稳产砂岩储层,溶蚀作用显著,但成因机制尚不是很明确。利用高温高压热模拟实验还原了目的层在成岩演化过程中1种表生流体和2种埋藏流体环境下溶蚀作用差异,揭示了成岩矿物演化过程及储集空间结构变化特征。结果表明,表生成岩期大气淡水淋滤弱酸性流体环境（CO2饱和溶液,pCO2=1 MPa）溶蚀作用最为显著,长石类矿物发生明显溶蚀,石英和黏土矿物相对难溶,Na+、Ca2+和K+等离子析出明显,Si4+和Al3+析出较少,样品表面沉淀出较多的疑似多边形石英和铝硅酸类矿物;成岩晚期油气充注酸性流体环境（乙酸溶液,2 mL/L）溶蚀作用其次,易于溶解白云石、石膏和长石类矿物,Ca2+、Mg2+、Na+和Si4+等离子析出明显,样品表面无沉淀;成岩早-中期碱性流体环境（NaHCO3溶液,pH=7.46、HCO3-=0.6 mol/L）溶蚀作用相对较弱,石英、长石和部分黏土矿物均发生了不同程度的溶蚀,且随着温度、压力的增加,溶蚀作用程度增加。综合分析表明:表生流体是研究区砂岩储层溶蚀孔隙发育的关键因素,其次为有机酸和碱性埋藏流体。这一认识能够丰富致密砂岩储层孔隙成岩演化理论,为下一步寻找规模储层发育区和气田有效开发提供理论支撑。 相似文献
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博兴洼陷东南部沙四段储层的流体史研究 总被引：3，自引：0，他引：3
通过成岩矿物的世代关系、流体包襄体研究和荧光检测，重现了研究区沙四段深部(2700m～3000m)和浅部(1600m～2700m)流体活动和油气充注历史。流体充注过程为：晚成岩阶段早期富含有机质的酸性流体形成和运移，碳酸盐矿物溶解和次生孔隙形成→东营末期第一期石油运移→第一期盐水流体运移和石英沉淀结晶→馆陶期—明化镇期开始第二期石油运移→第二期盐水流体运移和新的石英结晶。浅部储层中缺少第一期石油充注和第二期盐水流体充注。盐水流体可能与油田底水或边水相当。富含有机的酸性流体与岩石作用时，矿物的溶蚀有利于次生孔隙的形成。 相似文献
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《地质科技情报》2021,40(1)
成岩流体酸碱性对砂岩次生孔隙的形成具有重要影响。从酸性和碱性成岩流体演化角度分析鄂尔多斯盆地上古生界致密砂岩成岩流体酸碱性对物性的控制作用。依据大量铸体薄片观察、扫描电镜、X衍射分析、常规物性测试和高压压汞,详细研究了鄂尔多斯盆地东缘临兴和神府地区上古生界致密砂岩的岩石矿物学特征、物性特征、成岩作用、孔隙成因类型和孔喉结构特征,探讨了致密砂岩储层酸性和碱性成岩流体环境的识别、分带、分布和发育的各类伴生孔隙,并分析了成岩流体环境的演化过程及物性响应特征。在埋藏过程中,工区上组合层系经历了碱性-酸性-碱性的成岩流体演变模式,下组合含煤层系经历了酸性-碱性的成岩流体演变模式。酸性成岩环境以长石溶蚀、石英加大和自生高岭石沉淀为主要特征,发育长石溶蚀孔、黏土矿物晶间孔等孔隙类型,孔喉半径较大,储层质量相对较好;碱性成岩环境以石英溶蚀、自生绿泥石沉淀为主要特征,以石英溶蚀孔、黏土矿物晶间孔为主要孔隙类型,孔喉半径较小,储层质量相对较差。酸碱过渡带致密砂岩储层介于两者之间。但是每类储层的物性和孔喉结构变化较大。成岩流体环境在纵向上呈现分带特征,自上而下发育碱性带、酸碱过渡带、酸性带、酸碱过渡带和碱性带,不同地区之间分带深度边界有差别;在酸碱过渡带中,局部地区发育酸性带、较弱酸性带和较弱碱性带。 相似文献
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为研究克拉美丽气田滴西地区石炭系巴塔玛依内山组火山岩储集层的流体演化过程,对储集层裂缝中的石英、方解石、黄铁矿等自生矿物进行了电子探针、流体包裹体及同位素分析研究。结果表明,SiO2主要来自深部热液流体,CO2来源具有深部热液、烃类流体混合改造的特征。在压力梯度与浮力驱使下,富含SO2等挥发分的含硅热液沿断层向上及两侧运移,分别形成具拱张-高温特征以及具隐爆-低温特征的石英脉。伴随深部流体由酸性向弱碱性的演化、压力的降低、CO2含量和盐度降低、温度变化,在收缩缝中沉淀出早期方解石。在岩体顶部长期暴露出地表地质背景下,当大气淡水与偏碱性盆地流体相遇时,在风化缝中形成保留渗流环境特征的方解石胶结物。埋藏期构造作用形成构造裂缝,烃类的充注-漏失使孔隙流体再次由酸性变为碱性,并在溶蚀孔缝中沉淀出晚期亮晶方解石。晚期热液作用的叠加形成磷灰石、方解石及黄铁矿矿物组合。石英、方解石等的充填作用使裂缝由开启变为闭合,对储层物性主要起破坏作用。 相似文献
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受震旦纪末期桐湾运动影响,四川盆地震旦系灯影组白云岩因遭受大气降水岩溶作用而发育了丰富的溶蚀孔隙。虽然经历了漫长的埋藏成岩演化过程,深层灯影组白云岩中仍见有丰富的储集空间未被成岩矿物充填而保存下来。通过对钻井及野外剖面进行系统岩石矿物学研究发现,储集空间保存段是灯影组上部的沥青显示段;而没有沥青的下部白云岩中的孔隙空间多被白云石等成岩矿物所充填。对林1井研究发现,上部沥青发育段白云岩储层孔隙度多大于3.0%,最高可达10.6%,平均为4.0%;但下部沥青不发育的自生白云石充填段孔隙度一般都小于3.0%,平均为1.95%。下部白云岩段溶蚀孔洞中自孔洞边缘向中心,所充填的白云石中流体包裹体均一温度从120℃逐渐增加至238℃;电子探针分析Fe、Mn平均含量从0.063%和0.025%逐渐升高至0.35%和0.108%;氧同位素组成δ18 OVPDB从-6.8‰逐渐降低至-11.2‰;表明了下部沥青未充填段成岩充填作用在埋藏过程中持续进行。油气充注改变了白云岩储层中的成岩流体环境并抑制了成岩矿物的形成;在后期埋藏过程,油逐渐转变成沥青覆盖在孔洞壁周围,也抑制了成岩矿物的沉淀形成;因而在现今沥青存在的深层白云岩储层中仍有丰富的孔隙空间保存下来。 相似文献
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惠州凹陷东部珠海组储层碱性成岩作用及孔隙演化 总被引：1，自引：0，他引：1
根据铸体薄片、扫描电镜、粒度分析、X衍射等资料，对惠州凹陷东部珠海组储层的岩石学特征、成岩作用和孔隙演化过程进行分析研究。研究认为，惠州凹陷东部珠海组储层的岩石类型以岩屑砂岩、长石质岩屑砂岩、岩屑质石英砂岩和岩屑质长石砂岩为主，结构成熟度与成分成熟度较低。砂岩埋藏过程中经历了明显的碱性成岩作用:石英的溶蚀与交代、碳酸盐矿物胶结、伊利石和绿泥石的沉淀以及钠长石化等。碱性成岩作用对孔隙的影响包括:石英溶蚀形成次生溶孔、碳酸盐胶结物沉淀损失粒间孔隙、黏土矿物沉淀形成晶间微孔。研究区珠海组主要发育粒内溶孔和粒间溶孔，原生孔隙较少。储层现今处于中成岩阶段A期，早期经历了强烈的压实作用，使其孔隙度由原始孔隙度32.1%降低至8.8%。早成岩阶段为碱性成岩环境，石英溶蚀增孔约0.5%；碳酸盐、硫酸盐、伊利石等胶结物沉淀减孔约2.3%。中成岩阶段A期为酸性成岩环境，硅质、高岭石等胶结物沉淀减孔约1.2%；长石、岩屑等溶蚀增孔约4.3%。最终，储层演化至现今孔隙度10.1%。 相似文献
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渤海海域旅大21构造沙四段水体环境对储层成岩作用及物性的影响 总被引：1，自引：1，他引：0
通过普通薄片、铸体薄片、扫描电镜、微量元素等分析对渤海海域旅大21构造水体环境及对储层成岩作用及物性的影响进行分析,分析认为研究区沙四段水体环境为半咸水背景下的淡水充注;岩石类型主要为岩屑长石砂岩,易溶组分较多。作为半咸水为主体的沉积环境导致其成岩流体主要为碱性流体,表现为发育石英溶解、长石加大、自生绿泥石等典型碱性成岩作用;此外不同时期的淡水注入使得发育高岭石等少量酸性流体的成岩现象;成岩流体演化经历了从碱性到酸性再到碱性的多期过程;对储层影响主要表现为碱性流体对储层的影响具有双重性,而酸性流体造成的溶蚀是物性改善的主要原因。 相似文献
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In the Tuoshi oilfield,located in the Cenozoic Jianghan Basin of southeastern China ,there have been found hydrocarbon reservoirs hosted in lacustrine sandstones of the Eogene Xingouzui Formation.The main diagenetic features identified in these sandstones include the dissolution of detrital K-feldspar and albite grains,the precipitation of quartz as overgrowths and /or cements ,and the precipitation and /or transformation of clay minerals.These diagenetic features were interpreted to have occurred in early,intermediate and late stages,based on the burial depth.The kinetics of fluid-mineral reactions and the concentrations of aqueous species au each stage of diagenesis were simulated numerically for these lacustrine sandstones,using a quasi-sta-tionary state approximation that incorporates simultaneous chemical reactions in a time-space continuum.During the early diagenetic stage,pore fluid was weakly acidic,which resulted in dissolution of K-feldspar and albite and,therefore,led to the release of K^ ,Na^ ,Al^3 and SiO2(aq) into the diagenetic fluid.The increased K^ ,Na^ ,Al^3 and SiO2(aq) concentrations in the diagenetic fluid caused the precipitation of quartz,kaolinite and illite.At the beginning of the intermediate diagenetic stage the concentration of H^ was built up due to the decomposition of organic matter,which was responsible for further dissolution of K-feldspar and albite and pre-cipitation of quartz,kaolinite,and illite.During the late diagenetic stage,the pore fluid was weakly alkaline,K-feldspar became stable and was precipitated with quartz and clay minerals.When the burial depth was greater than 3000 m,the pore fluids became supersaturated with respect to allbite,but undersaturated with respect to quartz,resulting in the precipitation of albite and the dissolution of quartz.The diagenetic reactions forecasted in the numerical modeling closely matched the diagenet-ic features identified by petrographic examination, and therefore,can help us to gain a better understanding of the diagenetic processes and associated porosity evolution in sandstone reservoirs. 相似文献
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孔隙衬里绿泥石的成因及对储层性能的影响 总被引：1，自引：0，他引：1
孔隙衬里绿泥石发育的砂岩大多属于优质储层,前人将其归功于绿泥石对孔隙的保护作用。按照孔隙衬里绿泥石形成的铁质来源,可划分为同沉积黏土膜转化型、富铁镁物质溶蚀再结晶型和转化与直接结晶混合型3种类型。通过国内外富孔隙衬里绿泥石砂岩实例的对比研究表明,孔隙衬里绿泥石可以通过抑制自生石英生长、提高抗压实能力、指示早期碱性溶蚀发育程度和堵塞孔喉等4种方式影响储层性能,且不同成因的孔隙衬里绿泥石对储层性能影响方式不同,同一成因绿泥石在不同成岩阶段的影响方式也不同。中成岩A期以前,转化型孔隙衬里绿泥石通过占据孔喉和提高抗压能力影响储层,而溶蚀结晶型孔隙衬里绿泥石主要指示火山物质发生碱性溶蚀的程度;只有砂岩成岩阶段达到中成岩B期以后,孔隙衬里绿泥石对石英生长的抑制作用才得到充分体现。 相似文献
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通过对川西坳陷新场气田上三叠统须家河组须四、须二段储集层成岩作用类型及其特征研究,认为储集层主要经历了压实压溶作用、自生矿物胶结作用和溶解作用3种类型。储集层成岩-储集相可以划分成5种,即强溶解成岩-储集相、绿泥石衬边粒间孔成岩-储集相、压实压溶成岩-储集相、碳酸盐胶结成岩-储集相和石英次生加大成岩-储集相。不同的储集层成岩-储集相由于经历了不同的成岩演化序列,使得储集层中的残余原生粒间孔和次生溶孔的形成条件各不一样,储集层中孔隙的保存主要决定于孔隙被压实、自生矿物的充填、多期的溶解作用等因素,并与孔隙中发育的绿泥石衬边有紧密联系。在上述5种成岩-储集相中,有效的成岩-储集相只有两种,即强溶解成岩-储集相和绿泥石衬边粒间孔成岩-储集相,它们对须家河组须四、须二段优质储层的形成起着至关重要的作用,而其它几种成岩-储集相对优质储层的形成是无效的。 相似文献
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X. L. Sun X. G. Zhang J. L. Lin Z. X. Zhao D. W. Huang 《Australian Journal of Earth Sciences》2013,60(8):1163-1174
AbstractThe characteristics and distribution of clay minerals and their effects on reservoir quality in the Huagang sandstones in the Xihu Sag, East China Sea Basin were studied by using X-ray diffraction, casting thin-sections, scanning electron microscopy, electron microprobe analysis, fluid inclusion analysis, constant-rate mercury injection and nuclear magnetic resonance. Clay minerals consist of kaolinite, chlorite, illite and illite–smectite mixed layer (I/S); kaolinite forms from dissolved feldspars, chlorite occurs as clay coatings that are transformed from clay precursors owing to the flocculation of suspended detrital clays or the crystallisation of pore fluids, and illite forms from the illitisation of detrital smectite, authigenic kaolinite and K-feldspars. Clay distribution is controlled by sedimentary environments, burial history and lithologies. Typical reservoirs in the western sub-sag are thin and developed in braided river facies at relatively shallow burial depths with clays dominated by kaolinite. However, typical reservoirs in the central inversion tectonic zone are thicker and developed in a braided delta front facies at deeper burial depths with clays mainly consisting of chlorite, illite and I/S. High-quality reservoirs are characterised by coarse granularity, high quartz content and low clay content with widespread development of chlorite coatings that inhibit quartz cements at low temperatures. At higher temperatures, the high-quality reservoirs develop more pores providing growth space for quartz cements and result in the coexistence of chlorite coatings and quartz cements. The high-quality reservoirs are controlled by their lithological characteristics rather than chlorite coatings. Illite and I/S clays create severe damage to reservoirs by reducing the size and connectivity of pore-throats. 相似文献
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鄂尔多斯盆地东部太原组碎屑岩中自生伊利石形成机制及其对储层形成的影响 总被引：2，自引：0，他引：2
鄂尔多斯盆地东部太原组砂岩骨架颗粒中几乎没有碎屑长石,残余的微量长石(在岩石中的平均含量为0.4%.低于X射线衍射检测限)主要为钾长石,同时具有较低的自生高岭石含量(1.02%)、很低的自生石英含量和同期火山物质含量,以及较高的自生伊利石含量(1.22%),这表明太原组的自生伊利石主要是在相对高温的深埋藏封闭条件下,通过钾长石溶解反应:钾长石+H~++H_2O→高岭石+硅质+K~+和高岭石伊利石化反应:高岭石+K~+→伊利石+H~++H_2O或其加和反应:钾长石+高岭石→硅质+伊利石+H_2O形成,后者通过消耗钾离子而克服钾长石溶解的动力学屏障,是前者的重要驱动反应,并向流体输出氢离子,因此对次生孔隙的形成、尤其是在相对深埋藏的成岩过程中与钾长石溶解有关的次生孔隙的形成具有显著的积极作用. 相似文献
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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
18.
成岩作用对河流-三角洲相砂岩储层物性演化的影响--以延长油区上三叠统延长组长2砂岩为例 总被引：52，自引：5，他引：52
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
19.
在岩心观察基础上,通过应用全岩主量元素分析、显微镜下常规与铸体薄片观察鉴定和定量统计、图像孔喉分析、物性测试、X-射线衍射分析、包裹体荧光分析、均一温度与激光拉曼探针成分分析等多种手段,研究了松辽盆地营城组火山岩岩性和火山岩储层成因; 结合成岩作用与储集空间特征研究,分析了火山岩储层孔隙演化过程。结果表明,火山岩经历了冷却成岩作用、岩浆期后热液作用、风化淋滤剥蚀作用以及埋藏成岩作用等4个成岩作用阶段。火山岩储层的形成、孔隙演化和储集性能的改善主要与火山岩在浅埋A期后期-深埋成岩B期成岩过程中的断裂、不整合面及构造裂缝的发育以及热液流体沿断层、不整合面和构造裂缝流动的过程中对火山岩产生溶蚀作用密切相关,营城组火山岩属于构造-岩性火山岩气藏。 相似文献