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1.
The objective of this study was to compare the laboratory slaking behavior of common clay-bearing rocks to their slaking behavior under natural climatic conditions observed during a 1-year experimental study. Five-cycle slake durability tests were performed in the laboratory on five claystones, five mudstones, five siltstones, and five shales. Twelve replicate specimens of each of these 20 rocks were also exposed to natural climatic conditions for 12 months. After each month of exposure, one replicate specimen of each rock was removed from natural exposure and its grain size distribution was determined. The results of laboratory tests and field experiment were compared in terms of 1st, 2nd, 3rd, 4th, and 5th cycle slake durability indices (Id1, Id2, Id3, Id4, Id5), grain size distribution of slaked material, and disintegration ratio (D R), where D R is the ratio of the area under the grain size distribution curve of slaked material for a given specimen to the total area encompassing all grain size distribution curves of the specimens tested. Correlations of Id1, Id2, Id3, Id4, and Id5 with D R values for laboratory specimens exhibit R 2 values of 0.87, 0.88, 0.83, 0.75, and 0.70, respectively. However, the relationship between Id2 and D R, determined after 1, 3, 6, and 12 months of natural exposure, becomes weaker with increasing time of exposure, with R 2 values of 0.65, 0.63, 0.63, and 0.25, respectively. The fifth-cycle slake durability index (Id5) for laboratory tested specimens shows a better correlation with D R values for naturally exposed specimens (R 2 up to 0.80). A comparison of grain size distribution curves of slaked material for laboratory specimens, after the 2nd cycle slake durability test, with those of specimens exposed to natural climatic conditions shows that the laboratory test underestimates the field durability for claystones, and overestimates it for siltstones. 相似文献
2.
Slake durability is an important geotechnical parameter and is a measure of degradability of rocks due to the process of mechanical and chemical breakdown. It is closely related to the mineralogical composition and the texture of the rocks. In this paper, mineralogical examination along with slake durability tests under variable pH conditions, both in acidic and alkaline environments, on the limestone, shale and siltsone were evaluated to understand the relationship between mineralogy and the degradability of rocks. The study revealed that rocks rich in calcium carbonate and or magnesium carbonate are adversely affected in the acidic environment, whereas, the rocks rich in quartz, feldspar and muscovite are independent of the pH of the slaking fluid, which in turn, is more influenced by the texture of the constituent minerals. It has also been observed that fine grained rocks are more susceptible to degrade in comparison to the coarse grained rocks. 相似文献
3.
Fluid metasomatic genesis of stratiform skarn in the Suoerkuduke Cu-Mo deposit,East Junggar,NW China
Stratiform skarns associated with ore deposits are widespread in the north of East Junggar, particularly in the Suoerkuduke Cu-Mo deposit. The Suoerkuduke stratiform and stratoid skarns are hosted by Devonian intermediate-mafic volcanic and pyroclastic rocks, mainly andesite, andesitic porphyry and tuffaceous sandstone, without carbonate or calcareous rocks. The skarns consist of dominant andradite-grossular, epidote, diopside-hedenbergite and minor actinolite, quartz, magnetite and metallic sulfides. The garnet and epidote composition, especially Fe3 + and Al contents, is largely a function of the bulk composition and physicochemical environment (particularly fO2) during crystallization. Such mineralogy indicates a relatively oxidizing environment and medium acidity of solution during skarnization.The Suoerkuduke skarns are distinct from typical contact metasomatic skarn in wall rock, as no carbonate or calcareous rocks were found, and differ in the distribution patterns of skarn zonation in that gradually weakened skarn zones are not quite symmetrically distributed on both sides of the alteration center (a garnet skarn). Abundant remnants of andesite, andesitic porphyry and tuffaceous sandstone in the weakened skarn zone indicate that the protolith of the skarn is andesite, andesitic porphyry and tuffaceous sandstone. Magmatic water, meteoric and seawater are involved in skarn alteration. Moyite and granitic porphyry are not coeval with skarn, and their emplacement resulted in the hornfelization of wall rock instead of skarnization, and themselves keep away from skarn alteration. Therefore, there was probably a huge batholith supplying magmatic fluid for skarn formation. Mass balance estimates suggest that hydrothermal fluid must contribute a portion of Ca and Fe to ensure sufficient supply for skarn formation in the absence of local carbonate and calcareous rocks. In conclusion, the stratiform skarns in the Suoerkuduke are products of intermediate-mafic volcanic and pyroclastic rocks metasomatised by hydrothermal fluid that probably leached calcareous wall rock during ascent. 相似文献
4.
Comparison of three artificial neural network approaches for estimating of slake durability index 总被引：1，自引：1，他引：0
Slake durability index (I d2) is an important engineering parameter to assess the resistance of clay-bearing and weak rocks to erosion and degradation. Standard test sample preparation for slake durability test is difficult for some rock types and the test is time-consuming. The paper reports an attempt to define I d2 using other parameters that are simpler to obtain. In this study, three different artificial neural network approaches, namely feed-forward back propagation (FFBP), radial basis function based neural network (RBNN), and generalized regression neural networks (GRNN) were used for estimating I d2. The determination coefficient (R 2), root mean square error and mean absolute relative error statistics were used as evaluation criteria of the FFBP, RBNN, and GRNN models. The experimental results were compared with these models. The comparison results indicate that the GRNN models are superior to the FFBP and RBNN models in modeling of the slake durability index (I d2). 相似文献
5.
Slake durability of rocks is a vital engineering geological property of rock materials that has an important role in the promotion of slope stability, evaluation of rock materials, as well as the estimation of stone degradability. This parameter is related to such factors as mineralogy, physical characteristics of rocks, and the environmental conditions. A major part of south and southwestern Iran embraces the Aghajari Formation whose sandstones are used to form the foundations for some structures in Khouzestan province where they are being extensively used as aggregate(s). In this paper, tests of mineralogical examinations, physical properties, and slake durability of sandstones from Ahwaz and Haftkel anticlines were administered in order to assess the durability and degradability of these rocks. The rock durability of each type was evaluated to be up to 15 cycles in acidic and alkaline watery environments and salt aqueous solutions. The results showed that durability of sandstones under study is related to their petrographical and physical characteristics. The durability index of the sandstone samples was decreased by pH reduction and by increasing the concentration of aqueous solutions. The durability index of Ahwaz samples, too, was decreased in basic solutions while this index increased for Haftkel sandstones with the increase in the pH of solutions. Also, the obtained results illustrated that durability index decreased with the increase in the number of cycles. Based on the results, all sandstones show that the durability in sodium sulfate solution is much lower than that for the sodium chloride. Moreover, the slake durability index of the sandstones is decreased with an increase in the concentration of aqueous solutions. As a final statement, the Ahwaz sandstones show lower resistance to weathering processes than Haftkel sandstones; therefore, the use of rocks as building stones is not recommended here. 相似文献
6.
Slake durability study of shaly rock and its predictions 总被引：2，自引：0，他引：2
More than 35% of the earths crust is comprised of clay-bearing rocks, characterized by a wide variation in engineering properties and their resistance to short term weathering by wetting and drying phenomenon. The resistance to short-term weathering can be determined by slake durability index test. There are various methods to determine the slake durability indices of weak rock. The effect of acidity of water (slaking fluid) on slake durability index of shale in the laboratory is investigated. These methods are cumbersome and time consuming but they can provide valuable information on lithology, durability and weather ability of rock. Fuzzy set theory, Fuzzy logic and Artificial Neural Networks (ANN) techniques seem very well suited for typical complex geotechnical problems. In conjunction with statistics and conventional mathematical methods, a hybrid method can be developed that may prove a step forward in modeling geotechnical problems. During this investigation a model was developed and compared with two other models i.e., Neuro-fuzzy systems (combination of fuzzy and artificial neural network systems) and artificial neural network system, for the prediction of slake durability index of shaly rock to evaluate the performance of its prediction capability. 相似文献
7.
Argillaceous rocks cover about one thirds of the earth's surface. The major engineering problems encountered with weak- to medium-strength argillaceous rocks could be slaking, erosion, slope stability, settlement, and reduction in strength. One of the key properties for classifying and determining the behavior of such rocks is the slake durability. The concept of slake durability index (SDI) has been the subject of numerous researches in which a number of factors affecting the numerical value of SDI were investigated. In this regard, this paper approaches the matter by evaluating the effects of overall shape and surface roughness of the testing material on the outcome of slake durability indices.
For the purpose, different types of rocks (marl, clayey limestone, tuff, sandstone, weathered granite) were broken into chunks and were intentionally shaped as angular, subangular, and rounded and tested for slake durability. Before testing the aggregate pieces of each rock type, their surface roughness was determined by using the fractal dimension. Despite the variation of final values of SDI test results (values of Id), the rounded aggregate groups plot relatively in a narrow range, but a greater scatter was obtained for the angular and subangular aggregate groups. The best results can be obtained when using the well rounded samples having the lowest fractal values. An attempt was made to analytically link the surface roughness with the Id parameter and an empirical relationship was proposed. A chart for various fractal values of surface roughness to use as a guide for slake durability tests is also proposed. The method proposed herein becomes efficient when well rounded aggregates are not available. In such condition, the approximate fractal value for the surface roughness profile of the testing aggregates could be obtained from the proposed chart and be plugged into the empirical relation to obtain the corrected Id value. The results presented herein represent the particular rock types used in this study and care should be taken when applying these methods to different type of rocks. 相似文献
8.
泥质膨胀岩崩解物粒径分布与膨胀性关系试验研究 总被引：2，自引：0，他引：2
崩解性是膨胀岩最基本的特性之一,但在膨胀岩膨胀性的快速判别指标中少见关于崩解性及崩解物的定量指标。因此,有必要开展膨胀岩崩解物粒径分布特征和崩解性与膨胀性之间关系的研究,以对膨胀岩的快速判别进行补充。以浙江台州黑洞、蛇蟠岛和新疆大阪隧洞泥质岩样品为例,进行了干燥饱和吸水率和干燥饱和崩解试验,并分析了干燥崩解物粒径分布特征、耐崩解性指数及其与基于干燥饱和吸水率的膨胀性判别结果之间的关系。结果表明,膨胀岩膨胀性的强弱与其崩解物的最大含量粒组颗粒粒径、有效粒径和耐崩解性指数呈反相关关系。膨胀岩崩解物粒径分布的差异性对其膨胀性具有一定的指示意义。 相似文献
9.
《Engineering Geology》2000,57(3-4):215-237
Weathering can induce a rapid change of rock material from initial rock-like properties to soil-like properties. The resistance of a rock to short-term weathering is described through a durability parameter called the slake durability index. As durability is an important engineering parameter, particularly for weak and clay-bearing rocks, it was assessed by a number of tests. The main purpose of this study is to assess the influence of the number of drying and wetting cycles and controls of mineralogical composition and strength on durability. For this purpose, 141 samples of different types of weak and clay-bearing rocks were selected from different parts of Turkey, and relationships between the above-mentioned rock characteristics were statistically investigated. The samples were subjected to multiple-cycle slake durability testing, X-ray diffraction (XRD) analysis and uniaxial compression testing. In addition, to assess the influence of mineralogical composition on durability, the mineral contents of the original material and the material passing from the drum of the slake durability apparatus after each cycle were also determined by XRD. The results indicate that the type and amount of clay minerals are the main factors influencing the variations of the slake durability index in all samples. The durability of the clay-bearing rocks studied correlates best with the amount of expandable clay minerals. A strong relationship between the uniaxial compressive strength and the fourth-cycle slake durability index is found only for the marls among the rock types studied. Assessment of gradation results of the spoil pile materials consisting of clay-bearing rocks also reveals that the increase in percentage of fines in old piles is indicative of material degradation, as is evident by multiple-cycle slaking. It is emphasized that two-cycle conventional slake durability testing did not appear to offer an acceptable indication of the durability of weak and clay-bearing rocks when compared with multiple-cyclic wetting and drying. Comments on the performance of the test are made that aim to make the testing process and interpretation of the results more reliable. 相似文献
10.
Diagenesis of a mixed siliciclastic/evaporitic sequence of the Middle Muschelkalk (Middle Triassic), the Catalan Coastal Range, NE Spain 总被引：1，自引：0，他引：1
S. MORAD I. S. AL-AASM† F. J. LONGSTAFFE‡ R. MARFIL§ L. F. DE ROS H. JOHANSEN¶ M. MARZO 《Sedimentology》1995,42(5):749-768
The Middle Muschelkalk (Middle Triassic) of the Catalan Coastal Range (north-east Spain) comprises sandstone, mudstone, anhydrite and minor carbonate layers. Interbedded sandstones and mudstones which are dominant in the north-eastern parts of the basin are terminal alluvial fan deposits. South-westward in the basin, the rocks become dominated by interbedded evaporites and mudstones deposited in sabkha/mudflat environments. The diagenetic and pore water evolution patterns of the Middle Muschelkalk suggest a strong facies control. During eodiagenesis, formation of microdolomite, anhydrite, baryte, magnesite, K-feldspar and mixed-layer chlorite/smectite was favoured within and adjacent to the sabkha/mudflat facies, whereas calcite, haematite, mixed-layer illite/smectite and quartz formed mainly in the alluvial facies. Low δ18OSMOW values for microdolomite (+23.7 to +28.4%) and K-feldspar overgrowths (+17.3 to +17.7%) suggest either low-temperature, isotopic disequilibrium or precipitation from low-18O porewaters. Low-18O waters might have developed, at least in part, during low-temperature alteration of volcanic rock fragments. During mesodiagenesis, precipitation of quartz overgrowths and coarse dolomite occurred in the alluvial sandstones, whereas recrystallization of microdolomite was dominant in the sabkha/mudflat facies. The isotopic compositions of these mesogenetic phases reflect increasing temperature during burial. Upon uplift and erosion, telogenetic calcite and trace haematite precipitated in fractures and replaced dolomite. The isotopic composition of the calcite (δ18OSMOW=+21.5 to +25.6%o; δ13C= 7.7 to - 5.6%o) and presence of haematite indicate infiltration of meteoric waters. 相似文献
11.
海拉尔盆地乌尔逊-贝尔凹陷下白垩统发育火山熔岩-正常碎屑沉积岩之间的过渡岩石类型,其成岩作用类型与正常沉积岩相比具有特殊性.采用显微镜下描述与扫描电镜分析相结合的方法对研究区成岩作用类型进行了研究,并总结出成岩作用序列.结果显示火山碎屑岩的成岩作用类型包括熔结作用、机械渗滤作用、压实作用、脱玻化作用、重结晶作用、胶结作用、自生矿物转化和溶蚀溶解作用.其中,熔结作用、脱玻化作用以及凝灰质的溶蚀溶解作用是火山碎屑岩所特有的成岩作用类型.研究区具有成因联系的成岩共生组合主要有4类,分别是:(1)微晶石英和微晶方解石;(2)石英的溶解与结晶;(3)自生白云母、蒙皂石、伊利石和绿泥石;(4)沸石与自生长石.成岩序列可以分为熔结作用阶段、机械渗滤作用阶段、脱玻化作用阶段、凝灰质溶蚀溶解作用阶段、粘土矿物混层阶段、自生白云母阶段、沸石胶结阶段、颗粒强烈胶结阶段以及铁白云发育阶段.研究区下白垩统处于早成岩B期至晚成岩B期,主要为晚成岩A期. 相似文献
12.
We determined the rock types, the authigenic minerals, the paragenetic sequence, and the origin of dawsonite in pyroclastic rocks from the Yimin Formation of Beier Sag in the Hailar Basin, China. Dawsonite, a diagenetic mineral, is thought to result from a large influx of CO2 and, therefore, this system represents a natural analogue for in-situ mineral carbon storage. The studied host rocks are mainly tuffs/tuffaceous sandstones which now contain up to 70 vol% authigenic carbonates, including dawsonite, ankerite, and siderite. The initial alteration of the tuffs yielded minor siderite. Kaolinite, illite and mixed illite/smectite then formed as product phases. Dawsonite and quartz subsequently precipitated in response to CO2 influx apparently coupled to feldspar and perhaps kaolinte dissolution. Dawsonite reaches a maximum 25 vol% of the bulk rock. Mass balance suggests that this CO2 influx was coupled to the external import of sodium and export of SiO2. Ankerite and additional siderite precipitated during the late-stage alkaline diagenesis. The carbon isotope values of the dawsonite are in the range −4.1‰ to −2.2‰, indicating the magmatic origin of the CO2. Vitrinite reflectance and thermal gradient constraints suggest that the dawsonite at this location formed at a temperature of ∼75 °C. 相似文献
13.
苏尼特左旗达来苏木地区位于中亚造山带东南部,索伦缝合带之北,发育特征性的下泥盆统敖包亭浑迪组变火山-沉积岩系。这套地层主要由安山岩、凝灰质砂岩、砂岩、粉砂岩以及火山碎屑岩等组成,磨圆度较差,具有近源沉积特征。地球化学分析结果显示,砂岩的SiO_2和K_2O含量中等,Na_2O含量较高,Fe_2O_3和MgO含量较低;微量元素蛛网图呈右倾型,含量和变化趋势与上地壳相似;稀土元素配分特征显示轻稀土富集、重稀土亏损,(La/Yb)N平均为6.44,负Eu异常明显(Eu/Eu*平均为0.72)。综上并结合区域分析显示砂岩形成于活动大陆边缘和大陆岛弧,源岩主要为英安岩和部分安山岩,进而推测在早泥盆世古亚洲洋仍处于向北俯冲的构造环境,敖包亭浑迪组的物源应主要为北部的乌里雅苏台地区上地壳长英质岩系。 相似文献
14.
Texture and grain size is of great importance in understanding the mechanical properties of rocks. The aim of this study was to investigate textural and slaking durability characteristics, and correlate them with the gypsum types where the dolines occurred, with particular reference to the texture and crystal size. The investigation comprised two stages: field work and laboratory testing. Initially, rock samples were obtained from various representative karstified and non-karstified locations. Thereafter, mineralogical, physical and slaking durability characteristics of the gypsum samples were determined by means of laboratory testing. After the field and laboratory works, the geological, mineralogical and slaking durability characteristics of the study area gypsum were reviewed and discussed from the point of view of doline formation. Results showed that fine grain sized alabastrine gypsum tends to be karstified and leads to doline formation. This is closely related to the crystal size, texture and attributable to the slaking durability of the gypsum. Consequently, the results demonstrate that the texture, especially crystal size, and effective porosity are important parameters controlling the slake durability of the gypsum and doline formation. 相似文献
15.
1IntroductionTheHongshijinggolddepositislocatedinthenorthofLuobupouLakeofRuoqiang ,about 30 0kmsouthwestofHamiCity ,Xinjiang .ItwasdiscoveredbytheSixthGeologicalTeamofXinjiangduringgeo chemicalexploration .TheHongshijinggolddeposit,whichoccursinthegold bearingformationcomposedofMiddleandLateCarboniferousvolcanicandpyroclasticrocks ,isabrittle ductileshearzonetypegolddepositcontrolledbyariftbelt.TheHongshijinggolddepositislocatedinthesouthwestoftheHongshi jing -Maotoushanmineralizationb… 相似文献
16.
为解决火山碎屑岩在钻进中易剥落、易崩塌的问题,探讨钻井液性能对火山碎屑岩崩解性的影响,以青海阿克楚克塞矿区火山碎屑岩为例,分析了其岩石样品的矿物成分,进行了岩石样品烘干和浸水循环实验,采用多元线性回归分析法分析了原1#、2#钻井液的主要参数和耐崩解性指数之间的关系。结果表明,钻井液的动塑比、静切力、失水量和漏斗黏度4项性能指标与火山碎屑岩崩解性的相关性可达83.37%,其中动塑比对火山碎屑岩崩解性的影响尤为显著。通过调整水解聚丙烯酰胺和褐煤树脂质量分数提高了钻井液的动塑比和稳定性,从而获得优选钻井液配方：水+4%膨润土+3% Na2CO3+0.1% NaOH+0.15% MV-CMC（中黏钠羧甲基纤维素）+0.5% LV-CMC（低黏钠羧甲基纤维素）+2% SPNH（褐煤树脂）+0.08% PHP（水解聚丙烯酰胺）。现场应用表明,钻进至429.00 m深度时使用优选钻井液孔底沉渣厚度较1#钻井液降低了89.7%,较2#钻井液降低了80.3%。 相似文献
17.
Isotopic and mineralogic data from an 8500-m thick section of the Great Valley sequence, northern California, indicate that changes in the δ18O values of authigenic minerals resulted from the conversion of smectite to a 10 Å clay-mineral as temperature increased with burial in the Jurassic- Cretaceous outer-arc basin. The clay-mineral assemblage in mudstone is characterized by a proportional increase of the 10 Å clay-mineral with increasing stratigraphic depth, and by a depletion in the δ18O value of the mixed-layer smectite/10 Å clay-mineral with descending stratigraphic position from +21.9 to + 15.5%. SMOW. Modeling of the oxygen isotopic data from authigenic phases, based on equilibrium fractionation during clay-mineral diagenesis, indicates that δ18O values of calcite in mudstones and of calcite cements in sandstone precipitated along a temperature gradient of about 25°C/km during maximum burial to about 6–7 km. δD values of the mixed-layer smectite/10 Å clay-mineral range between ?69 to ?44%. SMOW. Using temperatures calculated from the oxygen isotopic data, the deuterium and oxygen isotopic data indicate that the smectite underwent late-stage dehydration and probably buffered the composition of formation waters from sea water values to isotopic compositions of δ18O ≈ +8%. SMOW and δD ≈ ?25%. SMOW. The δ13C values of calcite from mudstone and sandstone imply that crystallization of authigenic calcite was linked to organic diagenesis during which dissolved HCOt-3 was continuously enriched in 13C as temperature increased with burial. At the base of the sequence and immediately overlying the ophiolitic basement rocks, several hundred meters of strata were altered by more oxygen-depleted (δ18O ? +4 to +5%.) hydrothermal fluids emanating from the ophiolitic rocks, probably at maximum burial depth. 相似文献
18.
Study on the physical disintegration characteristics of Subang claystone subjected to a modified slaking index test 总被引：2，自引：0，他引：2
Some instability problems were found on natural or engineered slopes mostly lying on Subang claystones. The instability problems included excessive erosion, slumps and rock falls. The field performance surveys of the problems suggested that the claystones physically weather rapidly so that the rock properties they exhibit during excavation often change to properties with a more characteristic of soil. Such a phenomenon is generally known as a slaking process. In order to gain better understanding about the slaking of Subang claystones, a series of experimental laboratory studies were carried out involving a modified slaking index test. Claystone samples used in this study were obtained from their exposures along the Northern West Java area of Indonesia. Petrographic analysis was correspondingly performed to identify mineral and texture/fabric, and in turn, to determine the inherent factors of the rocks which might affect the slaking process. The stssudy results indicated that the claystones were characterized by high to very high slaking properties having a maximum slaking index (Is) of 57.4% and a mean Is of 43.8%. Major dispersion slaking on sample surfaces and high cracking in response to excessive swelling were recognized as main slaking modes within the claystones. All samples lose progressively less material through the five wet–dry cycles of a slaking index test, indicating a decelerated slaking rate. It was evident that the main inherent factors controlling the slaking process were expandable clay mineral smectite, non-clay mineral pyrite and soluble mineral calcite. Moreover, a quite important of inherent bonding material and stress release energy in the slaking characteristics of the claystones was revealed by a closure phase of an initial hairline crack during unloading. 相似文献
19.
According to differences in features of illites including spatial distribution, crystallinity index, volume of swelling layer, polytype and relationship between its index and copper grade, two typical kinds of illite can be classified within the Tongchang porphyry copper deposit, Dexing County, East China. One is a kind of hydrothermally altered minerals within the hydrothermal alteration zone, including altered granodiorite-porphyry and altered metamorphic tuffaceous phyllite near the contact zone with porphyry rockbody. The illite crystallinity and expandability are mainly affected by water/rock ratio or fluid flux, and hydrothermal illite is formed by illitization of plagioclase and/or micas during hydrothermal fluid evolution within the porphyry body and near the contact zone with wall rocks. The other is a product of low-grade metamorphism itself by illitization of smectite, whose crystallinity index is lower than the hydrothermal illite and which is of 2M1 polytype with no swelling layer, in the altered metamorphic tuffaceous phyllite far from porphyry rockbody ( > 2 km). Moreover, the negative correlation between illite index and copper grade indicates that, within the alteration zone, the smaller the illite crystallinity, the stronger the alteration degree, and the higher the copper grade due to higher water/rock ratio. At lower levels of the porphyry body, however, the illite crystallinity (IC) values are controlled mainly by temperature and time. 相似文献
20.
以塔木察格盆地塔南凹陷铜钵庙组-南屯组火山碎屑岩为例,结合岩石学观察、薄片鉴定、扫描电镜分析等技术手段,研究火山碎屑岩储层特征及其影响因素。综合研究认为: 火山碎屑岩岩石类型主要包括凝灰岩( 熔结凝灰岩) 、沉凝灰岩和凝灰质砂( 砾) 岩; 发育有原生孔隙、原生裂缝、次生孔隙、次生裂缝等4 类10 种储集空间,且以次生溶孔为主; 属于中低孔--特低渗型储层,横向上靠近洼陷边缘、接近构造高部位的孔隙度和渗透率较高,纵向上在1 900 ～ 2 100 m、2 600 ～ 2 900 m 处存在两个明显的异常高孔隙带; 储集性能受岩性岩相、构造运动、成岩作用和有机质热演化等因素影响,其中岩性岩相和成岩作用是影响储层储集性能的主要影响因素。 相似文献