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1.
淮南煤田煤层气成藏动力学系统的机制与地质模型研究 总被引：4，自引：0，他引：4
淮南煤田由次生生物成因和热成因气组成的混合型煤层气藏,受各种地质和水文地质条件的影响和控制。本文通过热流场和地温场、古构造应力场和原地应力场以及地下水动力场的系统分析,探讨了煤层气成藏动力学系统的形成机制,进而提出了相应的成藏地质模型。淮南煤田的煤层气藏虽然属向斜式(或盆心)聚气模型,但是,该模型强调,作为附加气源的次生生物气的补充,成藏动力学系统演化、构造样式和能量场的耦合关系,是混合型煤层气富集成藏的主因。 相似文献
2.
K. L. Pinetown 《Australian Journal of Earth Sciences》2014,61(3):409-426
Basin modelling has been used to improve understanding of the origin and temporal evolution of coal seam gas in the Hunter Coalfield of the Sydney Basin. Burial history models were produced based on data from seven boreholes located in the southern, eastern, central and western areas of the coalfield. Mean random vitrinite reflectance (Rv,r) data, derived from measurements of mean maximum reflectance (Rv,max), were used for calibration of the models. A qualitative sensitivity analysis of one model shows that varying the paleoheat flow has a greater influence on calculated Rv,r than varying the eroded overburden thickness.The differences between the constructed models are significant enough to provide plausible explanations for regional gas distribution in the Hunter Coalfield. Coals in the south of the coalfield appear to have the greatest potential for thermogenic gas generation. Modelling has shown that areas that have low gas contents and decreased permeability have been uplifted more, and buried less, compared with areas that have high gas contents. Burial history modelling shows noticeable variations in the extent of burial and uplift, and, consequently, in thermal maturities and potential for thermogenic gas generation; together with the assessment of other coal and gas property data, it appears that present-day gas contents may partially reflect coal ranks and adsorption capacities, with late-stage biogenic gas generation replenishing CH4 volumes that were lost following uplift during the Late Cretaceous. 相似文献
3.
Coalbed methane (CBM) is a kind of burgeoning and enormously potential clean energy resource, and the temperature of the thermogenic
CBM generation is close to that of the partial annealing zone (PAZ) of apatite fission tracks (AFT). In this study the thermo-tectonic
history of the Huainan Coalfield and the potential CBM resource were studied and discussed by using the AFT method.
The AFT data indicate that the apparent ages of AFT vary from 45.5 to 199.1 Ma. They are younger than the ages of their host
strata (255–1800 Ma) except one sample, and the single-grain ages of AFT can be classified as a single age group for each
sample. In combination with the geological setting, modeling results of the AFT ages, average lengths, and the thermal history
based on the AFT single-grain ages and length distributions, some preliminary conclusions can be drawn as follows: (1) at
least three thermo-tectonic events (in the periods of ∼240, 140 and 80 Ma, respectively) have occurred in the study area since
the Late Paleozoic. The occurrence of both the first (during 240–220 Ma) and second (during 160–120 Ma) thermo-tectonic events
is possibly responsible for the establishment of the patterns of gas generation and reservoir formation. The second thermo-tectonic
event also led to slight accumulation of hydrocarbons and generation of thermogenic gas; (2) the AFT ages of most coal-bearing
strata lie between 50 and 70 Ma. They should represent the cooling ages and the ages of inferred uplift and denudation, as
well as the possible CBM release history. Therefore, the maximum burial depth of coal-bearing strata and the denudation thickness
of the overlying strata are over 3000 and 2000 m in the Upper Cretaceous and Paleogene series, respectively; and (3) subsequently,
a spot of secondary biogenic and scarcely thermogenic gas generation occurred due to negligible sedimentation during the Neogene
and Quaternary periods. Thus, it can be presumed that subsequent tectonism would destroy the CBM reservoir after its formation
in the Huainan Coalfield, especially in its structural development region. These AFT data may be helpful for a better understanding
of the thermo-tectonic history of the Huainan Coalfield, as well as of CBM generation, storage and release in the Huainan
Coalfield. 相似文献
4.
The molecular and stable isotope compositions of coalbed gases from the Upper Carboniferous strata and natural gases accumulated within the autochthonous Upper Miocene Skawina Formation of the D?bowiec-Simoradz gas deposit were determined, as well as the chemical and stable isotope compositions of waters from the Skawina Formation and waters at the top of the Upper Carboniferous strata of the Kaczyce Ridge (the abandoned “Morcinek” coal mine) in the South-Western part of the Upper Silesian Coal Basin. Two genetic types of natural gases within the Upper Carboniferous coal-bearing strata were identified: thermogenic (CH4, small amounts of higher gaseous hydrocarbons, and CO2) and microbial (CH4, very small amounts of ethane, and CO2). Thermogenic gases were generated during the bituminous stage of coalification and completed at the end of the Variscan orogeny. Degassing (desorption) of thermogenic gases began at the end of late Carboniferous until the late Miocene time-period and extended to the present-day. This process took place in the Upper Carboniferous strata up to a depth of about 550 m under the sealing Upper Miocene cover. A primary accumulation zone of indigenous, thermogenic gases is present below the degassing zone. Up to 200 m depth from the top of the Upper Carboniferous strata, within the weathered complex, an accumulation zone of secondary, microbial gas occurs. Waters within these strata are mainly of meteoric origin of the infiltration period just before the last sea transgression in the late Miocene and partly of marine origin having migrated from the Upper Miocene strata. Then, both methanogenic archaebacteria and their nutrients were transported by meteoric water into the near-surface Carboniferous strata where the generated microbial CH4 saturated coal seams. Waters within the Miocene strata of the D?bowiec-Simoradz and Zab?ocie are of marine origin, and natural gases accumulated within autochthonous Miocene strata of the D?bowiec-Simoradz gas deposit were most probably generated by microbial processes of on organic matter dispersed within the strata, though some contribution of gases migrating from the Carboniferous coal-bearing strata cannot be excluded. 相似文献
5.
鄂尔多斯盆地东北缘保德地区煤层气成因 总被引：3，自引：0，他引：3
鄂尔多斯盆地东北缘保德地区煤层气井组试采取得较好效果,但煤层气成因尚未形成统一认识,影响到对区域煤层
气勘探开发潜力的进一步认识。本文基于各类煤层气样品组分和稳定同位素的分析,对其成因进行了探讨。结果表明,煤
层气组分以甲烷为主,重烃浓度极低;δ13CCH4明显偏轻,部分δ13CCH4和δDCH4分布在热成因与二氧化碳还原型生物成因气过
渡区间;δ13CCO2相对较重,且与δ13CCH4之间存在负相关关系。分析认为,该区煤层气具有混合成因,以热成因气为主,兼
具生物成因气的特征,生物甲烷形成于二氧化碳还原途径,煤层水的化学和动力条件以及煤岩孔渗条件有利于产甲烷菌的
大量繁殖。 相似文献
6.
R.M. Bustin 《International Journal of Coal Geology》1984,4(1):21-44
The only significant deposits of anthracite and meta-anthracite in Canada occur in Upper Jurassic-Lower Cretaceous strata of the Groundhog coalfield in northcentral British Columbia. The coal rank in the coalfield varies from low volatile bituminous (1.70% R0 max) to meta-anthracite (5.8% R0 max). The main coal bearing unit, the Currier, includes up to 17 seams of anthracite and meta-anthracite most of which are less than 1 m thick. In the McEvoy unit, which overlies the Currier, up to 9 coal seams, mainly of semi-anthracite, occur that are up to 0.8 m thick. The coals are variably argillaceous, locally sheared and cut by quartz and less commonly, by carbonate veins. Coalification gradients in the coalfield vary from 0.8% to 3.0% R0 max km?1. The rank of coal within both the McEvoy and Currier units appears to increase towards the eastern edge of the coalfield.The level of coalification and the coalification gradients in the coalfield are anomalously high considering an indicated maximum depth of burial of 3500 m. From comparison with coalification models it appears that geothermal gradients in the order of 50° to 70°C/km must have existed for a period of time measured in millions of years. Studies to date suggest the coalification is pre-tectonic and thus pre-Late Cretaceous although there is some evidence for high heat flow in the Tertiary. The origin of the high heat flow may be related to intrusion accompanying collision of the Stikine terrain with the early Mesozoic margin of North America and/or high heat flux over an easterly dipping subduction zone below the Coastal volcanic-plutonic arc to the west. 相似文献
7.
低煤阶煤层气作为一种非常规天然气资源,具有良好的勘探开发前景。我国低煤阶煤层气资源丰富,进行低煤阶煤层气系统演化分析,对其富集成藏及开发具有重要的理论意义。鄂尔多斯盆地煤层甲烷的碳同位素δ13C1为–33.1‰~–80.0‰,氢同位素δCH4为–235‰~–268‰。该盆地侏罗系煤层气藏主要有次生生物气与热成因气构成的混合型煤层气藏和热成因气藏两种类型。据构造热事件、煤层气组分及成因,结合不同阶段的煤层埋深、变质程度和生气特征等,将鄂尔多斯盆地侏罗系低煤阶煤层气系统演化划分为4个阶段:煤系浅埋–原生生物气阶段﹑煤系深埋–热成因气阶段﹑煤系抬升–吸附气逃逸散失阶段﹑煤系局部沉降–次生生物气补充阶段。其中,煤系深埋–热成因气阶段和局部沉降–次生生物气阶段是低煤阶煤层气资源的主要形成阶段。次生生物气的补充是鄂尔多斯盆地侏罗系低煤阶煤层气成功开发的重要气源。鄂尔多斯盆地侏罗系煤层气藏应属于单斜式富气成藏模式。 相似文献
8.
A large suite of natural gases (93) from the North West Shelf and Gippsland and Otway Basins in Australia have been characterised chemically and isotopically resulting in the elucidation of two types of gases. About 26% of these gases have anomalous stable carbon isotope compositions in the C1–C4 hydrocarbons and CO2 components, and are interpreted to have a secondary biogenic history. The characteristics include unusually large isotopic separations between successive n-alkane homologues (up to +29‰ PDB) and isotopically heavy CO2 (up to +19.5‰ PDB). Irrespective of geographic location, these anomalous gases are from the shallower accumulations (600–1700 m) where temperatures are lower than 75°C. The secondary biogenic gases are readily distinguishable from thermogenic gases (74% of this sample suite), which should assist in the appraisal of hydrocarbons during exploration where hydrocarbon accumulations are under 2000 m. While dissolution effects may have contributed to the high 13C enrichment of the CO2 component in the secondary biogenic gases, the primary signature of this CO2 is attributed to biochemical fractionation associated with anaerobic degradation and methanogenesis. Correlation between biodegraded oils and biodegraded “dry” gas supports the concept that gas is formed from the bacterial destruction of oil, resulting in “secondary biogenic gas”. Furthermore, the prominence of methanogenic CO2 in these types of accumulations along with some isotopically-depleted methane provides evidence that the processes of methanogenesis and oil biodegradation are linked. It is further proposed that biodegradation of oil proceeds via a complex anaerobic coupling that is integral to and supports methanogenesis. 相似文献
9.
国际煤层气组成和成因研究 总被引：15，自引：0，他引：15
煤层气已成为一种新兴的非常规天然气资源。煤层气是成煤物质在煤化过程中生成并储集于煤层中的气体。按其成因类型分为生物成因气和热成因气。生物成因气有原生和次生两种类型,原生生物成因气一般在低级煤中生成,很难保存下来。次生生物成因气常与后来的煤层含水系统的细菌活动有关。热成因煤层气的生成始于高挥发份烟煤（Ro＝０.5％～0.8％）。与分散的Ⅰ／Ⅱ型或Ⅲ型干酪根生成的气体相比,煤层气的地球化学组成变化较大,反映了控制煤层气组成和成因的因素多而复杂,主要的影响因素包括煤岩组分、煤级、生气过程和埋藏深度及相应的温度压力条件。此外,水动力等地质条件和次生作用等也影响着煤层气的组成。 相似文献
10.
山东济宁煤田(东区)晚古生代孢粉组合 总被引：7，自引：0，他引：7
鉴定了山东济宁煤田(东区)晚古生代孢粉组合中的孢粉化石70属189种.据孢粉化石在地层中的分布和垂向的变化规律自上而下建立了5个孢粉组合:Ⅴ. Cyclogranisporites pressus-Lycospora pellucida组合, Ⅳ. Granulatisporites piroformis组合,Ⅲ. Sinulatisporites sinensis组合,Ⅱ. Thymospora pseudothiessenii-T. thiessenii组合,Ⅰ. Densosporites annulatus组合.通过与邻区及华北部分地区对比,确定本区孢粉组合的地质时代应为:晚石炭世晚期(组合Ⅰ),早二叠世早期(组合Ⅱ),早二叠世中期(组合Ⅲ),早二叠世晚期(组合Ⅳ)和晚二叠世早期(组合Ⅴ),本区石炭系-二叠系界线应置于太原组第11层灰岩之底. 相似文献
11.
The hydrogen and carbon isotopic composition of methane from natural gases of various origins 总被引：1，自引：0，他引：1
Martin Schoell 《Geochimica et cosmochimica acta》1980,44(5):649-661
The deuterium concentrations (δD vs SMOW) of biogenic methanes from world-wide occurrences range from ?180 to ?280%. and were found to be depleted in deuterium by approx. 160%. compared to the deuterium concentration of their associated waters. Theoretical considerations support this relationship to be the result of bacterial transformation of CO2 to methane and is therefore indicative of the biogenic origin of methane.Thermogenic gases with high C2+ concentrations (wet gases associated with crude oil) have D/H ratios from ?260 to ?150%. with deuterium contents tending to increase with decreasing wetness. Dry gases which are not associated with petroleum are more enriched in deuterium (?180 to ?130%.) and show an increase in deuterium with increasing rank of the source beds as it is similarly known for carbon-13.Many dry gases in young sedimentary basins were found to contain significant amounts of C2+ hydrocarbons. These gases cannot be grouped with either the biogenic or thermogenic gases and their methane is concluded to be of mixed biogenic and thermochemical origin.Using a diagrammatic display of the isotope data of methanes the various genetic groups of natural gases can be defined more clearly. 相似文献
12.
The petroleum generation potential and effective oil window of humic coals related to coal composition and age 总被引：1，自引：0，他引：1
A worldwide data set of more than 500 humic coals from the major coal-forming geological periods has been used to analyse the evolution in the remaining (Hydrogen Index, HI) and total (Quality Index, QI) generation potentials with increasing thermal maturity and the ‘effective oil window’ (‘oil expulsion window’). All samples describe HI and QI bands that are broad at low maturities and that gradually narrow with increasing maturity. The oil generation potential is completely exhausted at a vitrinite reflectance of 2.0–2.2%Ro or Tmax of 500–510 °C. The initial large variation in the generation potential is related to the original depositional conditions, particularly the degree of marine influence and the formation of hydrogen-enriched vitrinite, as suggested by increased sulphur and hydrogen contents. During initial thermal maturation the HI increases to a maximum value, HImax. Similarly, QI increases to a maximum value, QImax. This increase in HI and QI is related to the formation of an additional generation potential in the coal structure. The decline in QI with further maturation is indicating onset of initial oil expulsion, which precedes efficient expulsion. Liquid petroleum generation from humic coals is thus a complex, three-phase process: (i) onset of petroleum generation, (ii) petroleum build-up in the coal, and (iii) initial oil expulsion followed by efficient oil expulsion (corresponding to the effective oil window). Efficient oil expulsion is indicated by a decline in the Bitumen Index (BI) when plotted against vitrinite reflectance or Tmax. This means that in humic coals the vitrinite reflectance or Tmax values at which onset of petroleum generation occurs cannot be used to establish the start of the effective oil window. The start of the effective oil window occurs within the vitrinite reflectance range 0.85–1.05%Ro or Tmax range 440–455 °C and the oil window extends to 1.5–2.0%Ro or 470–510 °C. For general use, an effective oil window is proposed to occur from 0.85 to 1.7%Ro or from 440 to 490 °C. Specific ranges for HImax and the effective oil window can be defined for Cenozoic, Jurassic, Permian, and Carboniferous coals. Cenozoic coals reach the highest HImax values (220–370 mg HC/g TOC), and for the most oil-prone Cenozoic coals the effective oil window may possibly range from 0.65 to 2.0%Ro or 430 to 510 °C. In contrast, the most oil-prone Jurassic, Permian and Carboniferous coals reach the expulsion threshold at a vitrinite reflectance of 0.85–0.9%Ro or Tmax of 440–445 °C. 相似文献
13.
The Gondwana sediments comprising fine-grained shales, carbonaceous shales, sandstones and the coal horizon in borecore RT-4
(approximately 547.00m thick) from Tamra block, Raniganj Coalfield, Damodar Basin, are analyzed palynologically. Based on
the distribution pattern of marker palynotaxa, two assemblage zones are identified. In the Barren Measures Formation, dominance
of enveloping monosaccate (Densipollenites) along with striate bisaccate (Striatopodocarpites, Faunipollenites) pollen taxa, and the FAD’s of Kamthisaccites and Arcuatipollenites observed at 30.75, have equated this strata (30.75–227.80 m thick) with the Raniganj Formation of Late Permian in age. Downwards
in the Barakar Formation, between 423.80–577.70 m depths, an abundance of non-striate (Scheuringipollenites) and striate (Faunipollenites and Striatopodocarpites) bisaccate pollen taxa is observed, that dates late Early Permian in age. 相似文献
14.
TAO Mingxin LI Jing LI Xiaobin MA Yuzhen LI Zhongping WANG Zuodong GAO Zhongliang ZHANG Xiaojun WANG Yanlong 《《地质学报》英文版》2012,86(1):199-208
According to the adsorption-desorption characteristics of coalbed gas and analysis of various experimental data, this paper proposes that the generation of secondary biogenic gas (SBG) and its mixing of with the residual thermogenic gas at an early stage inevitably lead to secondary changes of the thermogenic gas and various geochemical additive effects. Experimental results also show that the fractionation of the carbon isotope of methane of coal core desorption gas changes very little; the δ13C1 value of the mixed gas of biogenic and thermogenic gases is between the δ13C1 values of the two “original” gases, and the value is determined by the carbon isotopic compositions and mixing proportions of the two “original” methanes. Therefore this paper proposes that the study on the secondary changes of the thermogenic gas and various additive effects is a new effective way to study and identify SBG. Herein, a systematic example of research on the coalbed gas (Huainan coalbed gas) is further conducted, revealing a series of secondary changes and additive effects, the main characteristics and markers of which are: (1) the contents of CO2 and heavy-hydrocarbons decrease significantly; (2) the content of CH4 increases and the gas becomes drier; (3) the δ13C and δD values of methane decrease significantly and tend to have biogenetic characteristics; and (4) the values of δ13C2 and δ13CCO2 grow higher. These isotopic values also change with the degradation degrees by microbes and mixing proportions of the two kinds of gases in different locations. There exists a negative correlation between the δ13C1 vs δ13CCO2 values. The △δ13CC2–C1 values obviously become higher. The distributions of the △δ13CCO2–C1 values are within certain limits and show regularity. There exist a positive correlation between the N2 versus Ar contents, and a negative correlation between the N2 versus CH4 contents, indicating the down forward infiltration of the surface water containing air. These are important markers of the generation and existence of SBG. 相似文献
15.
Paul C. Hackley Edgar H. Guevara Tucker F. Hentz Robert W. Hook 《International Journal of Coal Geology》2009,77(3-4):294-309
Thermal maturity was determined for about 120 core, cuttings, and outcrop samples to investigate the potential for coalbed gas resources in Pennsylvanian strata of north-central Texas. Shallow (< 600 m; 2000 ft) coal and carbonaceous shale cuttings samples from the Middle-Upper Pennsylvanian Strawn, Canyon, and Cisco Groups in Archer and Young Counties on the Eastern Shelf of the Midland basin (northwest and downdip from the outcrop) yielded mean random vitrinite reflectance (Ro) values between about 0.4 and 0.8%. This range of Ro values indicates rank from subbituminous C to high volatile A bituminous in the shallow subsurface, which may be sufficient for early thermogenic gas generation. Near-surface (< 100 m; 300 ft) core and outcrop samples of coal from areas of historical underground coal mining in the region yielded similar Ro values of 0.5 to 0.8%. Carbonaceous shale core samples of Lower Pennsylvanian strata (lower Atoka Group) from two deeper wells (samples from ~ 1650 m; 5400 ft) in Jack and western Wise Counties in the western part of the Fort Worth basin yielded higher Ro values of about 1.0%. Pyrolysis and petrographic data for the lower Atoka samples indicate mixed Type II/Type III organic matter, suggesting generated hydrocarbons may be both gas- and oil-prone. In all other samples, organic material is dominated by Type III organic matter (vitrinite), indicating that generated hydrocarbons should be gas-prone. Individual coal beds are thin at outcrop (< 1 m; 3.3 ft), laterally discontinuous, and moderately high in ash yield and sulfur content. A possible analog for coalbed gas potential in the Pennsylvanian section of north-central Texas occurs on the northeast Oklahoma shelf and in the Cherokee basin of southeastern Kansas, where contemporaneous gas-producing coal beds are similar in thickness, quality, and rank. 相似文献
16.
Thermally altered pods of coal of very high rank have been observed in a high-volatile-bituminous coal seam in the eastern side of Eagle Mountain, Elk Valley Coalfield, British Columbia. Rank changes have been measured over a strike distance of 7.5 m from 1.24% to 7.1% Ro max, corresponding to a rank gradient of 0.78% Rom−1.Petrologically, unaltered to extremely altered vitrinite showing nongranular (basic) anisotropy, mosaic-textured liptinite and pyrolytic carbon are the most abundant components. The limited presence of mosaic on vitrinite is an indication that the coal seam may have been weathered prior to being heat-affected.Evidence points to localized temperatures as high as 1,000°C, which could have been caused by a lightning strike. The eastern side of Eagle Mountain has experienced higher temperatures than the western side, and it appears that the heat ‘front’ and zone of alteration have an irregular pattern, pointing to saturation of parts of the coal seam by water.Four types of pyrolytic carbon having distinct morphology, anisotrophy and optical path with increasing temperature were observed. Reflectance of pyrolytic carbon falls within the zone of heat-affected coals, whereas the optical path of heat-affected Seam 15 samples is different from that of fresh coal with increasing rank.Finally, the reflectance of vitrinite in heat-affected coal is higher than the reflectance of vitrinite in carbonaceous shale in the Seam 15 section. 相似文献
17.
Role of coal type and rank on methane sorption characteristics of Bowen Basin, Australia coals 总被引：5，自引：0，他引：5
The effect of coal composition, particularly the organic fraction, upon gas sorption has been investigated for Bowen Basin and Sydney Basin, Australia coals. Maceral composition influences on gas retention and release were investigated using isorank pairs of hand-picked bright and dull coal in the rank range of high volatile bituminous (0.78% Ro max) to anthracite (3.01% Ro max). Adsorption isotherm results of dry coals indicated that Langmuir volume (VL) for bright and dull coal types followed discrete, second-order polynomial trends with increasing rank. Bright coals had a minimum VL at 1.72% Ro max and dull coals had a minimum VL at 1.17% Ro max. At low rank, VL was greater in bright coal by about 10 cm3/g, but as rank increased, the bright and dull trends converged and crossed at 1.65% Ro max. At ranks higher than 1.65% Ro max, both bright and dull coals followed similar trends. These competing trends mean that the importance of maceral composition on VL varies according to rank. In high volatile bituminous coals, increases in vitrinite content are associated with increases in adsorption capacity. At ranks higher than medium to low volatile bituminous, changes in maceral composition may exert relatively little influence on adsorption capacity. The Langmuir pressure (PL) showed a strong relationship of decreasing PL with increasing rank, which was not related to coal type. It is suggested that the observed trend is related to a decrease in the heterogeneity of the pore surfaces, and subsequent increased coverage by the adsorbate, as coal rank increases. Desorption rate studies on crushed samples show that dull coals desorb more rapidly than bright coals and that desorption rate is also a function of rank. Coals of lower rank have higher effective diffusivities. Mineral matter was found to have no influence on desorption rate of these finely crushed samples. The evolution of the coal pore structure with changing rank is implicated in diffusion rate differences. 相似文献
18.
针对黔西北（贵州毕节）可乐向斜中段晚二叠世含煤地层具有含煤层数多、主力煤层埋藏较深的特点,结合该区探井钻遇致密砂岩气层的实际情况,从沉积环境、储层厚度、源储配置及含气性等方面评价了该区煤层气与致密砂岩气"两气"共探的勘探潜力。研究表明:可乐向斜下煤组和中煤组分别沉积于龙潭早期和晚期,这两个时期地层主要处于曲流河、河控三角洲平原等沉积相带,有利于煤岩与致密砂岩储层的形成;龙潭组中煤组煤层和致密砂岩层分布较稳定,累积厚度分别在16 m和20 m以上;煤系中煤岩、泥岩、砂岩互层叠置出现,具备良好的源储配置关系,可形成多套"生储盖组合";根据X1井气测录井和测井结果,在煤层和致密砂岩层均显示全烃值异常,煤层段异常值最大可达78.35%,钻遇的两层致密砂岩层含气饱和度分别为39.97%和12.79%,说明煤系中有"两气"共存的情况。 相似文献
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通过数理统计前人公开发表的国内外21个盆地或地区的324组煤型气地化数据, 分析不同成因类型煤型气地层分布和稳定碳、氢同位素组成及空间分布特征, 提出多个煤型气成因类型判识图版, 并以实例论证这些图版的可行性.研究结果表明: 与煤层相关的生物成因气不同于常规生物气, 最显著区别在于前者δ13C(CH4)上限值低, 即生物成因气δ13C(CH4)＜-60‰, 热成因气δ13C(CH4)＞-40‰, 混合成因气δ13C(CH4)介于二者之间.随着有机质演化程度增强, 从生物成因气至热成因气, δ13C(CH4)、δ13C(CO2-CH4)、δ13C(C2H6-CH4)及CH4/(C2H6+C3H8)具有变重趋势且相关性明显, δ13C(CH4)与δ13C(CO2-CH4)、δ13C(CH4)与δ13C(C2H6-CH4)及δ13C(CH4)与CH4/(C2H6+C3H8)是划分煤型气成因类型最可靠的图版. 相似文献