页岩气储层非均质性研究——以四川盆地下寒武统筇竹寺组为例

在详细调研国内外页岩气储层非均质性研究的基础上,以四川盆地下寒武统筇竹寺组为例,通过平面、层内和微观3个方面分析了泥页岩非均质性特征。平面非均质性主要受区域沉积特征和泥页岩有机地球化学特征控制,盆地中西部主要发育泥质砂岩和砂质泥岩,总有机碳含量TOC和有机质成熟度相对较低;东北部泥质灰岩发育,TOC和有机质成熟度较高;南部以碳质泥页岩为主,TOC和有机质成熟度最高(镜质体反射率Ro可达4.0%)。连井剖面和单井泥岩层矿物特征分析表明,层内非均质性较强,主要表现为横向上地层总厚度、泥页岩单层厚度、泥页岩发育层数、夹层特征和顶—底板岩性沿剖面变化快,纵向上矿物成分和岩石脆性度差异明显。微观非均质性主要受孔隙类型和基质微裂缝影响,黏土层间孔隙和有机质孔隙发育,基质微裂缝对沟通孔隙起主要作用。综合分析认为,四川盆地下寒武统筇竹寺组页岩气储层非均质性特征明显,对页岩气井产能和页岩气采收率有重要影响。     

四川盆地焦石坝地区龙马溪组页岩层序及页岩气“甜点”地震预测

我国页岩气勘探开发在四川盆地焦石坝地区龙马溪组已经取得重大突破,针对性的页岩气"甜点"地球物理技术亟待研究和探索。沉积相是进行页岩气甜点预测和描述的重要基础和依据。应用层序地层学理论,建立了页岩层段的三级层序地层格架,认清了深水陆棚页岩沉积相的展布规律,目的层五峰组及龙马溪组富碳高硅和高碳高硅泥页岩主要分布在三级层序的海侵体系域。在此基础上,探索了层序地层格架控制下的页岩气"甜点"的地球物理识别和预测方法。研究认为,页岩气地球物理识别与预测技术在含气页岩有机碳含量(TOC)、裂缝和脆性等方面具有较大的优势,能为页岩气水平井分段压裂工程和水平井轨迹设计提供有力的技术支持。     

织锦巴非蛤斧足颜色与总类胡萝卜素含量相关分析

斧足是织锦巴非蛤重要的食用部位。本研究检测了94个织锦巴非蛤斧足的总类胡萝卜素含量(TCC)和3个颜色指标L*(明暗度)、a*(红绿值)、b*(黄蓝值),发现织锦巴非蛤斧足总类胡萝卜素含量和颜色指标在不同个体之间存在较大差异。相关性分析表明,织锦巴非蛤斧足的总类胡萝卜素含量与颜色指标L*、a*、b*之间相关极显著(P0.01),相关系数分别为:–0.546、0.569、0.449。本研究表明,斧足颜色越深,其类胡萝卜素含量也越高可能是一个普遍规律,这对我们接下来选育高类胡萝卜素含量贝类提供了一种直观的参考指标。     

胶州湾水体悬浮物浓度遥感反演模式优化研究

为了及时、准确的了解胶州湾水域总悬浮物情况,采用2001—2015年水面实测数据,选取HJ-1、MERIS、LandsatTM/ETM+三个不同卫星数据,通过ENVI软件分析计算TM/ETM数据的多波段组合与总悬浮物浓度之间的相关关系,选取相关系数最大者分别构建多元函数回归模型,对胶州湾总悬浮物浓度进行了遥感定量反演研究。结果表明,估算因子三波段模型432算法与悬浮物浓度的相关性最好(R20.8),反演精度较高,以此建立了悬浮物浓度三波段半分析+生物光学遥感反演模型,检验值R~2均高于0.85,并通过F检验法和均方根误差(RMSE)分析,证明误差的敏感性差,该模型相关系数及稳定性好。因此,三波段模型在这三种反演模型中精度最好。     

光照强度对番红砗磲外套膜颜色变化的影响

以蓝色、棕黄色和绿色三种不同外套膜颜色的番红砗磲(Tridacna crocea)为实验对象,设置5000 lx、10000 lx和15000 lx三组光照强度,探究了番红砗磲外套膜颜色变化与光照强度的相关性。结果表明:(1)在不同光照强度下,蓝色个体外套膜颜色加深,棕黄色个体颜色变化不大,而绿色个体外套膜颜色变浅。(2)蓝色个体在光照刺激2周后外套膜颜色即出现显著变化,0~2周色差为13.81~21.59;在不同光照强度刺激下,棕黄色和绿色个体的外套膜颜色的色差随时间延长而逐渐增强,4~6周外套膜颜色色差最大。(3)番红砗磲原外套膜颜色类别对其外套膜颜色红绿特征数值(a)和黄蓝特征数值(b)影响显著(P<0.05);光照强度对番红砗磲外套膜颜色黄蓝特征数值(b)影响显著(P<0.05);光照强度和番红砗磲原外套膜颜色类别的交互作用对红绿特征数值(a)的影响显著。上述结果可为定向培育外套膜颜色鲜艳的番红砗磲以及解析砗磲环境适应机制提供参考。     

基于回归分析的滨海湿地草本植物生物量估算方法研究

为了研究利用滨海湿地草本植物的形态指标来估算植物生物量,根据黄河三角洲互花米草(Spartina alterniflora)的调查数据,运用Pearson相关系数和回归分析法,分析了互花米草的形态指标高度、密度、茎直径与地上生物量、地下生物量、总生物量的相关性,构建了回归模型。结果表明:地上生物量和总生物量均与植株高度、密度、茎直径在0.01水平上显著相关,地下生物量与植株密度在0.01水平上显著相关。将相关性显著的生物量和相应的形态指标进行回归分析发现,其拟合优度较好,其中,拟合优度最优的回归模型分别是地上生物量与高度的“J”型增长曲线模型(拟合优度为R²=0.904)、总生物量与密度的一元线性回归模型(拟合优度为R²=0.659)。经过应用精度验证,上述两个模型评价结果均较好,估算值与实测值绝对误差范围为0.01~0.17 kg/m²,相对误差范围为0.71%~12.02%,符合实际估算应用需求。研究结果说明互花米草的生物量可以通过与其相关性较高的形态指标进行回归估算获得。     

基于色度平面的自适应颜色聚类

本文的目标是寻找具有更高灵活性和自适应性的颜色聚类方法。在分析了多种颜色聚类方法的基础上 ,提出了 2种无监督的二维色度平面颜色聚类方法 :基于密度的三角化方法和遗传算法优化方法 ,并通过实验对 2种方法进行了比对分析。结果表明 ,基于密度的三角化方法具有很好的边界拟合效果 ,而遗传算法优化对于复杂的数据集和解决干扰噪声有更好的效果。     

大通湖中华绒螯蟹(Eriocheir sinensis)自然生产潜力估算模型探讨

人放天养的中华绒螯蟹(Eriocheir sinensis)质量好、个体大、耐运输、肉质鲜美,是优质高档蟹的代表,但产量严重不足。建立一套湖泊中华绒螯蟹自然生产潜力估算的模型来估算湖泊中华绒螯蟹自然生产潜力,确定放养量,以达到湖泊中华绒螯蟹稳产已迫在眉睫。本文根据近20年来作者对湖泊中华绒螯蟹放养的经验,结合灰估理论,提出蟹自然生产潜力:W=[B1K1C1/R1+B2K2C2/R2]·(B1+B2)2/B12+B2和蟹种放养量:W0=P0[B1K1C1/R1+B2K2C2/R2]·U/P估算模型,并与生产实践进行求证。其结果与生产实践存在较好的一致性。其估算结果可作为指导湖泊中华绒螯蟹生产的依据。     

黄海、东海水体总吸收系数光谱特性及其统计反演模式研究

利用现场实测的表观光学量和固有光学量数据,得到了我国黄海、东海近岸二类水体多个波段的总吸收系数的统计反演模式。此反演模式采用412/555、490/555两个波段遥感反射比比值的二项式,得到波长412、440、488、510、532、555nm处的总吸收系数,其反演值和实测值的平均相对误差不大于25.8%,相关系数R2达到了0.75到0.85。水体总吸收系数几种统计模型的误差敏感性分析表明,反演模式对±5%的遥感反射比输入误差导致结果增加误差最大为24.0%,因此反演模式是可用的。同时给出了412、488、510、532、555nm各波段的总吸收系数同波段440nm的总吸收系数之间的关系。结果表明,在400—600nm波段范围内,每一个波段的总吸收系数与440nm波段的总吸收系数的相关性均较高,相关系数R2都超过了0.99。通过对拟合直线的斜率与波长进行回归,得到斜率和波长的关系,其相关系数R2为0.99,这样利用本文中建立的各波段总吸收系数关系模型,可以从一个已知波段的总吸收系数反演出任何另外一个波段的总吸收系数,这就在水色反演与应用中大大减少了未知因子的个数。     

构造生烃理论及其在页岩气上的应用

生烃是地层有机质生成油气的化学平衡。由于油气的密度低于干酪根,它是典型的体积增大化学反应。与实验室开放系统不同,地层有机质生烃反应能等于活化能加排烃能。成熟阶段的地层比较致密,排烃能较大,与开放系统相比,形成了欠生烃。构造运动形成裂隙网,大大降低地层排烃能,使欠生烃的有机质短时间集中生烃,笔者称之为构造生烃。成熟地层通常较致密,排烃能较高,较多欠生烃有机质成为页岩气的物质基础。致密地层在过成熟条件下还有大量欠生烃有机质。经典生烃理论认为Ro大于2.0就基本不生烃,而许多Ro达到3.0,个别甚至4.0的页岩气发现,证明欠生烃的存在。分子越小,排烃能越低,相对致密地层生气的反应能通常最低,更多的有机质形成了页岩气,页岩气资源潜力巨大。页岩气的开采速度比地层自然排烃速度高出多个数量级,天然气排出最快的,最有利于生成天然气的化学平衡。勘探开发实践表明页岩含气量与其TOC成正比,笔者认为这正好预示着页岩中存在游离气、吸附气和有机质的化学平衡。游离气压降低,吸附气就会解吸附;吸附气解吸附,有机质就会生烃。有些过成熟岩石存在未—低成熟度Tmax值。这样低的Tmax值预示着,有机质能够在地层被压裂后随着排烃能的降低而满足反应条件,而成为潜在资源。页岩气的开采与普通气层相比更复杂、更漫长、更巨大。     

Experimental investigation of thermal maturation on shale reservoir properties from hydrous pyrolysis of Chang 7 shale,Ordos Basin

Thermal maturity has a significant impact on hydrocarbon generation and the storage capacity within shales, but explicit and quantitative characterization of that impact on continental shales is scarce. To better understand how thermal maturation affects the organic and inorganic changes of the continental shale reservoirs, hydrous pyrolysis was performed to simulate the maturation process. TOC, Rock-Eval and adsorption isotherms tests were used to obtain various geochemical parameters of the shale solid residues. The results indicate that with pyrolysis temperature increasing from ambient temperature to 550 °C, the vitrinite reflectance increases from 0.5% to 2.5% Ro and the TOC (total organic carbon) loss weight reaches 25%. Regarding porosity, the fraction of micro-to meso-pores in the shale increases with an increase in the pyrolysis temperature, whereas the macro-pores do not change significantly. The total amount of gas adsorption does not necessarily increase as the TOC is consumed, but the gas adsorption capacity per unit of TOC increases with increasing thermal maturity. Our finding provides theoretical modelling for identifying shale gas development prospective zones according to thermal maturity mapping and for predicting quantitatively the geochemical and inorganic changes that occur with thermal evolution.     

Sedimentary and residual gas geochemical characteristics of the Lower Cambrian organic-rich shales in Southeastern Chongqing,China

To study the sedimentary environment of the Lower Cambrian organic-rich shales and isotopic geochemical characteristics of the residual shale gas, 20 black shale samples from the Niutitang Formation were collected from the Youyang section, located in southeastern Chongqing, China. A combination of geochemical, mineralogical, and trace element studies has been performed on the shale samples from the Lower Cambrian Niutitang Formation, and the results were used to determine the paleoceanic sedimentary environment of this organic-rich shale. The relationships between total organic carbon (TOC) and total sulfur (TS) content, carbon isotope value (δ¹³C_org), trace element enrichment, and mineral composition suggest that the high-TOC Niutitang shale was deposited in an anoxic environment and that the organic matter was well preserved after burial. Stable carbon isotopes and biomarkers both indicate that the organic matter in the Niutitang black shales was mainly derived from both lower aquatic organisms and algaes and belong to type I kerogen. The oil-prone Niutitang black shales have limited residual hydrocarbons, with low values of S₂, I_H, and bitumen A. The carbon isotopic distribution of the residual gas indicate that the shale gas stored in the Niutitang black shale was mostly generated from the cracking of residual bitumen and wet gas during a stage of significantly high maturity. One of the more significant observations in this work involves the carbon isotope compositions of the residual gas (C₁, C₂, and C₃) released by rock crushing. A conventional δ¹³C₁–δ¹³C₂ trend was observed, and most δ¹³C₂ values of the residual gases are heavier than those of the organic matter (OM) in the corresponding samples, indicating the splitting of ethane bonds and the release of smaller molecules, leading to ¹³C enrichment in the residual ethane.     

Black shales in Ukraine – A review

As a result of a long-lasting and complex geological history, organic-matter-rich fine-grained rocks (black shales) with widely varying ages can be found on Ukrainian territory. Several of them are proven hydrocarbon source rocks and may hold a significant shale gas potential.Thick Silurian black shales accumulated along the western margin of the East European Craton in a foreland-type basin. By analogy with coeval organic-matter-rich rocks in Poland, high TOC contents and gas window maturity can be expected. However, to date information on organic richness is largely missing and maturity patterns remain to be refined.Visean black shales with TOC contents as high as 8% and a Type III-II kerogen accumulated along the axis of the Dniepr-Donets rift basin (DDB). They are the likely source for conventional oil and gas. Oil-prone Serpukhovian black shales accumulated in the shallow northwestern part of the DDB. Similar black shales probably may be present in the Lviv-Volyn Basin (western Ukraine).Middle Jurassic black shales up to 500 m thick occur beneath the Carpathian Foredeep. They are the likely source for some heavy oil deposits. TOC contents up to 12% (Type II) have been recorded, but additional investigations are needed to study the vertical and lateral variability of organic matter richness and maturity.Lower Cretaceous black shales with a Type III(-II) kerogen (TOC > 2%) are widespread at the base of the Carpathian flysch nappes, but Oligocene black shales (Menilite Fm.) rich in organic matter (4–8% TOC) and containing a Type II kerogen are the main source rock for oil in the Carpathians. Their thermal maturity increases from the external to the internal nappes.Oligocene black shales are also present in Crimea (Maykop Fm.). These rocks typically contain high TOC contents, but data from Ukraine are missing.     

南日群岛东部海域岩芯沉积物有机碳含量和δ13CTOC值的变化特征及古气候环境意义

2008年在南日群岛东部海域用钻机采集长度为1 004 cm的岩芯样品,测试沉积物中总有机碳（TOC）含量、稳定碳同位素比值（δ13CTOC）、碳氮比值（C/N）、碳酸盐含量以及14C数据,分析其垂直剖面上的变化特征,阐明其沉积环境和古气候的指示意义.沉积物TOC含量变化范围为0.44%～0.74%,垂直剖面上总体显示出末次冰期和全新世中期TOC含量较高,全新世早期相对稳定,而全新世中后期TOC波动范围明显增大.C/N值在5.3～14.9之间变化,平均值为8.1;δ13CTOC值范围为-23.07‰～-21.04‰,表明沉积物中的有机质以海洋自生为主,同时混有部分陆源有机质.碳酸盐含量在3.3%～10.9%之间.TOC含量、C/N比值、δ13CTOC值在岩芯垂直剖面上具有很好的相关性.14C测年数据以及各要素测值在垂直剖面上的变化特征表明：自11 250 aBP以来该海域附近古气候有可能经历了以下4个演化阶段：①11 500～9 000 aBP期间气候寒冷、海平面下降,采样点可能为浅水区或潮间带;②9 000～8 000 aBP期间为升温期,气候由寒冷转向温暖;③8 000～4 300 aBP期间,为相对稳定的暖湿期,在后期气候出现小幅的波动;④4 300 aBP至今,气候进入明显的周期性波动期,暖湿和干冷气候多次交替变化;4 300～3 000 aBP期间为相对寒冷的时期;3 000～1 800 aBP期间为较稳定温暖期,1 800～1 000 aBP期间气温快速降低,标志着研究区进入一个新的寒冷阶段,但是自1 000 aBP以来,气候又再次出现转暖的趋势.     

Comprehensive polynomial simulation and prediction for Langmuir volume and Langmuir pressure of shale gas adsorption using multiple factors

In this study, 32 experimental measurements on the isothermal adsorption of methane for 18 shale samples from China's three largest continental oil basins—Songliao, Bohai Bay, and Ordos basins—were used to construct comprehensive polynomial simulation and prediction models for Langmuir volume and Langmuir pressure. The models were based on shale properties (total organic carbon (TOC) content, amount of residual hydrocarbon S₁, and mineral composition of rocks) and adsorption condition (temperature) using a weighted sum of multiple variables. The influences of various factors were quantitatively characterized, and the prediction accuracy was verified. Langmuir volume is mainly affected by temperature, shale TOC content, amount of residual hydrocarbon, and clay mineral content; Langmuir pressure is mainly affected by clay, carbonate, feldspar and illite content (because shale pore size can be affected by shale mineral composition). Based on the resource potential and the producibility of shale gas, the area suitable for shale gas exploration and development should have high abundance of organic matter (TOC and residual hydrocarbon S₁), low clay mineral content and feldspar content, high conversion rate of montmorillonite to illite (strong diagenesis), and high carbonate content. The comprehensive polynomial prediction model can effectively simulate and predict Langmuir volume and Langmuir pressure, thereby reducing the amount of work necessary for evaluation of shale gas resource potential and economic feasibility.     

Geological models of gas in place of the Longmaxi shale in Southeast Chongqing,South China

Gas-in-place (GIP) is one of the primary controlling factors in shale gas production, but studies examining GIP have been lacking for the Lower Silurian Longmaxi shale in South China. In the present study, a suite of Longmaxi shale samples was collected from an exploratory well in Southeast Chongqing, South China, and the adsorption parameters were fitted using a supercritical Dubinin-Radushkevich (SDR) model based on the high-pressure methane adsorption experiment data for the samples. The results show that the adsorbed phase density and the adsorbed gas capacity of the samples have a positive correlation with the content of total organic carbon (TOC) but a negative correlation with temperature. Combined with the geological characteristics of the Longmaxi shale in Southeast Chongqing, GIP models were constructed under three different fluid pressure conditions. The absolute adsorbed amount of the samples increases and later decreases with increasing depth with a maximum corresponding to depths between 800 and 1200 m. The fluid pressure coefficient has no obvious effect on the absolute adsorbed amount when burial depth is over 2000 m but controls the free gas content. Overpressure primarily increases the free gas content and thus increases the total gas content. The free gas content of the Longmaxi shale in the Pengshui Block is reduced to 47%–58% of that in the Fuling Block, which is the main reason for its low gas production. Further exploration of the Longmaxi Formation should be expanded to deeper burial shales in the eastern area of Southeast Chongqing.     

LIC color texture enhancement algorithm for ocean vector field data based on HSV color mapping and cumulative distribution function

Texture-based visualization method is a common method in the visualization of vector field data. Aiming at adding color mapping to the texture of ocean vector field and solving the ambiguity of vector direction in texture image, a new color texture enhancement algorithm based on the Line Integral Convolution (LIC) for the vector field data is proposed, which combines the HSV color mapping and cumulative distribution function calculation of vector field data. This algorithm can be summarized as follows: firstly, the vector field data is convoluted twice by line integration to get the gray texture image. Secondly, the method of mapping vector data to each component of the HSV color space is established. And then, the vector field data is mapped into HSV color space and converted from HSV to RGB values to get the color image. Thirdly, the cumulative distribution function of the RGB color components of the gray texture image and the color image is constructed to enhance the gray texture and RGB color values. Finally, both the gray texture image and the color image are fused to get the color texture. The experimental results show that the proposed LIC color texture enhancement algorithm is capable of generating a better display of vector field data. Furthermore, the ambiguity of vector direction in the texture images is solved and the direction information of the vector field is expressed more accurately.     

南海北部柱状沉积物中黄铁矿的分布特征和形貌研究

对南海北部陆坡柱状沉积物样品总有机碳、总硫含量,以及其中的自生黄铁矿形貌、含量进行分析．结果显示,沉积物中黄铁矿（FeS2）、总有机碳（TOC）、总硫（TS）的质量分数分别为0～0,71％、0．37％～1．18％、0．04％～0．81％;黄铁矿和总有机碳、总硫的含量随深度加深逐渐增大,达到峰值后不断减少,三者的分布趋势基本一致;扫描电镜下观察到黄铁矿主要以莓球状集合体和八面体微晶形貌产出,局部层位亦发现管状、生物内膜状和立方体状黄铁矿晶体．表明该区浅表层环境为缺氧环境,硫化物主要以黄铁矿形式产出,其成因与有机质的厌氧氧化作用有关,而甲烷的厌氧氧化作用也可能促使自生黄铁矿的加速形成．莓球状黄铁矿占主导亦指示一种强还原性的缺氧微环境．黄铁矿富集的缺氧环境与下伏地层中天然气水合物分解释放的甲烷有关,为天然气水合物在该区的勘探提供一定的科荤依据．     

Qualitative and quantitative characterization of a transitional shale reservoir: A case study from the Upper Carboniferous Taiyuan shale in the eastern uplift of Liaohe Depression,China

The paper takes the Upper Carboniferous Taiyuan shale in eastern uplift of Liaohe depression as an example to qualitatively and quantitatively characterize the transitional (coal-associated coastal swamp) shale reservoir. Focused Ion Beam Scanning Electron Microscope (FIB-SEM), nano-CT, helium pycnometry, high-pressure mercury intrusion and low-pressure gas (N₂ & CO₂) adsorption for eight shale samples were taken to investigate the pore structures. Four types of pores, i.e., organic matter (OM) pores, interparticle (InterP) pores, intraparticle (IntraP) pores and micro-fractures are identified in the shale reservoir. Among them, intraP pores and micro-fractures are the major pore types. Slit-shaped pores are the major shape in the pore system, and the connectivity of the pore-throat system is interpreted to be moderate, which is subordinate to marine shale. The porosity from three dimension (3D) reconstruction of SEM images is lower than the porosity of helium pycnometry, while the porosity trend of the above two methods is the same. Combination of mercury intrusion and gas absorption reveals that nanometer-scale pores provide the main storage space, accounting for 87.16% of the pore volume and 99.85% of the surface area. Micropores contribute 34.74% of the total pore volume and 74.92% of the total pore surface area; and mesopores account for 48.27% of the total pore volume and 24.93% of the total pore surface area; and macropores contribute 16.99% of the total pore volume and 0.15% of the total pore surface area. Pores with a diameter of less than 10 nm contribute the most to the pore volume and the surface area, accounting for 70.29% and 97.70%, respectively. Based on single factor analysis, clay minerals are positively related to the volume and surface area of micropores, mesopores and macropores, which finally control the free gas in pores and adsorbed gas content on surface area. Unlike marine shale, TOC contributes little to the development of micropores. Brittle minerals inhibit pore development of Taiyuan shale, which proves the influence of clay minerals in the pore system.