Hydrocarbon Generation Kinetic Characteristics from Different Types of Organic Matter

In order to contrast the hydrocarbon generation kinetic characteristics from different types of organic matter（OM）,18 samples from different basins were pyrolyzed using Rock-Eval-Ⅱapparatus under the open system.From the experimental results,the curve of hydrocarbon generation rate vs.temperature can be easily obtained,which usually can be used to optimize kinetic parameters （A,E,F）of the hydrocarbon generation model.In this paper,the parallel first-order reaction with a single frequency factor model is selected to describe the hydrocarbon generation kinetic characteristics. The hydrocarbon generation kinetic parameters reveal that the types of compound structures and chemical bonds of the lacustrine fades typeⅠOM are relatively homogeneous,with one dominating activation energy.The types of chemical bonds of the lacustrine facies typeⅡ2 OM and the terrestrial facies typeⅢOM are relative complex,with a broad activation energy distribution,and the reaction fraction of the preponderant activation energy drops with the decrease of hydrogen index.The impact of the activation energy distribution spaces on the geological extrapolation of kinetic parameters is also investigated.The results show that it has little effect on the hydrocarbon transformation ratio（TR）and therefore,the parallel first-order reaction model with proper number of activation energies can be better used to describe the hydrocarbon generation process.The geological extrapolation results of 18 samples of kinetic parameters show that the distribution range of the hydrocarbon generation rate of the typeⅠOM is relatively narrow and the hydrocarbon generation curve is smooth.In comparison,the distribution range of the hydrocarbon generation for typeⅢand typeⅡ2-ⅢOM are quite wide,and the hydrocarbon generation curves have fluctuation phenomena.The distribution range of the hydrocarbon generation rate and the fluctuation phenomena are related to the kinetic parameters of OM;the narrower the activation energy distribution,the narrower the hydrocarbon generation rate distribution,and the smoother the hydrocarbon generation curve,and vice versa.

Simulation experiment on hydrocarbon generating potential of various source rocks on the northern margin of the Qaidam Basin,Qinghai,China

The northern margin of the Qaidam Basin is one of the main oil-gas exploration areas in western China,where source rocks are composed mostly of Middle and Lower Jurassic dark mud shale,carbargillite and coal. A large number of subsurface and outcrop samples differing in lithology with different types of organic matter were selected for resource evaluation,research and calculation. And among them,13 samples were used for simulation experiment on hydrocarbon generating potential of various source rocks. At first,two kinds of heating modes were compared through simulation experiment,including single temperature-step heating and continual heating. Perhaps,the process of hydrocarbon generation and expulsion occurred naturally between a close system and an open system. In addition,the first heating mode was convenient,and all its reaction products were involved in the whole thermal evolution,and the final simulation experimental results were basically in consistency with the natural evolution trend. Therefore,the first heating mode was adopted and the hydrocarbon yield of every sample was worked out. Accord-ing to the type and lithology of organic matter and the hydrocarbon yield of samples for simulation experiment,hy-drocarbon generation and expulsion mode with three kinds of lithology and five types of source rock has been estab-lished to provide the basis for hydrocarbon generation evaluation,research and resource calculation.

Assessment of recoverable oil and gas resources by in-situ conversion of shale——Case study of extracting the Chang 7_(3) shale in the Ordos Basin

The purpose of this study is to investigate the entire evolution process of shales with various total organic contents(TOC)in order to build models for quantitative evaluation of oil and gas yields and establish methods for assessing recoverable oil and gas resources from in-situ conversion of organic matters in shale.Thermal simulation experiments under in-situ conversion conditions were conducted on Chang 7_(3) shales from the Ordos Basin in a semi-open system with large capacity.The results showed that TOC and R_(o) were the key factors affecting the in-situ transformation potential of shale.The remaining oil and gas yields increased linearly with TOC but inconsistently with R_(o).R_(o) ranged 0.75%—1.25%and 1.05%—2.3%,respectively,corresponding to the main oil generation stage and gas generation stage of shale in-situ transformation.Thus a model to evaluate the remaining oil/gas yield with TOC and R_(o) was obtained.The TOC of shale suitable for in-situ conversion should be greater than 6%,whereas its R_(o) should be less than 1.0%.Shales with 0.75%(R_(o))could obtain the best economic benefit.The results provided a theoretical basis and evaluation methodology for predicting the hydrocarbon resources from in-situ conversion of shale and for the identification of the optimum“sweet spots”.The assessment of the Chang 7_(3) shale in the Ordos Basin indicated that the recoverable oil and gas resources from in-situ conversion of organic matters in shale are substantial,with oil and gas resources reaching approximately 450×10^(8) t and 30×10^(12)m^(3),respectively,from an area of 4.27×10^(4) km^(2).

Modeling of the whole hydrocarbon-generating process of sapropelic source rock

Based on experimental data from hydrocarbon generation with a semi-open system, hydrocarbon generation kinetics modeling in gold tube of closed system, high temperature pyrolysis chromatography mass spectrometry experiment with open system and geological data, the characteristics of whole hydrocarbon-generating process, hydrocarbon expulsion efficiency and retained hydrocarbon quantity, origins of natural gas generated in high-over mature stage and cracking temperature of methane homologs were investigated in this study. The sapropelic source rock has a hydrocarbon expulsion efficiency of 30%-60% and 60%-80% in the major oil generation window(with Ro of 0.8%-1.3%) and high maturity stage(with Ro of 1.3%-2.0%) respectively; and the contribution ratio of kerogen degradation gas to oil cracking gas in total generated gas in high maturity stage is about 1:4. The degradation gas of kerogen accounts for 20%, the retained liquid hydrocarbon cracking gas accounts for 13.5%, and the amount of out-reservoir oil cracking gas(including aggregation type and dispersed oil cracking gas) accounts for 66.5%. The lower limit of gas cracking is determined preliminarily. Based on the new understandings, a model of the whole hydrocarbon-generating process of source rock is built.

Kinetic study of the hydrocarbon generation from Upper Paleozoic coals in Ordos Basin

Kinetic parameters were characterized for the formation of the C1—C5 hydrocarbons generating from Taiyuan and Shanxi coal in the Upper Paleozoic of the Ordos Basin, through pres-surized simulation experiment designed for the kinetic study of hydrocarbon generation. Based on the palaeogeothermal evolution of the Upper Paleozoic strata in the Ordos Basin, the formation and evolution of gas from Taiyuan and Shanxi coal in the eastern and central regions of the Ordos Basin were reproduced, and it is suggested that large scale secondary hydrocarbon generation does not exist during the uplifting and cooling process of the basin at the end of Early Cretaceous. Some of the factors affecting the behavior of the coal-generated gas were also discussed, and it is emphasized that the most fundamental element determining the hydrocarbon generation behavior is the characteristic of the precursor hydrocarbon-source rock.

地层孔隙热压生排烃模拟实验初步研究

热压生排烃模拟实验是研究烃源岩热演化机理的重要手段之一。现有模拟实验技术主要强调的是温度、压力和时间,忽视了地层流体压力、生烃空间、高温高压地层水及初次排烃等重要影响因素。利用自行研制的地层孔隙热压模拟实验仪,同时考虑影响烃源岩生排烃过程的多种因素,建立地层孔隙热压生排烃模拟实验技术,对比研究发现:流体压力、生烃空间和高温高压液态水跟温度、时间一样自始至终影响着沉积有机质的生烃演化,只是在不同演化阶段其影响程度和表现形式不同。在低成熟—成熟阶段,地层孔隙—高温高压液态水热体系对Ⅰ型干酪根黑色泥岩成烃过程的影响主要表现为延缓了油的生成,抑制了气体的生成,改变了干酪根的组成特征,提高了烃源岩的生油潜力。

海相碳酸盐岩烃源岩生排烃能力研究

在5000余块海相不同类型烃源岩样品的精细筛选和比较的基础上，选取了青藏高原侏罗系、冀北上元古界、云南禄劝泥盆系等34个样品进行了人工加水热压模拟实验。综合研究认为，海相烃源岩中碳酸盐岩相对泥页岩对干酪根生排烃具有较强的催化作用，可使生排总油高峰温度前移，更容易形成未熟-低熟稠油，排油效率增大，总产气、CO2和H2产率增高，总油、气携油、残留油、烃气及总烃产率也相对有所增加。这与α-碳原子形成自由基的催化反应、碳酸盐岩干酪根中浮游藻类含量相对较高以及碳酸盐对有机质及烃类的吸附作用弱有关。但是，含钙泥页岩（碳酸盐含量为5％～25％）总油等烃类产率相对最高。它主要多为封闭强还原环境下形成的富烃含钙页岩，干酪根类型好，有机质丰度高。

泥灰岩的生、排烃模拟实验研究

本文采用加水热模拟实验方法对东濮凹陷卫城地区下第三系低熟泥灰岩进行了生、排烃模拟实验研究，重点分析了液态产物（热解油、沥青Ａ、沥青Ｃ）的特征及演化规律。热解油中轻质烃（Ｃ６－Ｃ１４）占有重要的地位，其相对含量随演化程度的增高变化特征是从大到小然后再增大，轻质烃的准确定量为评价泥灰岩的生油量提供了重要参数；热解油、沥青Ａ、沥表Ｃ三者的产率及组成变化的对比研究反映了泥灰岩（碳酸盐岩）中不同赋存状态有机质对成烃的贡献以及排烃机制。

烃源岩有限空间温压共控生排烃模拟实验研究

烃源岩的生烃反应是在其限定的孔隙空间中承受高静岩压力和流体压力下进行的,然而受实验装置和条件的限制,目前大多数的生排烃模拟实验都是在一个低压、相对较大的生烃空间下进行的,与实际地质情况差异较大。通过对同一样品分别进行有限空间和常规高压釜方式加水模拟实验对比研究发现:(1)有限空间热压模拟实验的气态产物更接近地质实际。气体组分中烃气占有更大的比重;重烃气的保存下限大于常规模拟,延迟了重烃气向甲烷的转化;烯烃含量比常规加水模拟条件下更少,基本检测不到。(2)有限空间的限制使水介质参与成烃反应的作用增强,其限定空间内较高的流体压力延迟了油向烃气的转化过程,有利于液态油的生成和保存。(3)有限空间下高压液态水介质条件有利于烃类的排出。

海相碳酸盐岩排烃下限值研究

在灼烧过的方解石和蒙脱石及灰岩和泥岩中分别加入同一种有机质配制成不同有机碳含量的样品进行热解和加水热压模拟实验,结果表明,海相碳酸盐岩的烃吸附量一般在0.35 mg/g左右,变化在0.2～0.85 mg/g之间;泥页岩烃吸附量一般在1.25 mg/g左右,变化在0.46～2.62 mg/g之间.高成熟-过成熟海相碳酸盐岩排烃下限TOC值为0.08%左右,成熟海相富烃碳酸盐岩排烃下限TOC值为0.3%左右,排烃下限TOC值与烃源岩吸附烃含量、干酪根类型及有机质成熟度有关.

煤生烃过程中成熟度引起的碳同位素分馏效应

通过半封闭体系下的生排烃热模拟实验研究了3种煤在不同热解温度下的碳同位素分馏效应。研究结果表明,煤的有机质类型不同,成熟度造成的热解烃的碳同位素分馏效应也有差别,腐植煤的热解烃基于成熟度的碳同位素分馏效应大,而煤本身的碳同位素值随成熟度的变化不大。在较高成熟度时,二次裂解的概率大大增加,导致热解烃尤其是残留烃的正构烷烃单体碳同位素组成明显变重。同一烃源岩在不同温度下的热解烃正构烷烃单体的碳同位素组成曲线具有很大的相似性,说明在油源对比中正构烷烃单体碳同位素值曲线的形状和其数值一样都是重要的对比依据。

烃源岩生排烃模拟实验技术现状、应用与发展方向

烃源岩生排烃模拟实验已成为研究烃源岩生、排、滞油气机理的重要技术手段。对生排烃模拟实验技术的研究现状及发展趋势进行了归纳与总结。目前根据反应体系的开放程度,生排烃模拟实验方法可分为开放体系、封闭体系和限制体系3类;模拟实验的方式主要有单温阶累计生排油气模拟和多温阶连续生排油气模拟2种;实验边界条件主要有模拟的温度、压力体系、时间、样品形态及无机反应介质等5类。生排烃模拟实验在明确油气生、排、滞过程及其主控因素,建立不同类型沉积有机质的油气演化模式,评价沉积盆地的油气资源潜力和进行油气源对比与示踪等方面起到了重要的作用。目前的生排烃模拟实验具有局限性,需要在实验边界条件、源—储—藏协同成烃成藏物理模拟和多因素共控作用下油气形成动力学模拟方面进行更深入的研究。

辽河油田曙光欢喜岭潜山带 烃源岩生排烃模拟实验研究

对辽河油田曙光欢喜岭潜山带沙三段（Ｅｓ３） 和沙四段（Ｅｓ４） 典型的未成熟源岩样品进行了高温高压干体系的生排烃热压模拟实验。研究结果表明：３００ ～４００ ℃（Ｒｏ ＝０ ．３３ ％ ～１ ．３０ ％ ） 为该区域烃源岩的主要生排烃阶段；沙四段具有更好的生排油潜力，可能是曙光－ 欢喜岭潜山带较好的烃源岩；生排烃作用对排出油和残留油中生物标志物的组成具有明显的影响，在油／ 源对比时应特别注意。

烃源岩孔隙流体介质对石油初次运移的影响

利用自主研制的地层孔隙热压生排烃模拟仪,系统开展了氮气—水蒸气、水蒸气—液态水体系、液态水和无水体系系列生排烃模拟实验,通过对排油效率的分析对比,探讨了烃源岩孔隙流体介质对石油初次运移的影响。在生油气阶段,烃源岩孔隙空间是保持一定温度和压力的多组分(烃气、非烃气、石油、地层水)流体共存的一种相态。液态地层水是石油初次运移过程中不可缺少的运移载体。水可能是首先吸附在岩石矿物的表面,起到了一种"润滑剂"的作用,阻止了石油在矿物表面的吸附,从而有利于石油的运移。同时,生油气过程中伴生的大量的CO2,由于其独特的超临界特性,易于溶解孔隙流体中的石油,降低了油水之间的界面张力和石油的黏度,减小了石油运移阻力,促进了石油的初次运移。

湖相烃源岩排烃差异性模拟研究——以东营凹陷古近系沙三段为例

从岩石结构和有机质特征来说,烃源岩均具有很强的非均质性,以东营凹陷沙三段的块状泥岩、纹层泥岩和油页岩为例,采用烃源岩全岩(未粉碎)进行模拟实验,结合地质剖面,分析了该区烃源岩的排烃机理及其差异性。结果表明,生烃作用是烃源岩排烃的根本原因,早期是富集液态油的主要阶段,当液态油富集达到一定程度时开始排烃;主要的排烃期出现在液态油生成高峰及其之后,当液态油中的总烃(尤其是轻质烃类)大量生成时,排烃效率明显增大。各种原因形成的微层理和微裂缝是油气运移的优势通道。3类烃源岩的排烃效率明显不同,这与烃源岩的结构及演化阶段有关。

碳酸盐岩烃源岩生烃增压规律及其含义

碳酸盐岩由于成岩-固结早,烃源岩排烃的动力主要是水热增压和生烃增压。通过碳酸盐岩烃源岩不同有机碳含量样品温、压关系的模拟实验,建立了增压值与温度的数值关系模型。实验结果表明,碳酸盐岩烃源岩生烃过程中生烃增压值远高于水热增压值。碳酸盐岩烃源岩排烃动力的大小主要受烃源岩有机质丰度和温度的影响。对于同一烃源岩来说,随着热演化程度增高,生烃增压值迅速增大;当热演化程度相当时,生烃增压值与样品的有机碳含量成正相关关系。若烃源岩有机碳含量过低,烃源岩产生的生烃增压值不足以有效地把烃类排出烃源岩。由于碳酸盐岩烃源岩中含水量通常很低,则生烃增压特别是生气增压对排烃而言更为重要。因此,碳酸盐岩烃源岩遵循生烃—增压—超压—压力释放—排烃的动力学模式。

盐湖相有机质成烃模拟实验研究

通过泥岩和泥岩顶底板加ＮａＣｌ的生排烃模拟，指出盐湖相未成熟或低成熟石油是沉积岩石中分散有机质经化学降解聚集的产物，并对早期成烃机制进行了探讨，对常用的烃源岩母质类型、成熟度等参数提出了新的认识。

黄骅坳陷孔南地区油页岩的排烃模拟试验

油页岩在油气生成过程中的排烃效率是人们一直关心的问题。勘探实践证明,黄骅坳陷孔南地区孔店组和沙河街组页岩是重要生油岩,油页岩是能够有效并大量排烃的,但具体特征尤其是在较低演化阶段排烃效率如何仍是一个值得研究的问题。本研究通过模拟试验手段,对未成熟油页岩在不同演化阶段生、排烃特征进行了分析,建立了油页岩的生、排烃模式。认为孔南地区油页岩在低演化阶段具备了生、排烃能力,且排烃量较大。与该区同类型泥岩相对比,油页岩低演化阶段排烃效率低于泥岩,但绝对排烃量却高于泥岩,随演化程度增加两者的排烃效率趋于一致。这一认识应用到该地区资源评价当中,为油气勘探部署提供了重要依据。

碳酸盐岩排烃条件及其对烃源岩有机质丰度下限的影响

碳酸盐岩排烃问题一直是地球化学界争论和研究的焦点问题之一,也是模拟实验中的一个难点。通过对碳酸盐岩与泥岩生排烃过程中的产物和排烃动力的定量模拟实验研究,确定了碳酸盐岩烃源岩的有效排烃方式,讨论了碳酸盐岩在排烃临界条件下的有机质丰度的取值范围。实验结果表明,碳酸盐岩排烃模式与泥岩的模式不同,有其特殊的排烃方式;在碳酸盐岩排烃过程中生烃增压是主要的排烃驱动力;有机质丰度下限值不是一个定值,正好相反,随着热演化温度的不同,有机质丰度下限值也不尽相同。根据碳酸盐岩特殊的排烃模式,源岩有机碳含量0.4%～0.5%可能是满足碳酸盐岩源岩有效排烃条件的临界有机质丰度范围值。

不同热模拟方式下烃源岩干酪根演化特征红外光谱分析

烃源岩的生烃过程是在地层孔隙空间内有机质受温度、上覆岩层静岩压力和高地层流体压力(PVT-L共控)等多种作用下的一种复杂的物理化学反应过程。然而目前常用的生烃模拟实验(高压釜加水生烃模拟)大多是在一个低流体压力、无静岩压力、相对较大的生烃空间下进行的,与实际地质情况差异较大。选用南襄盆地泌阳凹陷核三段未熟泥岩分别开展了PVT-L共控和常规高压釜方式加水模拟实验,不同演化阶段干酪根的傅里叶变换红外光谱对比分析表明:(1)伴随着脂族结构裂解、含氧基团脱落及芳香结构缩合,干酪根演化明显呈现出缓慢生油、快速生油和结束生油3个阶段;(2)脂肪度参数IAL、饱芳比参数IL/R和含氧度参数IO表明,同等温度条件下常规高压釜加水模拟脂肪链和含氧基团的热裂解反应更为剧烈,PVT-L共控模拟则相对平缓,380℃时仍伴随有较强的生烃能力;(3)PVT-L共控模拟条件下饱和烃的芳构化程度更低,可能与其限定空间内较高的流体压力有关;(4)含氧度在成熟中期间歇的轻微增大,暗示水对干酪根生烃过程也许有重要的作用。2种不同模拟方式下干酪根红外光谱特征上的差别,暗示其在生烃反应机理上存在较大差异,在热模拟实验研究中要根据研究目的合理选择模拟方式,设置实验条件。