【作者】 李吉焱；

【导师】 单玄龙；

【作者基本信息】 吉林大学 ， 矿产普查与勘探， 2014， 博士

【摘要】 烃源岩与火山岩沉积接触的组合关系对油气成藏尤为重要，岩浆活动带来的火山物质对有机质的生烃及油气的成藏有重要的影响。火山岩在形成过程中或之后伴有一定量的火山流体存在，火山流体对周围地层化学性质的影响十分显著。火山流体对烃源岩的生排烃有复杂的作用过程，包括加氢作用、加热作用、催化作用等。由于火山流体的成分复杂，模拟实验难于操作和定量分析，其对烃源岩生烃影响的热模拟实验较少。本文将从火山流体的热模拟的实验着手，研究火山流体对烃源岩生烃的影响，建立火山流体运动演化的数学模型，并以松辽盆地徐家围子断陷为例，对区域内的火山流体运动演化进行了解剖，预测了徐家围子断陷火山流体的流动趋势并圈定火山流体的影响范围。具体的研究内容和认识包括以下3个方面：（1）不同火山流体对烃源岩生烃影响的讨论本研究经过168次实验，首次实现了酸性和基性火山流体对烃源岩生烃产物的半定量-定量评价。实验结果显示，300-350℃酸性流体对非烃和烃类气均具有促进作用；基性流体抑制非烃气体产生，对烃类气体有先促进、后抑制的作用。400-450℃两种火山流体对烃类气体均呈明显抑制作用，对非烃气体呈促进作用。基性流体影响了液态饱和烃产物成分，使碳数范围有缩小趋势；酸性流体对液态饱和烃成分无影响。300℃-350℃酸性流体对液态烃产量有促进作用，基性流体对液态烃产量有抑制作用；400℃-450℃酸性、基性流体对液态烃产量均具有促进作用。（2）热模拟数据多元分析的讨论将实验数据进行经验正交函数分析，分析结果表明温度与CH4、C2、C3、iC4-nC5、总烃、总非烃和总气体产量呈正相关，而与CO2、CO、H2S气体产量呈负相关。热模拟实验存在临界温度，当实验温度小于临界温度时，产气量随温度的升高而增大，当实验温度大于临界温度时，产气量随温度的升高而降低。干燥体系的临界温度存在于350℃-400℃之间。流体体系的临界温度存在于400℃-450℃之间，酸性和基性火山流体均使产气临界温度升高，火山流体条件下的烃源岩生气窗口变宽，增加了天然气生成量。（3）火山流体运动演化数值模拟研究及典型实例解剖火山流体的运动演化取决于火山流体本身的成分、温度和压力等因素。一般来说，火山流体中SiO2和Al2O3含量越高，粘度越高，而火山流体的中的挥发性物质却可以降低火山流体的粘度。火山流体的粘度、围岩的孔渗特征、地层的压力等条件决定了火山流体的分布范围。本文以松辽盆地徐家围子断陷为例，利用火山岩的全岩成分，计算特定温压条件下火山流体的密度、粘度等参数。同时，依据现今地层的物性和物探数据恢复徐家围子断陷的古埋深、古孔隙度和古地层压力。在此基础上将流体势的概念引入到火山流体的运动演化的数值模拟中，利用以上数据首次计算徐家围子断陷的古火山流体势，并最终圈定徐家围子营一段火山流体对沙河子烃源岩的影响范围约628km2，徐家围子营三段火山流体对沙河子烃源岩的影响范围约161km2。更多还原

【Abstract】 Combination of source rocks and volcanic sedimentary contact is particularlyimportant for hydrocarbon accumulation. The volcanic materials brought by magmationhave important implications for hydrocarbon generation and formation reservoir. Duringor after the volcanic rocks forms together with a quantity of volcano fluids which has asignificant influence on the chemical properties of surrounding strata. The process ofvolcano fluids effect on source rocks is very complex which includes hydrogenation,heating effect, catalysis, and so on. The simulation experiment about volcano fluids effecton sources rocks is hard to operate and the data are difficult to achieve quantitativeanalysis caused by complex composition of volcano fluids. Based on thermal simulationexperiment, the impact of volcanic fluids on source rocks is studied, the mathematicalmodel of the motion evolution of the volcanic fluids is builded and the motion evolutionlaw of volcanic fluids is analyzed in Xujiaweizi Fault Depression of Songliao Basin.Themigration of volcanic fluids is marked.The areas influenced by volcanic fluids aredelineated by using the Laplacian operator. In a summary, the research contents andconclusions basically including the following three points:(1) The discussion about different kinds of volcanic fluids effect on different kinds ofsource rocks hydrocarbon generation.In this study, after168experiments, it is the first time for the semi-quantitative andquantitative evaluation of acidic and basic volcanic fluids effect on hydrocarbongeneration of source rocks. The results of experimental show that in the range of300℃-350℃, acidic volcanic fluids plays both a role in promoting for non-hydrocarbon andhydrocarbon gas. The basic volcanic fluids have an inhibition for non-hydrocarbon gasesgeneration, to hydrocarbon gases show that firstly promoting, then inhibition effect. In the range of400℃-450℃, both volcanic fluids show a significant inhibition to hydrocarbongases, while a promoting to the non-hydrocarbon gases. The basic volcanic fluids effect onthe component of liquid saturated hydrocarbon by narrowing its carbon number range.And there is no effect on the acidic volcanic fluids doing to the component of liquidsaturated hydrocarbon. In the range of300℃-350℃, acidic volcanic fluids play a role inpromoting effect for liquid hydrocarbon generation, and the basic volcanic fluids play arole in inhibiting the quantity of liquid hydrocarbon generation. In the range of400℃-450℃, both acidic and basic volcanic fluids have a role in promoting effect for liquidhydrocarbon production.(2) The discussed on the multivariate analysis of thermal simulation experimentaldata.The experimental data are analyzed through empirical orthogonal function.Theresults show that the temperatures have a positive correlation with CH4、C2、C3、iC4-nC5,total hydrocarbons and total non-hydrocarbon and total gas yield, while have a negativecorrelation with CO2、CO、H2S gas yield. There is a critical temperature in the thermalsimulation experiment, when the experimental temperature is below critical temperature,gas production increases with increasing temperature, when the experimental temperatureisabove critical temperature, the gas production decreases with increasing temperature.The critical temperature of the dry system is exist in350℃-400℃. while the fluids systemin400℃-450℃which shows that acidic and basic volcanic fluids make the criticaltemperature go up.(3) The numerical simulation of volcanic fluids evolution and typical examplesanalysis.The mobility of volcanic fluids is depended on many factors, but primarily oncomposition, temperature, and pressure. Generally, a higher content of SiO2and Al2O3inthe volcanic fluids can result in an increased viscosity. However, volatiles contained in thevolcanic fluids can reduce its viscosity. Factors such as viscosity, porosity, permeabilitycharacteristics of surrounding rocks and formation pressure, determine the distribution range of the volcanic fluids. This article takes Xujiaweizi Fault Depression in Songliaobasin as an example, using the whole-rock compositions of volcanic rocks to calculatevolcanic fluids parameters such as density, viscosity under the specific temperature andpressure conditions. At the same time, according to physical property of present formationand geophysical data, ancient burial depth, ancient porosity and ancient formation pressurewere recovered. On this basis, concept of volcanic fluids potential is introduced into thenumerical simulation of evolution of volcanic fluids. All above the data are used tocalculate volcanic fluids potential for the first time in Xujiaweizi Fault Depression.Ultimately, we concluded the results in Xujiaweizi that the influence area of volcanicfluids in Yingcheng Formation I to the source rocks of the Shahezi Formation is about628km2, while Yingcheng Formation III influences161km2.更多还原