寺家庄矿构造煤物性特征及应用研究

发布时间：2018-03-07 23:17

本文选题：温压条件　切入点：构造煤　出处：《太原理工大学》2017年硕士论文　论文类型：学位论文

【摘要】：一定厚度的构造煤的存在常是煤与瓦斯突出发生的必要前提,同时煤层气的富集区也往往与构造煤的发育区域相关。随着我国能源结构的逐渐转化和大规模煤层气压裂开采的需要,因此,在温压条件下开展不同煤体结构煤样的超声波实验研究是进行井震联合勘探预测瓦斯富集区的物理基础,这对利用地球物理勘探技术探测构造煤赋存分布、预测突出危险性具有重要的指示作用。由于构造煤具有煤体强度低、孔隙度高、渗透率低等特点导致室内制样比较困难,通过对不同煤体结构煤岩样制样方法的综合查阅,本文以寺家庄煤矿为采样点,针对不同煤体结构的煤岩样采取不同的制样方法,并对煤岩样在温压条件下的实验进行超声波测试与统计分析,分析了煤岩样的纵横波速度特征、各向异性特征、衰减特性和弹性模量,最后以实验测试物性参数为基础建立地震地质模型进行AVO正演模拟,通过上述研究分析得出寺家庄矿不同煤岩类型弹性特征:(1)同一变质程度不同破碎类型煤样的纵波、横波速度与煤岩视密度之间的相关性较差,而V_P、V_S之间表现出较好的相关性。常温常压条件下,纵、横波速度的关系式:V_s = 0.3878V_P + 235.24,R~2=0.9,围压在1OMPa条件下,纵、横波速度的关系式:V_s = 0.3408V_P + 406.04,R~2=0.7982;不同煤体结构煤样的纵横波平均波速从大到小依次为原始结构煤、碎粒～糜棱煤、碎裂煤。煤样的波速与弹性模量(μ、E、K和λ)呈较强线性相关关系。横波速度存在不同方向的差异性。说明沿煤层层理方向表现出了横波的各向异性特征。(2)不同类型煤岩样的纵横波速度与围压之间均呈对数相关关系但随着温度的增加,煤样的纵横波速度又发生不同程度的降低,在煤系地层的埋深范围内,围压和温度对波速的影响是相互制约的,但围压起主导作用。在相同围压范围内,两种不同类型构造煤的Qp、Qs较Vp、Vs的变化幅度大。(3)不同夹层组合煤层模型AVO响应特征结果表明:构造煤和夹矸层对煤层AVO结果的影响相反。夹矸与构造煤夹层的存在会使煤层反射系数发生变化,而反射系数在一定程度上是反射波的能量的体现,可以将煤层的均方根振幅或瞬时振幅幅值出现异常高的位置作为构造煤可能存在的依据。
[Abstract]:The existence of a certain thickness of tectonic coal is often the necessary prerequisite for the occurrence of coal and gas outburst. At the same time, the rich area of coalbed methane is often related to the development of tectonic coal. With the gradual transformation of energy structure and the need of large-scale coalbed methane fracturing production in China, therefore, The ultrasonic experimental study of coal samples with different coal structures under the condition of temperature and pressure is the physical basis for the combined exploration of well and earthquake to predict the gas accumulation area, which can be used to detect the occurrence and distribution of tectonic coal by using geophysical exploration technology. The prediction of outburst risk plays an important role in indicating that structural coal has the characteristics of low coal mass strength, high porosity and low permeability, which makes it difficult to prepare indoor samples. In this paper, taking Sijiazhuang coal mine as sampling point, different sampling methods are adopted for coal rock samples with different coal body structures. Ultrasonic testing and statistical analysis of coal and rock samples under temperature and pressure conditions are carried out, and the characteristics of longitudinal and shear wave velocities of coal and rock samples are analyzed. Anisotropy, attenuation and elastic modulus. Finally, the seismic geological model is established based on the physical parameters of the experiment, and the AVO forward modeling is carried out. Through the above research and analysis, it is concluded that the elastic characteristics of different types of coal and rock in Sijiazhuang mine are: (1) the correlation between shear wave velocity and apparent density of coal rocks is poor, and the longitudinal wave and shear wave velocity of different broken coal samples of the same metamorphism degree are different. Under normal temperature and atmospheric pressure, the relation between longitudinal and shear wave velocities is:: Vs = 0.3878 VSP = 0.3878VP235.24R0. 9. The confining pressure is 1OMPa. The relation of shear wave velocity is as follows: v _ s = 0.3408V _ T _ P _ 406.04 / R _ ~ ~ ~ _ ~ ~ ~ _ _ _, Broken coal. Strong linear correlation between wave velocity and modulus of elasticity (渭 _ (E) K and 位) of coal samples. There are differences in different directions of shear wave velocities. It is shown that the anisotropy of shear waves is shown in the direction of seam bedding. 2) different types of coal. The longitudinal and shear wave velocities of rock samples are logarithmic correlated with confining pressure, but with the increase of temperature, The longitudinal and shear wave velocities of coal samples decrease in varying degrees. In the depth range of coal measure strata, the influence of confining pressure and temperature on wave velocity is mutually restricted, but the confining pressure plays a leading role in the same confining pressure range. The AVO response characteristics of two different types of structural coals are larger than that of VpTVs) the results of AVO response of different intercalation combined coal seam models show that the influence of tectonic coal and gangue layer on the AVO results of coal seam is opposite, and the existence of gangue and tectonic coal intercalation. Will change the reflection coefficient of the coal seam, The reflection coefficient to some extent is the reflection of the energy of the reflected wave. The abnormal position of the RMS amplitude or the instantaneous amplitude amplitude of the coal seam can be taken as the basis for the possible existence of the tectonic coal.
【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TD713;TQ531.1

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