沁南地区高阶煤全尺度孔隙结构表征及流体差异流动性

发布时间：2018-04-28 10:31

本文选题：沁南地区 + 高阶煤储层　；参考：《中国矿业大学》2017年硕士论文

【摘要】：煤储层孔隙结构类型是控制储层流体流动差异性的根本原因。论文在系统分析沁南地区高阶煤储层基本特征的基础上,综合运用高压压汞、低温液氮吸附和低温CO2吸附实验对研究区样品进行全尺度孔隙结构表征,建立了全尺度孔隙结构模型,进而探讨了储层基本特征及孔隙结构特征对流体流动差异性的控制作用。结果显示,以等粒度无烟煤1号和石英砂岩为对比背景,指出高阶煤各级孔隙均较为发育,孔比表面积极高,尤其以超微孔孔隙极为发育,无烟煤1号微孔-过渡孔较为发育,而石英砂岩各级孔隙都均不发育。基于分形方法,指出压汞和低温液氮孔径拼接孔隙尺度为100nm,实现了压汞-液氮-低温CO2全尺度孔隙结构拼接,识别出3种高阶煤全尺度孔隙结构类型。各级及全尺度孔容和比表面积随镜质组、固定碳(煤级)增加及粒度减小总体呈正相关相关,而与惰质组、矿物含量和灰分产率负相关。研究区样品甲烷吸附能力随镜质组、固定碳含量的增加而增加,随惰质组、灰分产率的增加而降低,与挥发分产率无明显关系;随着压汞孔体积、压汞孔比表面积、低温液氮BJH总孔体积、BET比表面积、低温CO2吸附DFT总孔体积和孔比表面积的增加而增加。随着粒度减小,VL由31.55 cm3/g增加至47.41 cm3/g,PL由1.07MPa波动降低至0.49MPa。随着镜质组含量增加研究区样品可离出水含量表现出先减少后增加的趋势,可压入水含量变化规律不明显;随着惰质组含量的增加,可离出水含量减少而可压入水含量增加;随这灰分产率增加,水可动性增加;固定碳含量增加,水的可流动性减弱;总孔容及微孔和过渡孔孔容的增加,水的可动性增强;随着润湿角的增大,可离出水含量增加而可压入水含量波动较大,变化规律不明显。
[Abstract]:The type of pore structure in coal reservoir is the fundamental reason to control the difference of fluid flow. On the basis of systematic analysis of the basic characteristics of high-order coal reservoirs in Qinnan area, the pore structure of samples in the study area was characterized by high-pressure mercury injection, low-temperature liquid nitrogen adsorption and low-temperature CO2 adsorption experiments. The full-scale pore structure model is established, and the control effect of reservoir basic characteristics and pore structure characteristics on fluid flow difference is discussed. The results show that the pores of higher order coal are relatively developed and the pore specific surface is positive, especially the ultramicro pore and the transition pore of anthracite No. 1 are relatively developed in comparison with quartz sandstone and anthracite No. 1 as the contrast background, the results show that the pore ratio of high-order coal is relatively high, especially the ultramicro pore is extremely developed. The pores of quartz sandstone are not developed at all levels. Based on the fractal method, it is pointed out that the pore size of mercury injection and low temperature liquid nitrogen pore splicing is 100 nm, and the full scale pore structure splicing of mercury-liquid nitrogen and low temperature CO2 is realized, and three types of high-order coal full-scale pore structures are identified. The increase of fixed carbon (coal grade) and the decrease of particle size were positively correlated with the increase of fixed carbon (coal grade) and the decrease of particle size in the vitrinite group, but negatively correlated with the mineral content and ash yield in the inertinite group. The methane adsorption capacity of the samples increased with the increase of the fixed carbon content in vitrinite group, and decreased with the increase of ash yield in the inertinite group, which had no obvious relationship with the volatile yield, and the specific surface area of mercury porphyry pore increased with the volume of mercury injection pore, and the specific surface area of mercury injection pore increased with the increase of ash yield in inertinite group. The total pore volume of low temperature liquid nitrogen (BJH) was increased with the increase of the total pore volume and pore specific surface area of DFT adsorbed by low temperature CO2. As the particle size decreases, the VL increases from 31.55 cm3/g to 47.41 cm 3 / g PL from 1.07MPa fluctuation to 0.49 MPA. With the increase of vitrinite content, the content of extractable water decreased first and then increased, but the change of compressible water content was not obvious, with the increase of inertinite content, the content of detachable water decreased and the content of compressible water increased. With the increase of ash yield, the water mobility increases; the fixed carbon content increases, the water fluidity weakens; the total pore volume and the micropore and transition pore volume increase; the water mobility increases with the increase of wetting angle. The content of removable effluent increased, but the content of compressible water fluctuated greatly, but the law of change was not obvious.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P618.13

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