彭水区块页岩气地震检测方法研究

发布时间：2018-04-20 05:10

本文选题：页岩气 + 地震　；参考：《中国石油大学(华东)》2015年硕士论文

【摘要】：四川盆地及周缘上奥陶统五峰组一下志留统龙马溪组沉积于陆棚相滞流缺氧环境,而且富含笔石和有机质的黑色泥页岩发育。与美国页岩气盆地相比,四川盆地及周缘五峰组—龙马溪组页岩具有较为独特的地质条件,主要表现为志留系页岩具有沉积时代早、经历的地质历史长,并且经历了复杂的构造运动和热史。通过近期勘探认识,明确四川盆地及周缘页岩气富集高产主控因素包含了富有机质页岩的发育程度、保存条件、含气性和泥页岩的可压裂性等方面。彭水区块地区南方山地,地表起伏变化大,碳酸岩出露区地震资料信噪比低,残留向斜曲率比较大,二维地震资料偏移成像效果较差。采用渐进去噪方法的思想,就是在去除的“噪音”中再将其中很微弱的有效信号提取出来,并将之合理地反馈到地震数据中去,从而在去除噪音的基础上最大程度地保证有效信号的能量。采用最佳能量叠前时间偏移技术页岩气二维地震资料成像效果显著改善。在对研究区内井资料的测井曲线进行分析的基础上,利用测井曲线计算出对应的P波阻抗曲线,P波阻抗在高TOC页岩层段与其它页岩层段段有明显的区别,因此P波阻抗对高TOC页岩层有良好的识别能力,通过测井约束稀疏脉冲反演方法进行优质页岩厚度预测,彭水区块上奥陶统五峰组一下志留统龙马溪组下部优质页岩的厚度在21m-25m范围内。正常压实地层,随着深度增加,上覆压力变大,地层压实作用变强致使地层岩石中的孔隙度变小,地震波在孔隙度变小的岩石中传播速度会变高,在异常高压地层中,岩石孔隙度比正常压实岩石要大,岩石密度变低,地震波传播速度会变小。在精细速度分析的基础上,利用Fillippone法对上奥陶统五峰组一下志留统龙马溪组压力系数进行预测,研究区压力系数整体范围在0.9—1.15之间,保存条件一般。岩石物理分析表明,彭页1井龙马溪组底部至五峰组(井深2136米-2160米)页岩是最为有利的勘探目标,该段页岩具有高TOC,较大有效孔隙度,高脆性和低最小水平闭合压力等有利特征。岩石物理分析结果表明,纵横波速度比是TOC的敏感弹性参数,拉梅常数*密度是脆性的敏感弹性参数,密度是有效孔隙度的敏感弹性参数,最小水平闭合压力标量属性可以定性反映最小水平闭合压力大小;采用叠前反演技术可以反演以上各敏感弹性参数,并能进行定量解释。划分TOC含量高低的纵横波速度比门槛值为1.67,划分脆性矿物含量高低的拉梅常数*密度门槛值为33Gpa*g/cc或纵横波速度比1.67。综合优质页岩厚度、保存条件、含气性及脆性矿物含量,落实彭水区块桑柘坪向斜一类有利区263.01Km~2,二类有利区122.77Km~2。
[Abstract]:The lower Silurian Longmaxi formation in and around the upper Ordovician of Sichuan basin is deposited in the shelf facies anoxic environment and the black shale is rich in graptolite and organic matter. Compared with the American shale gas basins, the Sichuan Basin and the surrounding Wufeng formation-Longmaxi formation shale have more unique geological conditions, mainly because the Silurian shale has an early sedimentary age and a long geological history. And experienced a complex tectonic movement and thermal history. Through the recent exploration, it is clear that the main controlling factors of gas enrichment and high yield in Sichuan basin and peripheral shale include the development degree, preservation condition, gas-bearing property and fracturing ability of shale. In the southern mountainous area of Pengshui block, the surface fluctuates greatly, the signal-to-noise ratio of seismic data in outburst area of carbonate rock is low, the curvature of residual syncline is relatively large, and the migration imaging effect of two-dimensional seismic data is poor. The idea of gradual de-noising is to extract the weak effective signal from the "noise" and feed it back into the seismic data reasonably. Therefore, on the basis of noise removal, the energy of the effective signal is guaranteed to the maximum extent. The best energy prestack time migration technique is used to improve the imaging effect of shale gas 2D seismic data. Based on the analysis of logging curves of well data in the study area, the corresponding P wave impedance curve and P wave impedance curve are calculated by using the log curves. The P wave impedance curves are obviously different from those of other shale formations in high TOC shale formation. Therefore, P-wave impedance has good recognition ability for high TOC shale formation, and the high quality shale thickness can be predicted by logging constrained sparse pulse inversion method. The thickness of high quality shale in lower part of Silurian Longmaxi formation in upper Ordovician Wufeng formation in Pengshui block is within 21m-25m range. In normal compacted strata, with the increase of depth, the overlying pressure increases, the formation compaction becomes stronger, the porosity of formation rock becomes smaller, the velocity of seismic wave propagates in rock with smaller porosity will become higher, and in the abnormal high-pressure formation, The porosity of rock is larger than that of normal compacted rock, the density of rock becomes lower and the velocity of seismic wave propagation becomes smaller. On the basis of fine velocity analysis, the pressure coefficient of Wufeng formation of Upper Ordovician and Longmaxi formation of Silurian is predicted by Fillippone method. The whole range of pressure coefficient in the study area is between 0.9-1.15, and the preservation conditions are general. The petrophysical analysis shows that the shale from the bottom of Longmaxi formation to Wufeng formation (well depth of 2136 m -2160 m) is the most favorable target for exploration, which has high TOC and high effective porosity. The advantages of high brittleness and low horizontal closure pressure. The results of rock physical analysis show that the velocity ratio of longitudinal and shear waves is a sensitive elastic parameter of TOC, the Lamy constant * density is a sensitive elastic parameter of brittleness, and the density is a sensitive elastic parameter of effective porosity. The minimum horizontal closed pressure scalar attribute can reflect the minimum horizontal closure pressure qualitatively, and the prestack inversion technique can be used to invert the above sensitive elastic parameters and can be quantitatively interpreted. The P / S wave velocity ratio threshold of TOC content is 1. 67, and the Lamy constant * density threshold of brittle mineral content is 33Gpa*g/cc or P / S wave velocity ratio 1. 67. By synthesizing the thickness of high quality shale, preservation conditions, gas content and brittle mineral content, a favorable area of 263.01km ~ (-2) and a favorable area of 122.77km / m ~ (2) in the Sangzuping syncline in Pengshui block are carried out.
【学位授予单位】：中国石油大学(华东)
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P618.13;P631.4

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