本文選題：射線彈性阻抗　切入點(diǎn)：致密砂巖氣藏　出處：《西北大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：致密氣藏孔隙度低,滲透率低,地震識(shí)別難度大,找尋新技術(shù)識(shí)別致密儲(chǔ)層流體一直是地球物理學(xué)研究的重要內(nèi)容之一。鄂爾多斯盆地北部蘇里格氣田中生界和古生界儲(chǔ)層流體分布規(guī)律復(fù)雜,井位部署難度大,現(xiàn)有地震預(yù)測(cè)方法難以有效識(shí)別流體,針對(duì)此問(wèn)題,本文提出了一種基于孔隙介質(zhì)巖石物理理論的AVO與射線彈性阻抗流體檢測(cè)新技術(shù),建立致密氣藏地震流體檢測(cè)的有效方法。首先,基于偶極橫波測(cè)井資料建立一種改進(jìn)的Xu-White方法預(yù)測(cè)孔隙介質(zhì)氣層段的橫波速度;其次,通過(guò)模擬合理準(zhǔn)確的巖石物理模型,分析巖石物理參數(shù)對(duì)彈性參數(shù)的影響程度及敏感性,完成角度域和射線參數(shù)域的兩層模型和井模型射線彈性阻抗AVO正演模擬,分析含氣飽和度對(duì)反射振幅的影響,通過(guò)研究AVO曲線分析REI和EI的精度;最后,根據(jù)理論研究以及交會(huì)圖分析,找尋流體識(shí)別的敏感參數(shù),在反演的射線彈性阻抗剖面上完成對(duì)巖性和流體的識(shí)別。研究表明:1)計(jì)算混合流體彈性參數(shù)時(shí),Brie經(jīng)驗(yàn)公式比Wood方程對(duì)含氣飽和度的變化更為敏感,可以更好的模擬不同含氣飽和度下的彈性參數(shù);2)孔隙度、含氣飽和度、泥質(zhì)含量等的變化對(duì)彈性參數(shù)(縱波速度、橫波速度、密度)的影響均較大;3)通過(guò)改進(jìn)Xu-White方法中泥巖孔隙縱橫比的計(jì)算,擬合泥巖孔隙縱橫比與砂質(zhì)含量的非線性公式,預(yù)測(cè)的孔隙介質(zhì)氣層段橫波速度與實(shí)測(cè)橫波平均誤差為5.2%;4)建立角度域和射線參數(shù)域兩層介質(zhì)模型和井模型正演模擬,分析不同含氣飽和度對(duì)射線彈性阻抗及反射振幅的影響,通過(guò)AVO分析研究REI和EI的精度,得到REI精度更高的結(jié)論;5)射線參數(shù)域隨射線參數(shù)變化,反射系數(shù)的變化率更大,變化幅度更明顯,較角度域來(lái)說(shuō),更能直觀清楚的反映出反射振幅的變化規(guī)律和趨勢(shì);6)射線參數(shù)p=0.10的射線彈性阻抗REI值與縱波速度的交會(huì)圖能很好的區(qū)分氣層和非氣層,可以在交會(huì)圖上建立巖性和流體識(shí)別的敏感參數(shù);7)使用流體識(shí)別的敏感參數(shù),在射線參數(shù)p=0.10的射線彈性阻抗反演剖面上完成儲(chǔ)層流體的識(shí)別,識(shí)別結(jié)果與單井日產(chǎn)氣量相對(duì)應(yīng),效果較好。
[Abstract]:The porosity of tight gas reservoir is low, the permeability is low, and the seismic identification is difficult. Finding new techniques for identifying tight reservoir fluids has always been one of the important contents in geophysics. The fluid distribution of Mesozoic and Paleozoic reservoirs in Sulige gas field in the north of Ordos Basin is complicated and the well location is difficult to deploy. It is difficult to identify fluids effectively by existing seismic prediction methods. In this paper, a new technique of AVO and ray elastic impedance fluid detection based on rock physics theory in porous media is proposed. An effective method for seismic fluid detection in tight gas reservoirs is established. Firstly, an improved Xu-White method is established based on dipole shear wave logging data to predict the shear wave velocity of gas reservoirs in porous media. The influence degree and sensitivity of rock physical parameters on elastic parameters are analyzed. The forward modeling of ray elastic impedance (AVO) in angle domain and ray parameter domain is completed, and the effect of gas saturation on reflection amplitude is analyzed. The accuracy of REI and ei is analyzed by studying the AVO curve. Finally, according to the theoretical research and cross plot analysis, the sensitive parameters of fluid identification are found. The lithology and fluid are identified on the inverse ray elastic impedance profile. The results show that the Brie empirical formula is more sensitive to the change of gas saturation than the Wood equation in calculating the elastic parameters of mixed fluid. It can better simulate the change of porosity, gas saturation and mud content to elastic parameters (longitudinal wave velocity, shear wave velocity, etc.) under different gas saturation. By improving the calculation of the aspect ratio of mudstone porosity in the Xu-White method, the nonlinear formula of the ratio between the aspect ratio of the shale pore and the sand content is fitted. The predicted shear wave velocity of gas reservoir in porous media and the average error of measured shear wave are 5. 2 and 4) the forward modeling of two layers medium model and well model in angle domain and ray parameter domain are established, and the influence of different gas saturation on the elastic impedance and reflection amplitude of ray is analyzed. By AVO analysis, the accuracy of REI and ei is studied, and the conclusion that the precision of REI is higher than that of REI is obtained. The variation rate of reflection coefficient is larger and the range of variation is more obvious than that of angle domain. More intuitively and clearly reflects the reflection amplitude change law and trend (6) ray parameter p0. 10 ray elastic impedance REI value and longitudinal wave velocity cross plot can distinguish gas layer and non gas layer very well. The lithology and the sensitive parameters of fluid identification can be established on the intersection diagram. Using the sensitive parameters of fluid identification, the reservoir fluid can be identified on the ray elastic impedance inversion section of ray parameter p0. 10. The recognition results correspond to the daily gas production of a single well. The effect is good.
【學(xué)位授予單位】：西北大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：P618.13;P631.4
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本文編號(hào)：1640173