【摘要】：有機質(zhì)是含氣頁巖的重要組分之一,有機質(zhì)含量及類型在相當大程度上控制著頁巖的孔隙度及含氣性。前人工作多關(guān)注頁巖礦物組分及其賦存方式所導(dǎo)致的聲速及力學(xué)性質(zhì)各向異性方面,而對有機質(zhì)含量與頁巖聲波傳播響應(yīng)特性的關(guān)系則很少研究。以鄂爾多斯盆地三疊系延長組長7段富有機質(zhì)頁巖為研究對象,利用自行研制的SCMS-J型聲電測試儀,采集15MPa圍壓下頁巖縱/橫波傳播信息,分析有機質(zhì)含量對縱/橫波傳播速度及頁巖力學(xué)性能的影響,并運用快速傅里葉變換對采集的巖樣聲波波形數(shù)據(jù)進行頻譜分析。研究表明:(1)縱/橫波傳播速度隨著有機質(zhì)含量增加而減小,縱/橫波波速比隨著有機質(zhì)含量增加而增大;(2)頁巖動態(tài)剪切模量G、動態(tài)體積模量K和動態(tài)彈性模量E隨著有機質(zhì)含量增加而降低,而泊松比v隨著有機質(zhì)含量增加而增大;(3)有機質(zhì)含量越高,高頻部分吸收越明顯,主頻向低頻移動,形心頻率f_c大小與有機質(zhì)含量呈負相關(guān)。研究成果對基于聲波測井信息評價頁巖有機質(zhì)含量及含氣性具有一定的借鑒意義。
[Abstract]:Organic matter is one of the important components of gas-bearing shale. The content and type of organic matter control the porosity and gas-bearing property of shale to a great extent. Previous studies have focused on the anisotropy of acoustic velocity and mechanical properties caused by shale mineral components and their occurrence patterns, but little on the relationship between the content of organic matter and the response characteristics of shale acoustic wave propagation. Taking the organic shale of Chang 7 member of the Triassic Yanchang formation in Ordos Basin as the research object, using the SCMS-J type acoustoelectric tester developed by ourselves, the longitudinal / shear wave propagation information of shale under 15MPa confining pressure is collected. The influence of organic matter content on the propagation velocity of longitudinal / shear wave and the mechanical properties of shale is analyzed. The spectrum analysis of acoustic wave data of rock samples is carried out by using fast Fourier transform (FFT). The results show that: (1) the propagation velocity of P / S wave decreases with the increase of organic matter content, and the velocity ratio of P / S wave increases with the increase of organic matter content; (2) dynamic shear modulus G, dynamic bulk modulus K and dynamic elastic modulus E decrease with the increase of organic matter content, while Poisson's ratio v increases with the increase of organic matter content; (3) the higher the organic matter content, the more obvious the absorption of the high frequency part is, the main frequency moves to the low frequency, and the centroid frequency FSC is negatively correlated with the organic matter content. The results can be used for reference in the evaluation of shale organic matter content and gas content based on acoustic logging information.
【作者單位】： 西南石油大學(xué)油氣藏地質(zhì)及開發(fā)工程國家重點實驗室;
【基金】：國家自然科學(xué)基金面上項目“富有機質(zhì)頁巖氧化致裂增滲加速氣體傳輸機理研究”(編號:51674209) 非常規(guī)油氣層保護四川省青年科技創(chuàng)新研究團隊項目(編號:2016TD0016)聯(lián)合資助
【分類號】：P618.13;P631.81

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