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在实验室条件下,利用透射波研究砂岩含水含气的特性。采用超声仪作激发装置;波形瞬态记录仪作接收装置;微机处理,证实和发现了一些问题:(1)在实验室内进行HCI检测的结果和在一般的计算机上所得的结论基本一致,即主频(F_(m~2))、平均频率F_(me)降低,频带宽度(B_w)减小,低频带通面积(A_1)以及它与频带总面积(A_s)的比值增大对预测油气是有利的。(2)A_1/A_s指标比较稳定、灵敏,其次是A_1,最后才是B_w、F_(me)和F_(ma)。(3)低的中心频率及频带宽度对A_1及A_1/A_s有不同程度的影响,当带宽不变,中心频率选取46.8kc时,A_1及A_1/A_s相对变化最大;当中心频率不变,选取的低频带通宽度越小,A_1及A_1/A_s变化越灵敏。(4)HCI指标与砂岩孔隙含气百分比有关系,当含气量由0到50—60％时,F_(ma)、F_(me)、B_w相应减小,A_1及A_1/A_s相应增大,但是含气量继续增大时,HCI指标出现相反的显示。(5)从岩石的滤波特性和弹性系数中有可能提取新的检测参数。
Under laboratory conditions, the characteristics of water-bearing and gas-bearing sandstone are studied by using transmitted waves. Using ultrasound as the excitation device; waveform transient recorder as the receiving device; computer processing, confirmed and found some problems: (1) in the laboratory HCI test results and the conclusions obtained in the general computer is basically the same, Ie, the frequency (F_ (m ~ 2)), the decrease of the average frequency F me, the decrease of the bandwidth B_w, the increase of the ratio of the low frequency bandpass area A_1 to the total area of the frequency band A_s, Oil and gas is good. (2) The A_1 / A_s index is stable and sensitive, followed by A_1 and finally B_w, F_ (me) and F_ (ma). (3) The low center frequency and bandwidth affect A_1 and A_1 / A_s to some extent. When the bandwidth is constant and the center frequency is 46.8kc, A_1 and A_1 / A_s have the largest relative change. When the center frequency is constant, The lower the bandwidth of the low frequency band, A_1 and A_1 / A_s change the more sensitive. (4) The HCI index is related to the percentage of sandstone pore gas. When the gas content is from 0 to 50-60%, the F_ (ma), F_ (me) and B_w decrease correspondingly, while A_1 and A_1 / A_s increase correspondingly. However, when the gas content continues to increase, the HCI indicator shows the opposite. (5) It is possible to extract new detection parameters from the rock’s filtering and spring constants.