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通过对中国大陆科学钻探主孔地质及地震反射资料的综合研究,发现甲烷、二氧化碳与氦等气体异常与三分量地震反射带有关,在水平分量剖面上尤其明显.然而,在甲烷等气体异常存在的井段,结晶岩石的孔隙度仅为1%左右,难以说明产生地震响应的原由.主孔岩心地震波速测量结果表明,尽管结晶岩的孔隙度低,其中微裂隙含气会引起地震波速(尤其是S波速度)与饱水岩样相比明显降低,导致充气结晶岩石产生明显的地震响应.据此可以预测,如果中地壳部分岩石因水岩作用孔隙度提高并且充有天然气,中地壳顶部天然气会聚于孔隙度提高的结晶岩中的几率将大于地壳.由于这种会聚会引起低渗结晶岩石S波速度明显降低,地震方法将来可用于探测中地壳的天然气床.
Through the comprehensive study of the geologic and seismic reflection data of the main holes in the Chinese mainland, it is found that the gas anomalies such as methane, carbon dioxide and helium are related to the three-component seismic reflection band, especially on the horizontal component profile. However, , The porosity of the crystalline rock is only about 1%, which makes it difficult to explain the origin of the seismic response.The measurement results of the seismic wave velocity of the main hole indicate that although the micro-fractured rock contains low porosity, Especially the S-wave velocity) is obviously lower than that of saturated water samples, resulting in obvious seismic response of the inflated crystalline rocks.It can be predicted that if some rocks in the middle crust increase in porosity due to water-rock and are filled with natural gas, The probability of the top gas converging in the porosity-enhanced crystalline rocks will be greater than that of the crust, and the seismic methods may be used to probe the mid-crust natural gas bed in the future as this convergence causes a noticeable decrease in the S-wave velocity of the hypotonic crystalline rocks.