用三维地震资料预测裂缝

裂缝性油气藏的裂缝分布规律研究是当今石油界公认的难题，单纯用测井资料研究尚有许多困难，用地震资料研究裂缝日益显现优势。应用三维地震资料，通过分析裂缝发育带地质特征，拾取由裂缝引起的地震波传播速度、频率和振幅差异，提出了用地震波运动学和动力学特征进行裂缝预测的方法。研究认为，裂缝发育带地震波传播速度下降、频率降低、振幅增大，能量显著加强。据此，在三维地震数据体中，可划分出裂缝发育带。天然裂缝系统是一个分形体系，可用分形理论建立裂缝分布的实际模型。地震道是一个混沌的反射序列，其分数维（ｆｒａｃｔａｌｄｉｍｅｎｓｉｏｎ，记为Ｄ）反映了反射系列的复杂程度，Ｄ值越大、越稳定，说明裂缝越发育。该方法用于柴达木盆地南翼山油田，所预测的裂缝发育带已被钻井和岩心观察所证实。应用该方法的过程中，要研究地质背景，结合测井、钻井、生产测试等动态资料，分析储集层特征，明确影响地震速度、频率和振幅的其它因素，确保所提取的速度、频率和振幅异常只是由裂缝引起的。预测要与钻井裂缝显示、测井裂缝定量解释相结合，用测井资料对井旁道进行准确的标定，尽量消除地震信息的多解性，提高裂缝预测精度。图２参３（邹冬平摘）

Fracture determination by means of 3 dimensional seismic data.

A study on the regularity of fracture distribution is recognized as a difficult issue in the world petroleum industry. Troubles are encountered if using logging data only and the superiority of seismic data interpretation is observed gradually. By an analysis of the geological characteristics, picking up the differences in the speed, frequency, and amplitude in seismic wave propagation a prediction method of fracture distribution by means of kinematic and kinetic characteristics of seismic waves is suggested. Results of study show that in well developed fractured zone, the propagation of seismic ware is characterized by a decrease of speed, a lowering of frequency, an increase of amplitude, and an enhancement of energy. The fracturing zone can be determined in the 3 dimensional seismic data cube according to these techniques. Natural fracture system is a fractal system, and an actual model can be built up by means of fractal theory. Seismic channel is a chaos of reflection sequence, its fractal ( D ) refects the degree of complexness of the reflection sequence, the more stable the sequence; the larger the value D ; and the more well developed the fracture system. This method has been applied to the Nanyishan oil field in Qaidam basin, and the fracturing zone predicted has been certified by drilling and observation of cores from wells. In the application of this method, geologic background should be studied in combination with dynamic data, such as logging, drilling, and production logging etc. to analyze the geologic characteristics, to make clear other factors affecting the seismic wave speed, frequency and amplitudes and to assure that the abnormalities picking up are due to the presence of fracturing zone. Prediction should be combined with the fracture showing in drilling; and quantitative interpretation of logging data; and the seismic channel near well should be calibrated with the logging data to diminish the non uniqueness of the seismic signals, and to increase the prediction accuracy of the fracture prediction. Subject