地层等效吸收系数反演

Formation equivalent absorption coefficient inversion

1. 同济大学海洋系,上海200092;2. 石油大学资源系,东营257061;3. 江苏油田计算站,南京210046

Department of Marine Geology and Geophysics, Tongji University, Shanghai 200092

吸收系数是进行储层描述和油气预测时的一个重要参数,它对岩性变化具有很高的灵敏性。结合层位解释结果从地震资料中提取该层位地层吸收系数的空间分布对于提高油藏描述及油气预测精度具有重要作用,并可与其它地震、测井和地质信息相结合直接用于圈定油气分布范围,估算储量。针对根据地震振幅信息直接提取吸收系数的方法所存在的主要困难———反射振幅失真和波形畸变,提出了应用谱模拟来反演地层等效吸收系数的方法。对地层吸收系数的地质意义、表征地层吸收性质的参数以及所用的反演方法进行了介绍,并通过本方法在某油田一区块的应用说明了其有效性和实用性。

Absorption coefficient is an important parameter in the reservoir description and hydrocarbon prediction. It is very sensitive to the variation of lithology. The spatial distribution of formation absorption coefficients which are estimated from horizon interpretation of seismic data plays an important role in improving accuracy of reservoir description and hydrocarbon prediction, and can be used to delineate hydrocarbon distribution and estimate reserves when combines with other seismic data, log, and geologic data. It is difficult to extract absorption coefficients directly from seismic amplitude due to the distortions in amplitude and waveform. To overcome the above-mentioned problems, this paper proposes to inverse formation equivalent absorption coefficients with spectral modeling. The geologic meaning of formation absorption coefficients, the parameters characterized formation absorption properties, and the inversion method used here are presented. The applicability of the method is illustrated with real data.