波形差异分析技术在气田高产气区预测中的应用

Analysis of Waveform Differences in High Gas Zone of Daniudi Gas Field for Prediction

针对大牛地气田含气层段多、砂体非均质性强、横向变化快、波阻抗差异不突出的问题,在地层格架划分的基础上,结合生产井的生产信息,对储层进行波形差异分析,结果表明,不同类产层所对应的井旁道质心、均值、方差、变方差的中心、概率及特征值有一定差异,但敏感度不够。为得到含气性敏感度更高的地震波形参数,对地震波形敏感信息进行分析与重构,构建出7个新的波形差异参数,建立不同产能储层与地震波形的对应关系;在此基础上,反演出目的产层的波形差异数据体;结合沉积相等地质信息对波形差异数据体进行综合解释,得到目的产层的高产气区的预测图;利用生产井及新投产井对预测结果进行分析,总预测符合率达86%。

In Daniudi gas field there are many gas bearing segments, and the sand bodies are highly heterogeneous with great lateral variations, so the differences of the wave impedance are indistinct. Based on the stratigraphic framework, the seismic waveform differences of the reservoir are analyzed according to the production information of wells. There are some differences in the center, probability, and characteristic value of centroid, mean, variance and varying variance for the seismic waves from nearby wells between different production layers, but the sensibility is not enough. In order to obtain seismic waveform parameters of gas bearing formation with higher sensitivity, the seismic waveform sensitive formation is analyzed and reconstructed, and seven waveform parameters are obtained. By analysis and reconstruction of the sensitive information, the corresponding relationship among reservoirs of different productivity and seismic waves is established, and the data of waveform differences are obtained by inversion for the target stratum with this relationship. Combined with geological information, sedimentary facies etc. the waveform difference data are interpreted, and the high gas area layer prediction diagram of the target stratum is obtained. With the data of production wells and new production wells in this area, the prediction results are analyzed, and the total prediction agreement rate reaches 86%.