春光油田储层砂岩地震岩石物理模型构建及其应用

The Establishment of Seismic Rock Physics Model of Reservoir Sandstone in Chunguang Oilfield and lts Application

地震岩石物理模型是分析储层岩石地震弹性性质变化规律及烃类预测的重要工具。现有方法在构建岩石物理模型时较少考虑储层岩石复杂孔隙结构特征，从而造成预测结果存在一定误差。在实验室内对新疆车排子地区春光油田沙湾组储层砂岩样品进行了系统地震岩石物理试验，在确定储层砂岩中不同孔隙类型组成的条件下，基于非接触模型，综合考虑储层砂岩孔隙度以及孔隙形状对于干燥岩石骨架弹性性质的影响，并利用试验结果对模型参数进行标定，进而建立表征目标储层岩石骨架地震弹性性质的岩石物理模型，模型结果与试验结果符合良好。依据试验及模型结果，利用喷射流作用模型替代传统Gassmann方程进行流体替换，能够更好地对流体饱和砂岩样品超声频率试验结果进行解释。

Seismic rock physics model was an important tool for analyzing the rules of seismic elastic variation of reservoir rock and the prediction of hydrocarbon. The existing methods seldom considered the complex pore structure characteristics of reservoir rock when the rock physical model was established, which resulted in some errors in the prediction results. Systematical rock physics experiments were conducted on the sandstone samples of Shawan Formation of Chunguang Oilfield in Chepaizi Area of Xinjiang Province. After determining the pore system and concentration, the non-interaction approximation （NIA） was used to analyze the effects of porosity, pore shape and the concentration of micro-crack to the elastic properties of the dry frame of sandstone samples. The test results were used for calibrating the model parameters. Furthermore, a rock physical model was established to characterize the seismic elasticity of the rock skeleton of the target reservoir. The results of the model were in good agreement with the experimental results. According to the experimental results and model results, the jet flow model is used to replace the traditional Gassmann Equation for fluid replacement, which can better explain the ultrasonic frequency test results of fluid saturated sandstone samples.