叠前弹性参数反演在南海工区的应用研究

Application of pre-stack elastic parameter inversion in South China Sea

随着油气勘探难度不断增加,叠前弹性参数反演在油气勘探领域已逐渐成为一种有效的储层预测方法.该方法以Zoeppritz方程为基础,相较于叠后反演,叠前数据保留了大量与炮检距相关信息,在精度上有了较大的提升.本文从叠前AVO反演出发,利用纵横波联合反演方法对纵横波速度与密度三参数进行反演,并在模型和工区进行测试及应用.再利用弹性参数对岩石以及岩石填充物的不同敏感性进行储层预测.结果表明,叠前反演分辨率高,对储层的刻画明晰,且反演结果与井吻合度高.将纵横波速度的低速区与低密度区结合分析来预测有利储层的位置,并用实际测井资料进行验证,证明了该方法在储层预测中的有效性和稳定性.

Prestack elastic parameter inversion has gradually became an effective reservoir prediction method in the field of oil and gas exploration. This method takes Zoeppritz equation as the core, uses pre-stack data to retain a large amount of information which is related to offset, and improves the accuracy greatly compared with post-stack inversion. Then, the different sensitivity of elastic parameters to rocks and rock fillers is used to achieve the purpose of reservoir prediction. Starting from pre-stack AVO inversion, this paper uses the method that joint PP and PS wave inversion to invert three parameters of PP and PS wave velocity and density. After getting better results in model test, it is applied to the actual work area of South China Sea. The inversion results are in good agreement with well data, which shows that the method is reliable. Then combining the low-velocity area of P-S wave velocity and low-density area we are able to make sure the location of reservoir. Finally, we utilize the well data to verify the result, which proves the feasibility of this method in reservoir prediction.