基于地震岩石物理的致密砂岩流体预测及研究

Fluid Prediction of Tight Sandstone Based on Seismic Rock Physics

在分析研究区气田储层物性的基础上,利用测井资料,展开以地震岩石物理参数分析、弹性阻抗分析、流体替换以及AVO分析为主的叠前储层预测和流体识别。基于储层的岩石物理特征分析,通过运用弹性阻抗反演理论对研究区的地震资料进行分析研究。实践表明,利用岩石的弹性物理参数能够很好地区分砂岩和泥岩,并且能够确定对储层或含气性参数的敏感性,用弹性波阻抗反演方法可得到较为理想的反演结果,而且提取出的岩性参数能够反映出岩性和流体的特征。与传统的波阻抗反演相比,不同角度的弹性阻抗反演具有丰富的信息含量、高分辨率等特点;此方法达到了定量的程度,而且速度快,使得储层预测和流体识别更具有针对性。

With the increase of petroleum prospecting difficulty and cost, people are having higher demand in geophsics which is an important means of petroleum prospecting, from the early simple structure imterpetation to the present lithology and fluid prediction. Rock physics is the connection between reservior characteristic parameters and seismic data, and is also neccessary for forward and inverse calculation and comptrhensive interptetation, which not only provides knowledge base and necessary data for forward and inversion modeling, but also reduces the uncertainty of inversion problem. Elastic impedance inversion has good fidelity and much information, the litholog- ical parameters reflecting lithologh and fluids can be figured out , such as P- wave and S -wave impedance, and P - wave and S - wave velocity ratio and Poission ratio and like forth. The study area is located in H gas field. The reservoir gas - bearing sand is close to shale in density, wave velocity and elastic impedance. Based on well logging data, combined with rock physics analysis, elastic impedance analysis and AVO analysis, the studies on reservoir prediction and fluid identification in the gas field are carried out.