须家河组甜点预测经典模式多解性探讨——以大邑地区须家河组三段气藏为例

Study on the Multi-Solutions of the Classical Model for Dessert Prediction in Xujiahe Formation—Taking the Gas Reservoir of the 3rd Member of Xujiahe Formation in Dayi Area as an Example

摘要: 大邑地区须三段储层为超低孔、超低渗的致密储层，前期普遍认为该类储层含气后与围岩波阻抗非常接近，因此在地震剖面上对应一套振幅较弱复合地震反射带。本文针对大邑地区须三段主力产层TX31砂组，通过对典型井精细标定对比分析发现：受裂缝、物性及流体综合影响，相对储层内部的杂乱弱反射，储层的顶部反射发生中断或变弱与储层含气相关性更好。通过正演模拟进一步证实：储层顶部反射的弱振幅为该区须三气藏含气储层地震响应特征。以此为基础利用地震属性对甜点进行预测，进一步指导大邑须三气藏的井位部署及勘探开发工作。

Abstract: The reservoir of the 3rd member Xujiahe Formation in Dayi Area is tight reservoir with ultra-low porosity and permeability. It is generally believed that the impedance of gas-bearing reservoir is very close to the surrounding rock, so a set of weak amplitude reflection zones corresponds to seismic section. For the TX31 sand group, the main producing layer of the 3rd member Xujiahe Formationin Dayi Area, through fine calibration and contrast analysis of typical wells, it is found that: under the comprehensive influence of fracture, physical properties and fluid, compared with the disordered weak reflection inside the reservoir, the interruption or weakening of the top reflection of the reservoir has a better correlation with the gas content of the reservoir. The forward simulation further confirms that the weak amplitude reflected from the top of the reservoir is the seismic response characteristics of the gas reservoir of the 3rd member of Xujiahe Formation. On this basis, the seismic attributes are used to predict the sweetness, which can further guide the well location deployment and exploration and development of the gas reservoir of the 3rd member of Xujiahe Formation.