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近年来 ,四川盆地浅层天然气的勘探开发进入了新阶段 ,储量、产量迅速增长 ,在评价勘探中 ,精细的二、三维地震解释 ,在储层精细描述、储量计算、制订开发方案等方面起着重要作用。浅层天然气的勘探开发实践及地震资料的精细处理解释表明 ,浅层含气砂体地球物理响应特征是解释和标定含气砂体的主要依据 ,其振幅变化为基础的多参数综合分析技术 ,提供了区分砂体含气性方法。在区内当含气砂体的波阻抗小于其上下围岩 ,其顶底界面的反射呈上负下正、(视 )频率较低、振幅较强的特征 ,即含气砂体与上覆地层的波阻抗差越大 ,则反射波波谷的振幅越强 ;与下伏地层的波阻抗差越大 ,则反射波的波峰振幅越强。
In recent years, the exploration and development of shallow natural gas in the Sichuan Basin has entered a new phase with rapid growth in reserves and production. In the evaluation of exploration, detailed two- and three-dimensional seismic interpretation has been carried out in fine reservoir description, reserve calculation and formulation of development plans An important role. The exploration and development practice of shallow natural gas and the elaboration and interpretation of seismic data show that the geophysical response characteristics of shallow gas-bearing sand bodies are the main basis for interpretation and calibration of gas-bearing sand bodies and the multi-parameter comprehensive analysis technique based on the amplitude changes. A method of distinguishing sandbodies from gas is provided. When the wave impedance of gas-bearing sand bodies is smaller than that of the surrounding rock, the top and bottom interface reflections of the gas-bearing sand bodies are positive, negative (low frequency) and strong amplitude, that is, the gas-bearing sand bodies and the overlying The larger the impedance difference of the formation, the stronger the amplitude of the reflected wave trough; the larger the impedance difference with the underlying formation, the stronger the peak amplitude of the reflected wave.