论文部分内容阅读
南卡罗纳的Blake Ridge海的海洋地震数据和测井资料表明,含天然气水合物的沉积物覆盖于含游离气的沉积层之上导致了明显的海底地震模拟反射体(BSRs)。本文将一个理论上的岩石-物理模型应用到该区实际的2D地震数据中来计算游离气和天然气水合物的饱和度。把高孔隙度的海洋沉积物模拟成一个粒状体系。在该体系中,弹性波速与下列因素有关:孔隙度、有效压力、矿物、孔隙充填物的弹性特征以及孔隙中的水、气和天然气水合物的饱和度等。为了将理论模型应用到实际的地震资料中去,首先要利用叠加速度分析获得层速度;其次,除了孔隙度、水、气和天然气水合物的饱和度以外的输入参数均应由地质资料获得。为了利用层间速度估算孔隙度和饱和度,要先假设整个沉积物不含游离气或天然气水合物,再利用岩石物理模型直接由层速度得到孔隙度。这样得到的孔隙度剖面图在含有游离气或天然气水合物的地方存在异常(和在不含气或气水合物的沉积物中获得的典型的孔隙度剖面相对比)。在含水合物的区域孔隙度估计不足,而在含游离气的区域孔隙度估计过高,通过从有异常的孔隙度剖面中减去无气或水合物的典型孔隙度剖面计算出剩余孔隙度。然后,在模型中引入气或天然气水合物的饱和度来消除异常。于是,得到了想要的2D饱和度图。这样获得?
Marine seismic data and log data from the Blake Ridge Sea, South Carolina, indicate that deposits of gas hydrates overlying free gas-bearing sediments resulted in overt submarine seismic reflection simulations (BSRs). In this paper, a theoretical rock-physics model is applied to the actual 2D seismic data in this area to calculate the saturation of free gas and gas hydrate. Modeling high-porosity marine sediments into a granular system. In this system, the elastic wave velocity is related to the following factors: porosity, effective pressure, minerals, the elastic character of the pore filling, and the saturation of water, gas and gas hydrates in the pores. In order to apply the theoretical model to the actual seismic data, we first obtain the velocity of the layer by the superposition velocity analysis. Secondly, the input parameters other than the porosity, saturation of water, gas and gas hydrate should be obtained from geological data. In order to estimate the porosity and saturation using interlaminar velocity, we first assume that the entire sediment does not contain free gas or gas hydrate, and then use the petrophysical model to obtain the porosity directly from the layer velocity. The porosity profiles thus obtained present anomalies where free gas or gas hydrates are present (as opposed to the typical porosity profiles obtained in deposits that are free from gas or hydrate). Estimates of porosity in regions containing hydrates are inadequate, while estimates of porosity in regions containing free gas are too high, and residual porosity is calculated from the typical porosity profile by subtracting airless or hydrate from anomalous porosity profile . Then, the saturation of gas or gas hydrate is introduced into the model to eliminate the anomaly. Thus, the desired 2D saturation map was obtained. So obtained?