利用密度差值识别和预测莺歌海盆地高温高压气藏

多年来，对于常规气藏的地震识别和预测已经取得大量的研究成果,且总结了多项有效技术。然而,针对莺歌海盆地东方区高温高压气藏地震预测的应用试验表明,常规的高温高压岩石物理分析、AVO分析以及叠前、叠后波阻抗反演和弹性参数交会等含气性检测方法均无法区分研究区目标层段的气层和非气层。为此,研究并提出了一种密度差值气层识别新方法,利用计算密度(与研究区密度测井和中子测井信息有关)与测井实测密度之间的差值实现气层和非气层的有效分离,再通过叠前反演得到密度差值反演剖面,实现高温高压含气储层中有效气层的识别和预测。实际应用效果证实了该方法的有效性和实用性。

Amount of achievements have been obtained in the research of seismic identification and prediction of gasfields under conventional conditions.However,the seismic prediction tests of high-temperature and high-pressure (HTHP) gasfield in the Dongfang District of Yinggehai Basin show that the conventional seismic detection methods,such as HTHP rock physics,AVO analysis,prestack/poststack impedance inversion and crossplot of elastic parameters cannot identify the gas and non-gas layers in the area.Thus,we propose a new method to identify and predict HTHP gas layers based on the information of density difference in this paper.Firstly,the gas-layers and non-gas-layers are separated by the difference of calculated density (which is related to density log and neutron log) and measured density.Then,the density difference inversion profile is obtained by prestack inversion,which realizes the valid gas layer identification and prediction.The application results of real data verify the effectiveness and practicability of this method.