【摘要】 柴达木盆地三湖地区北斜坡第四系生物气区是中国最大的生物气区,上第三系为天然气勘探潜力区.第四系地层为弱成岩的疏松砂泥岩薄互层.在以2D地震为主的三湖地区北斜坡预测岩性气藏,利用叠后波阻抗反演及叠前AVO反演预测含气分布难度很大.而综合地质、测井、地震、生产测试等多学科资料,通过对地震道的岩石物理参数进行随机模拟,获得对含气异常比较敏感的地下岩石物理属性体,并分析最敏感的岩石物理属性产气、产水的阈值区间以建立气水识别模式,再利用气水识别模式对岩石物理属性三维模型进行流体置换,最终得到可能的关于生物气藏的三维空间分布特征.利用本文的方法成功预测和落实了上第三系新领域的风险探井.钻探实效表明,该方法适用性强,可以在很大程度上降低天然气藏预测的多解性和不确定性,为进一步优选有利钻探区带、提出可供钻探的目标与井位、缓解该区储量不足的矛盾提供有力的技术支撑.更多还原

【Abstract】 The Quaternary biogenetic gas province in Sanhu area,at northern slope of Qaidam basin,is the largest biogenetic gas province in China.Natural gas exploration potential replacement zone lies in the upper Tertiary stratum.And the Quaternary stratum of which is primarily composed by weak diagenesised sequences of thin and alternative beds of unconsolidated sandstone and claystone.However,it is difficult to evaluate the distribute characteristics of gas simply by post-stack acoustic impedance inversion and pre-stack AVO inversion with respect to predict lithologic gas reservoir at the edge and corner of the favorable slope in the 2D seismic-based Northern Sanhu slope.In order to get a better understanding about the potential 3D and spatial distribution characteristics of the bio- gas reservoir,this article originally puts forward the method of seismic rock physics stochastic simulation based on Swave model.By this the underground bodies of properties of rock physics sensitive to the gas-bearing abnormalities are obtained,based on the geology,well logging,seismic,production and dynamic data to start.By combine analysis of threshold interval of gas and water production,the most sensitive properties of rock physics,we establish gas-water recognition pattern and further conduct fluid replacement for three-dimensional model on properties of rock physics.Therefore the potential 3D and spatial distribution characteristics of the bio-gas reservoir can be obtained. The risk exploration Well(TNSHl) in the new field of the upper Tertiary stratum has been predicted and verified successfully.Drilled practical results have indicated that non-unique solutions and uncertainty of predicting biogas can be reduced to great extent by this method,providing strong technical support for further optimization of favorable drilling zone,for making available target and well to drill and for alleviating the problem of insufficient reserves in this region,suggesting strong applicability of this technique.更多还原