深水浊积岩储层定量解释技术及应用

目前深水浊积岩储层定量解释主要是在岩石物理分析基础上采用弹性参数截止值来实现,该方法无法准确描述定量解释存在的不确定性,存在较大的误差.因此,研究形成一种新的深水浊积岩储层定量解释技术,首先基于叠前反演获取弹性参数体,分岩性统计已钻井数据,通过交会分析确定弹性参数对不同岩性的响应范围,并采用随机模拟建立不同岩性的概率分布函数,然后基于贝叶斯分类方法,估算目的层范围内每一种岩性的相对比例,并对概率密度分布函数进行加权,将加权后的概率密度分布函数应用到地震属性体获取岩性概率体,再通过多实现岩相随机模拟得到岩相体.最后,在岩相体约束下通过高斯协模拟获得孔隙度体.实际应用表明,改进的深水浊积岩储层定量解释技术得到的岩性数据具有更加明确的地质含义,并可定量评估岩相预测风险,提高了定量解释精度.

Quantitative interpretation technology and application of Deepwater Turbidite reservoir

At present, the quantitative interpretation of deepwater turbidite reservoir is mainly realized by using the cut-off value of elastic parameters on the basis of petrophysical analysis. This method can not accurately describe the uncertainty of quantitative interpretation, and there is a large error. Therefore, a new quantitative interpretation technology of deep-water turbidite reservoir is formed. Firstly, elastic parameter volume is obtained from prestack inversion, and the drilled data are counted by lithology. Then, the response range of elastic parameters to different lithology is determined by intersection analysis. The probability distribution function of different lithology is established by random simulation. Then, the relative proportion of each lithology within the scope of the target layer is estimated based on Bayesian classification method, and the probability density distribution function is weighted. The weighted probability density distribution function is applied to the seismic attribute volume to obtain the lithologic probability body, and the lithofacies body is obtained by multi realization random simulation of lithofacies. Finally, under the constraints of lithofacies, the porosity bodies are obtained by Gaussian co-simulation. The practical application shows that the lithologic data obtained by the improved quantitative interpretation technology of deep-water turbidite reservoir has a clearer geological meaning, and can quantitatively evaluate the risk of lithofacies prediction, and improve the accuracy of quantitative interpretation.