基于油井早期产量递减分析的地层参数反演方法

油井投产初期受生产制度影响导致产量不稳定,常规产量递减分析方法并不适用。针对该问题,采用杜哈美原理将油井变产量压力解转化为定产压力解的形式,通过引入物质平衡时间及规整化产量,得到适用于油井早期变产量生产的数据分析方法,并运用数学模型对处理后的数据进行拟合,从而获得储层参数的反演。以大庆油田P1-2井为例,利用日产油及井底流压生产数据,进行单井生产动态定量分析,绘制了规整化产量-物质平衡时间的双对数曲线图版,定量反演解释地层真实物性参数。结果表明,该方法用于分析变产量生产数据后,曲线表现出常规递减图版不稳定流和边界流明显分段的特征。实例应用表明,该方法平均误差小于10%,准确性较高。该研究可为油井早期产能分析提供理论指导。

Formation Parameter Inversion Method Based on Early Production Decline Analysis of Oil Well

In the initial stage of production of oil wells, affected by the production system, the production is unstable, and the conventional production decline analysis method is not applicable. To solve this problem, by means of transforming the variable production pressure solution of oil wells into the constant production pressure solution under Duhamel’s principle, a data analysis method suitable for early variable output production of oil wells is obtained through introducing material balance time and normalized production, and the mathematical model is used to fit the processed data, so as to obtain the inversion of reservoir parameters. Taking Well P1-2 in Daqing Oilfield as an example, the daily oil production and bottom-hole flow pressure production data were used to quantitatively analyze the production dynamics of a single well, and the regularized production-material balance time double logarithmic curve chart was plotted to perform the quantitative inversion interpretation of the real physical parameters of the formation. The results show that after the method is used to analyze the production data of variable output, the curve exhibits the characteristics of unstable flow and distinct segmentation of the boundary flow in the conventional decline plot. The practical application shows that the average error of this method is less than 10%, and the accuracy is high. This study can provide theoretical guidance for the early productivity analysis of oil wells.