基于数值模型的气井现代产量递减分析及动态预测

发布时间：2018-11-05 17:38

【摘要】：传统的气井生产动态预测方法常采用拟稳态产能方程结合物质平衡方程来进行,由于低渗、致密储层流动很难达到拟稳态,预测结果可能存在较大误差。现代产量递减分析技术已成为单井动态预测的新技术,但还停留在解析模型阶段,通常采用叠加原理进行全程历史拟合。由于气井生产阶段产量波动大、流动阶段多,历史拟合计算周期长,解析法难以满足现场需求。针对上述问题,以垂直压裂井为例,建立了不稳定渗流数学模型,采用混合有限元方法获得了定产降压、定压降产和变产变压等3种生产模式的数值解。并根据定产降压解绘制了现代产量递减分析曲线,变产变压解进行全程历史拟合以及先定产降压、后定压降产的组合进行气井生产动态预测。模型结果与Topaze商用软件的计算结果一致,且数值模型的全程历史拟合速度具有明显优势,与传统生产动态预测方法的结果对比以及现场实例分析结果表明,新模型结果准确且方法实用、可靠。
[Abstract]:The traditional prediction method of gas well production performance is usually carried out by quasi-steady-state productivity equation combined with material balance equation. Due to low permeability, the flow of tight reservoir is difficult to achieve quasi-steady state, and there may be large errors in the prediction results. Modern production decline analysis technology has become a new technique for single well dynamic prediction, but it is still in the stage of analytical model, and the superposition principle is usually used to fit the whole history. Because the production of gas wells fluctuates greatly, the flow stage is many, and the period of historical fitting calculation is long, the analytical method is difficult to meet the field demand. Taking vertical fracturing well as an example, the mathematical model of unstable percolation is established, and the numerical solutions of three production modes, i.e. constant production and pressure drop and variable production and variable pressure, are obtained by using mixed finite element method. The analysis curve of modern production decline is plotted according to the solution of constant production and pressure, and the whole history fitting is carried out by changing production and changing pressure, and the production performance of gas well is predicted by the combination of fixed production and lower pressure, and then constant pressure drop to predict the production performance of gas well. The results of the model are consistent with those of the Topaze commercial software, and the whole course historical fitting speed of the numerical model has obvious advantages. The comparison with the results of the traditional production dynamic prediction method and the field analysis shows that, The results of the new model are accurate, practical and reliable.
【作者单位】：中国石油勘探开发研究院气田开发研究所;中国石油集团川庆钻探工程有限公司长庆井下技术作业公司;低渗透油气田勘探开发国家工程实验室;
【基金】：国家重大科技专项(2011ZX05013-002)资助
【分类号】：TE328

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