利用抽汲井液面恢复资料解释双孔介质油藏地层参数

Interpretation of formation parameters using liquid level build-up data of swabbing well in double porous media reservoir

非自喷井的抽汲求产是一个很复杂的间歇生产过程。为了不影响抽汲井的产量,利用液面检测仪对抽汲井停产时获取液面恢复数据,并利用相关数据对地层参数进行解释计算,这种技术无疑是今后求取地层参数的主要方向。文中针对双重孔隙介质圆形封闭油藏建立了地层中心一口抽汲井液面恢复的渗流模型,在考虑井筒储集效应和表皮系数的情况下,应用拉普拉斯变换和贝塞尔函数理论对定解问题求解,得到了模型在拉普拉斯空间的精确解,并对曲线图版及拟合过程进行分析。利用曲线图版拟合可以解释原始地层压力,对不关井试井有很好的指导意义,从而也扩大了其应用范围。

Swabbing for acquiring production of unflowing well is a complex intermission producing process. In order not to influence the production rate, using the fluid level detector, this paper acquires the liquid level build-up data of swabbing well when it stops working, then, it calculates the formation parameters using these data. This technology undoubtedly plays an important role in calculating formation parameters. The flow mathematic model of liquid level build-up data of swabbing well in double porous media and circular sealed reservoir is built up under considering the wellbore effect and skin factor. The exact solutions of non- homogeneous equation in Laplace space of the model are acquired by using theory of Laplace transform and Bessel function and the chart of type curve and the matching of type curve are analyzed. Initial formation pressure can be calculated by the method of type curve matching, which has a good guiding for well testing without shut-in, expanding the application range of this method.