变井筒储集效应下的试井图版研制

A STUDY ON THE WELL TESTING INTERPRETATION CHART FOR THE WELLS WITH VARIABLE WELLBORE STORAGE EFFECT

李治平 赵必荣

Li Zhiping Zhao Birong

西南石油学院

本文在考虑变井筒储集效应下,建立了压降试井数学模型,通过拉普拉斯变换和数值反演方法,研制出了变井筒储集效应下新的压降试井图版。该图版是以tD/βD(无因次时间/无因次衰减系数)为横坐标,以PD(无因次压力)和P’D·tD/βD(P’D为无因次压力导数)为纵坐标,以βDe2S为参数团的一组压力和压力导数曲线的组合图版。它具有不同于Gringnrten图版的许多特点,尤其是早期段曲线不是斜率为1的直线,而是大于45°的一组弧线,这与实际情况十分吻合。该图版使用方便,求参数准确可靠。文中介绍了图版的制作、特点以及使用方法等。

This paper establishes a mathematical model of pressure drawdown test for the wells with variable wellbore storage effect.Applying the Laplace transform and numerical inversion method,a new pressure drawdown welltesting interpretation chart with variable wellbore stotage coefficient is developed,which is a combination chart of pressure and pressure derivative taking βDe2S as the changing perameter,whose abscissa is tD/βD(tD is dimensionless time,βD is dimensionless attenuation factor),whose ordinate is PD(dimensionless pressure) and P’D·tD/βD(P’D is dimensionless pressure derivative).It has many advantages differ from that of Gringarten chart.That the early-time portions in the said chart is not the straight lines with a slope of 1,but a series of arc curves whose dip angles are more than 45° coincides with the real situation.This chart is easy to use,the interpretated parameters are accurate and reliable.The cartographic way,special feature and operating method of the above-mentioned chart are introduced in this paper.

10.3969/j.issn.1000-7393.1994.04.009