单相流数值试井参数调节方法研究

Parameter Adjustment for the Numerical Well Test of Single Phase

利用UST数值试井软件研究了单相油数值试井的参数调节方法,给出了井储、表皮和粘度等参数对试井曲线形态影响的规律。对于生产井,研究表明,当井储增大时,纯井储段时间被延长,推迟了地下流体流动的时间,在双对数图中表现为直线段和峰值右移,但峰值大小基本不变。当纯井储段向地下渗流过渡时,表皮参数S增大,引起压力导数峰值变大,流动能力降低;进入径向流后,增大S,可使压力与压力导数的距离增大,即可通过表皮调节实测曲线和计算曲线的开口大小。粘度参数μ增大时,恢复段试井曲线形态向右上移动。即流体粘度增大,使地层流动能力降低,井储时间延长,井底压力下降。μ增大,等效于渗透率K减小,所以调节粘度等效于调节渗透率。同时,研究表明数值试井的调参方式等同于解析试井。

The parameter adjustment for the numerical well test of single phase oil is presented in this paper in which the influence of well-bore storage,skin factor and viscosity for the curve shape of numerical well test is studied.For production well,the research shows what following.As the well-bore storage parameter increases,the well-bore storage period is extended,and the occurrence time of the underground flow is delayed.Performance in the double-logarithmic plot,the straight line segment and the peak shifted to the right,but the height of the peak is essentially the same.In the transition segment of well-bore storage to underground flow,when skin factor increases,the peak value of pressure derivative turns to larger,and liquidity reduces.In the period of radial flow,as the skin factor increases,the distance between pressure curve and pressure derivative curve is increased.Therefore the opening size of measured curve and calculated curve can be adjusted through the skin factor.The viscosity parameter increases causing the curve shape of recovery well test shifted to the upper-right.It means that as the fluid viscosity increases,the formation flowability is reduced,the well-bore storage time is extended,and the bottom-hole pressure is dropped.Increase viscosity is equivalent to decrease permeability,so adjust the viscosity is equivalent to adjust the permeability.