琼东南盆地凝析气井产能评价方法研究

Methods Evaluating Productivity of Condensate Gas Wells, Qiongdongnan Basin

通过研究发现目前气井产能的评价方法存在一定局限性。对于凝析气井、高温高压气井、产水气井等往往存在着二项式产能方程异常的情况,甚至很多常规气井也会出现产能方程异常的情况。产能方程出现异常的原因错综复杂,但是归根结底受到两个主要因素的制约,其一为井底流压;其二为产能方程的指数m。基于前人的研究,以流体渗流的基本理论推导出气井表皮系数引起的附加压降计算公式,以此附加压降为基准,以提出的产能方程为依据对测试井底流压产生的误差进行修正。同时基于卡佳霍夫提出的雷诺数,创新提出紊流影响因子λ,依据实际气田紊流影响因子与产能方程m值的关系回归出相关方程,实际应用中可以方便的使用λ计算出产能方程指数m。通过实际数据进行检验,证实此方法是科学合理的。

It is found that all methods to evaluate the deliverability of gas wells have their own limitations. The binomial productivity equation, which is especially used to evaluate condensate, high temperature and high pressure, and water-producing gas wells,emerges abnormal. Even for most conventional wells, the productivity equation is also unusually. The reasons for abnormality are complicated. However, the fundamental ones are downhole flowing pressure and an exponent in productivity equation of m. Based onprevious study, one formula to calculate additional pressure drop caused by skin factor is inferred from fluid percolation; and some errors in a downhole flowing pressure test are amended by reference of the additional pressure drop and by evidence of the productivity equation. Meanwhile, based on the Reynolds number, the influencing factor of turbulence of d according to λth is presented. And a relevant equation is regressee relationship between be easily calculated by adopting λ and m. In fact, m canthod is scientific and reasonable.λ. It is proven that this method is scientific and reasonable.