计算气井井底压力的新方法

在根据气井井口压力计算井底压力的方法中,平均温度、平均偏差系数计算方法把全井筒的温度,天然气偏差系数视为常数,从理论上来讲不够精确,而按Cullender-Smith方法计算时,是用简化梯形积分即辛卜生积分,比较繁琐。由于手算时,每次都要计算各种参数。文章从纯气柱井底压力的计算公式出发,严格地推导出一种新的表达式,并对式中积分给出精确的解析解,大大简化了计算步骤。

A New Method for Calculation of Gas Well Bottom-hole Pressure

During calculating the bottom-hole pressure of gas well based on the wellhead pressure, the entire wellbore temperature and gas deviation factor were considered as constant, so average temperature and average variation coefficient were used as calculation parameters, but which is not precise enough in theory. While calculation with Cullender-Smith method is to use simplified trapezoidal integration, the calculation is more complicated because every parameters must be calculated. In this paper, starting from the calculation formula of pure gas column bottom-hole pressure, a new expression was strictly derived out, and the exact analytical solution was gained, which can greatly simplify the calculation procedure.