Calculate Bottom Hole Pressure with the Cullender and Smith Method

This Excel spreadsheet employs the Cullender and Smith method to calculate Bottom Hole Pressure on a shallow, dry gas well. The bottom hole pressure is simply the pressure at the bottom of an oil-well shaft

Many reservoir engineering calculations require the static bottom hole pressure.  However, this can be difficult to measure experimentally. A number of researchers have developed other techniques to calculate bottom hole pressure from measurements at the wellhead.

The Cullender and Smith (1956) method is generally considered accurate and models the variation of compressibility Z with temperature T and pressure P

This is the Cullender and Smith equation

It needs to be numerically integrated. In the attached spreadsheet, we have simply divided the entire length into four sections and integrated via a simple trapezoidal method.

Download Excel Spreadsheet to Calcualte Bottom Hole Pressure with the Cullender Smith Method