Evaluation of Weirs Calculation to Estimate Well Capacity: a Numerical Study

Abstract

To assess a two-phase well capacity in early well testing stage, James Lip Pressure for horizontal discharge is generally applied. The objective of the measurement is to calculate total mass flow rate and enthalpy in order to estimate well capacity. During measurement, two-phase fluid from well is directed horizontally to silencer (atmospheric separator) and water flow rate measured by weir. Simplified weir formula is commonly used for field application rather than the original equation proposed by Kindsvater and Carter (1957). Different equations to calculate water flow rates will lead to different result, therefore it affects calculated total mass flow and enthalpy which represent well capacity. How significant simplified weir calculation for well capacity estimation and comparison of water flow rate calculation between simplified weir calculation and original weir calculation are compared. The result showed, calculation using simplified equation for trapezoidal weir has the biggest error compared to other simplified weir equations, while simplified equation for V-notch has the smallest error.