A Proposed Modified Equation for One Phase Steam Geothermal Well

Abstract

Modelling of one phase steam in geothermal well is usually using an equation derived with assumption of incompressible fluid flow. This equation actually is addressed to analyse fluids with small compressibility such as water, whose density change is very small and can be neglected. Previous studies suggested that this equation can be used to analyse steam flow when the velocity is relatively low, about 103 m/s (0.3 Mach number). Based on observation data, velocity of flowing fluid in MBB-3 reached 115 m/s. When the velocity approaches or exceeds 0.3 Mach number (Ma), a good match between model and data observation is difficult to achieve. To achieve a better wellbore steam flow model, we need to develop an equation based of compressible fluids was developed. This modified compressible equation was derived from combination of continuity, momentum, and energy equations. This modified compressible equation as a result from this research was validated with observation data from MBB-3 well of Wayang Windu field, and also compared to model from Cullender and Smith correlation. The result shows that the modified compressible flow model gives better agreement with observation data compared both previous incompressible equation and Cullender and Smith correlation.