Analytical Approach for Multi-Phase Production Data Analysis inBoundary-Dominated Flow Using Three-Phase Fluid Properties

摘要

This paper presents a simple yet rigorous model and provides a methodology to analyze production data fromwells exhibiting three-phase flow during the boundary-dominated flow regime.Our model is particularlyapplicable to analyze production data from volatile oil reservoirs,and should replace the less accurate single-phase models commonly used.The methodology will be useful in rate transient analysis and productionforecasting for horizontal wells with multiple fractures in shales.Our analytical model for efficientlyhandling multi-phase flow is an adaptation of existing single-phase models.We introduce new three-phaseparameters,notably fluids properties.We also define three-phase material balance pseudotime and three-phase pseudopressure to linearize governing flow equations.This linearization makes our model applicableto wells with variable rates and flowing pressures.We optimized the saturation-pressure path and furthersuggested an appropriate method to calculate three-phase pseudopressures.We validated the solutionsthrough comparisons with compositional simulation using commercial software;the excellent agreementdemonstrated the accuracy and utility of the analytical solution.We concluded that,during the boundary-dominated flow regime,the saturation-pressure relation given by steady-state path and tank-type model forvolatile oil reservoirs leads to satisfactory results.We also confirmed that our definitions of three-phase fluidproperties are well suited for ultra-low permeability volatile oil reservoirs.The computation time of ourmodel is greatly reduced compared to a numerical approach,and thus the methodology should be attractiveto the industry.Our model is efficient and practical to be applied for production data analysis in ultra-lowpermeability volatile reservoirs with non-negligible water production during the boundary-dominated flowregime.This study extends existing analytical model methodology for volatile oil reservoirs and is relativelyeasy for reservoir engineers to understand.