A novel well-testing model to analyze production distribution of multi-stage fractured horizontal well

Abstract

The sharp decline in oil or gas production has been observed in many multi-fractured horizontal wells (MFHW) within only one or two years’ development. How to determine production rate distribution of MFHW becomes significant for enhancing hydrocarbon productivity. However, the effect of non-uniform production distribution of horizontal sections and fractures on pressure-transient response are hardly considered for the available well-testing models of MFHW, leading to erroneous interpretation results.The aim of this work is to present a novel approach to investigate the non-uniform production distribution along horizontal wellbore in a relatively economical way. An analytical model was developed to better characterize flow in fractures and horizontal wellbore. To better calculate the pressure drops in hydraulic fractures, we modeled the fluid flow in fractures with finite conductivity by considering variable-mass-linear flow for fluid far from wellbore and radial flow for fluid near wellbore. Meanwhile, horizontal wellbore was divided into multiple horizontal sections, and each segment is considered as a cylindrical source. As a result, an analytical pressure solution was developed. The analytical solution was further compared with numerical model in Saphir to verify the accuracy. A new horizontal line before pseudo-radial flow was observed (the second radial flow)) on pressure-derivative curves. It would lead to incorrect interpretation results of parameters if the new regime is regarded as the pseudo-radial flow.