Generalized inflow performance relationships for horizontal gas wells

The analytical inflow performance relationships (IPRs) of horizontal gas wells are presented in this paper for different reservoir boundary conditions. Even though reservoir simulation models (numerical models) may give more flexibility and detailed results of oil and gas production, analytical models are commonly used in the field for quick, practical and reasonable estimation of well performance. The analytical models are especially attractive when working on single well design and performance optimization. Similar to vertical well models, the analytical models for horizontal wells are developed for specific conditions. The IPR equations for horizontal gas wells are categorized into three boundary conditions; constant boundary pressure (steady-state flow condition), no-flow boundary (pseudo-steady-state flow condition), infinite acting reservoir (transient flow condition). For each condition, the IPR equations of horizontal gas wells are presented and the limitation and appropriate application are discussed carefully. Moreover, this paper discusses the effect of critical parameters such as permeability anisotropy, wellbore length, non-Darcy flow and near wellbore formation damage on the inflow performance of horizontal gas wells. These equations provide the reservoir and production engineers with an invaluable tool in well structure design, development plan, and their daily practice dealing with horizontal wells.