A model of production data analysis for horizontal wells

The production data analysis is one of hot spots of reservoir engineering recently, which combines conventional reservoir engineering analysis and modern well test analysis. Based on the theory of transient porous flow, the analysis provides a mathematical model, which not only reasonably predicts the production decline of oil or gas wells but also effectively evaluates the physical properties of reservoirs. Theoretical charts of Agarwal-Gardner production decline curves and derivative curves for common horizontal wells are presented by solving the transient 3D porous flow in the bounded reservoir. The Agarwal-Gardner curves can be divided into two stages: the derivatives are dispersed in the early transient decline stage and drawn to Arps harmonious decline in the late pseudo-steady state stage. The influence of vertical location of horizontal wells on production decline in the mid-long term is negligible in a homogenous reservoir. A field example illustrates that, given production data, the results in this article can be directly used to evaluate the reservoir characteristics and effectively forecast the long-term productivity for horizontal wells.