The knowledge of well productivity is crucial in well performance evaluation, well design, and addressing and resolving production problems. The inflow performance relationship (IPR) curve is the plot of flowing bottom-hole pressures versus the oil/gas production rates at that pressure values. It is used as a tool to evaluate the productivity of the well, and it can be predicted using production tests or empirical correlations. Many models were previously developed for horizontal wells in gas reservoirs; however, very few models considered the presence of fractures. This study introduces a new robust model to predict the IPR curve for hydraulically fractured horizontal wells in gas reservoirs using a single-point flow test.
A single-well reservoir model was built using CMG Builder to generate the production data, and many reservoir and fracture parameters were changed in the model to cover a wide range of data. Then, the effective parameters were determined by plotting the data in the dimensionless IPR form. Afterward, the data was divided into two portions; 70% for developing the model and 30% for validation. The model was developed using non-linear regression, then validated and compared with previous models using different statistical parameters such as average absolute percentage error, R-square, variance, and standard deviation.
The findings of this study showed that the dimensionless IPR curve is only affected by the reservoir permeability anisotropy and has a weak function of other fracture parameters such as the number of fractures, fracture conductivity, fracture half-length, and fracture height. The developed model showed high accuracy in estimating gas production rates at different bottom-hole pressure values with an R-squared of 0.998 and an average absolute error of only 1.54%. With the new model, only one point of flow test is required to plot the IPR curve.
