A new production decline model for horizontal wells in low-permeability reservoirs

Abstract

Predicting well performance in low-permeability reservoirs has attracted attentions in the last decades. Decline curve analysis is treated as the most convenient and efficient approach to forecast production. However, each single decline model has its own limitations due to the low permeability and porosity. Hence, we cannot directly apply these models in the low-permeability reservoirs, especially the dramatically drop in the early period. In this study, based on the analysis of conventional production decline models and the development characteristics of low-permeability reservoirs, a new production decline model was proposed, which can quickly and accurately predict the future performance of horizontal wells. Three fitting parameters were employed representing the production performance in early, middle and late-life period respectively. A decline exponent parameter of n was also included in the proposed model. Subsequently, the proposed model was validated, and good agreement was obtained with the production data of a low-permeability block in China. The comparison between new method and other models are analyzed in detail, which illustrates that this proposed approach is more flexible and confident. This work can give a useful insight into accurately and efficiently predicting well performance in low-permeability reservoirs.