New Algorithm to Quantify Well Productivity of Wells in Solution Gas Drive Reservoirs with More Than One Permeability Circular Region

Abstract

Oil well Inflow Performance Relationship (IPR) defines the reservoir potential to deliver fluid from reservoir into the wellbore. The IPR curve plays an important role to ensure the feasibility of drilling wells at a lower scale and the field development at a larger scale. Most of the available existing IPR correlations were developed for homogenous reservoirs. In reality, the reservoir seldom shows homogenous behavior. Using incorrect IPR correlation for a particular reservoir may induce uncertainty in the estimated flow rate for a given drawdown. This may affect the process of decision making especially in large-scale field development projects. Even though many analytical IPR correlations are available in the literature, but they are either complex or require unknown input parameters. This study focuses on the effect of composite reservoirs (more than one permeability regions/rings) behavior on IPR for solution-gas drive oil reservoirs. The main objective of this study is to develop a new empirical IPR correlation for composite reservoirs. Many investigators have developed correlations for a solutions gas drive reservoir for specific well/reservoir types such as dual permeability, multilateral, etc. where they fit well for a specific reservoir behavior and might be unrealistic for different reservoir types. The inflow performance relationships for composite reservoir with more than one reservoir properties regions (rings) are not yet investigated. Hence, there is a need to develop such correlation. The accuracy of the new IPR model is also quantified showing acceptable error as compared to other existing correlations. The new generated empirical IPR equation can be used to predict the performance of vertical wells in a solution gas drive composite reservoir with more than one heterogeneous regions (rings). This simple IPR correlation would provide petroleum engineers a simple and accurate tool for predicting the well inflow performance of composite reservoirs.