Production Decline and Numerical Simulation Model Analysis of the Eagle Ford Shale Oil Play

Abstract

Abstract Intrinsic behavior of fluid flow in extremely tight porous media and presence of hydraulically fractured long horizontal wells in shale oil reservoirs imposes different set of challenges for performance prediction. Conventional Arps’ prediction mechanisms are often inadequate to apply for two main reasons among others: transient flow regimes lasting the entire well productive life and short production history for young shales. Low hydrocarbon recovery factors also dominated the prospect. This paper compares and contrasts outcomes of some prediction mechanisms such as Arp's empirical equation in decline curve analysis (DCA), logistic growth analysis (LGA) of oil cumulative production, and numerical simulation model (NSM) analysis. Enhanced oil recovery (EOR) by injection of CO2 gas was also considered. The study accomplishment is to recommend the most appropriate prediction tool that is applicable to hydraulically fractured horizontal wellbores in shale oil reservoirs dominated by transient flow regimes and having relatively short performance history. The outcome of the enhanced oil recovery simulation is significant to determine optimal spacing of producer-injector patterns and optimum drainage areas within and beyond the stimulated reservoir volumes (SRV). Different outcomes were observed for the same well based on the sections or all of data analyzed using DCA. Logistic growth analysis of cumulative production forecasted conservatively similar to Arps’ exponential decline model. The logistic growth model fit quite well on most cumulative production trends especially at the ends of the profile leading to better predictions. Using realistic static and dynamic reservoir properties, NSM fits production histories very closely under constant operational settings, but the forecasted cumulative productions obtained are subjective to the accuracy of reservoir properties. Oil recovery factors from EOR slightly improved primary depletion values when the source reservoir was flooded with CO2 and could extend the well's productive life by 8–10 more years. Process of shale oil performance prediction is not yet uniquely defined and calls for more investigation into diverse ways to perfect it. The options studied are useful in getting volumetric calculations closely accurate. Oil recovery optimization is also the heart of petroleum production, hence useful hint is provided.