Abstract

Choke management is a crucial component of the production life cycle for oil and gas wells and is especially a significant topic in the realm of unconventional reservoirs. A comprehensive understanding and modeling of choke management typically involves various bottomhole drawdown pathways. However, there has been limited numerical research on choke management in fractured reservoirs. In this study, we analyze the effects of choke management on shale gas well performance using an embedded discrete fracture model (EDFM). The effective fracture geometries and other uncertainties are automatically calibrated by EDFM-AI (artificial intelligence) using real production data as model constraint. Additionally, this research introduces a new method for modeling the effects of fracture closure on the long-term estimated ultimate recovery (EUR). We investigated the sensitivity of 9 different choke strategies, each associated with unique fracture closure levels. The key findings reveal that an optimal bottomhole pressure (BHP) drawdown strategy can yield 10.2% higher 20-year EUR than the EUR predicted from history matched model, reaching 0.195 trillion cubic meters. Although some aggressive strategies initially produce more gas, it is surpassed by several conservative strategies at various production times. The proposed model is robust and consistent, making it suitable for analyzing other shale gas plays and extending to three-phase shale oil reservoirs.

Introduction

Numerical simulation of choke management is extremely challenging in unconventional reservoir settings. In unconventional horizontal wells, hydraulic fractures are artificially created using proppants to open the fracture (Ellafi et al., 2020). As bottomhole pressure decreases to enable hydrocarbon flow, proppants can become crushed or embedded into the rock matrix (Wijaya and Sheng, 2020). A conservative bottomhole pressure (BHP) decline rate minimizes proppant conductivity loss during the production period (Bagci and Stolyarov, 2019), while an aggressive strategy compromises proppant integrity, leading to severe fracture closure (Tompkin et al., 2016). Therefore, an optimal choke management strategy exists that will optimize the well performance in the long term.

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