Primary Depletion Characterization with No Flow Boundaries Drainage Concept

Abstract

Abstract In unconventional reservoirs, spacing and stacking directly influence the hydrocarbon resources available to be drained by a given lateral. Hypothetically, these available resources, rock properties and stimulation effectiveness will drive the well performance (i.e., Estimated Ultimate Recovery (EUR)). Characterization of the effectively contacted volume is an important element in understanding the well performance and the depletion efficiency of the intended development. This paper will present a simple but novel way of characterizing a well's drainage volume and demonstrates how this characterization can be applied to improve the understanding of expected well recovery, primary depletion efficiency (i.e., recovery factor), and their relationship with petrophysics and geology. The methodology is proposed as a method to help lead to optimum development and resource economic value for the operator. The proposed method uses the concept of no flow boundaries driven by frac geometry established between wells to define a drainage polygon surrounding neighboring laterals. Incorporating supplementary datasets allows further characterization (i.e., well-log to obtain fluid-in-place distribution). The method provides insights which can be tied back to the well performance. For example, the method shows the importance of geology and petrophysics, reflected through the Original Oil in Place (OOIP) within the drainage volume, driving the well's EUR and recovery factor. Significance/Novelty: Improved reservoir drainage volume and well performance characterization can significantly impact the optimum development plan, maximizing both the exploitation efficiency and value for operators.