Title: Assessing the influence of key parameters on an iterative ensemble-based method

Authors: Ricardo Vasconcellos Soares; Célio Maschio; Denis José Schiozer

Addresses: Departamento de Energia, Faculdade de Engenharia Mecânica, Universidade Estadual de Campinas – Unicamp, R. Mendeleyev 200, CEP 13083-970, Campinas, São Paulo, Brazil ' Departamento de Energia, Faculdade de Engenharia Mecânica, Universidade Estadual de Campinas – Unicamp, R. Mendeleyev 200, CEP 13083-970, Campinas, São Paulo, Brazil ' Departamento de Energia, Faculdade de Engenharia Mecânica, Universidade Estadual de Campinas – Unicamp, R. Mendeleyev 200, CEP 13083-970, Campinas, São Paulo, Brazil

Abstract: Ensemble-based methods generate interesting results regarding history-matching processes. However, there are several parameters that can have a large impact on the final response of the process. Therefore, this work presents a comprehensive study of the following parameters of an ensemble-based method, the ES-MDA: different petrophysical images in the initial ensemble, inflation factor (α), measurement error (CD) and truncated singular value during the matrix inversion process (TSV); aiming to understand how each parameter affects data match, uncertainty reduction, and production forecast. Results showed that different initial ensembles have a major impact when using a small number of models, and minor effects for a large number of models. Inflation factors and CD have a high impact on the whole process (data match, uncertainty reduction, and production forecast), and TSV has a minor impact on the process. Finally, careful analysis of these parameters and further research is required to obtain better results. [Received: December 15, 2018; Accepted: June 17, 2019]

Keywords: history matching; ensemble smoother with multiple data assimilation; ES-MDA; localisation; covariance inflation; truncated singular value; TSV; measurement error; initial ensemble.

DOI: 10.1504/IJOGCT.2020.111155

International Journal of Oil, Gas and Coal Technology, 2020 Vol.25 No.4, pp.438 - 475

Received: 15 Dec 2018
Accepted: 17 Jun 2019

Published online: 07 May 2020 *

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