Iterative Ensemble Kalman Smoother Applied to History-Matching Coalbed Methane Wells

Abstract

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper URTEC 208291, “Introducing Iterative Ensemble Kalman Smoother to History-Matching Horizontal Coalbed Methane Wells,” by Rubakumar Sankararaj, SPE, and Sylvain Ducroux, SPE, Resoptima, and Dan Kuznetsov, SPE, Arrow Energy, et al. The paper has not been peer reviewed. This study presents the iterative ensemble Kalman smoother applied to a low-permeability coalbed methane (CBM) field in Australia. All wells in the studied reservoir are completed with an artificial lift system and permanent downhole gauges. A forecast study was conducted to validate the history-matched ensemble. The results showed a good match of 12 months of the new production data not used in history matching, which highlights the robust prediction capabilities of the approach. Geology of the Study Area Because of its strategic geologic and geographic situation in Queensland State, the Bowen-Surat area constitutes one of the more economically significant sedimentary provinces of the Australian mainland and one of the world’s major coal and coal-seam-gas-producing regions. This study considers the Q seam from the Late Permian. Although its thickness varies in the basin because of merging and splitting, it is continuous locally, with an approximate thickness of 5–6 m.