Title: An improved algorithm for unknown flow rate history reconstruction with the Haar wavelet transform

Authors: Fuyong Wang

Addresses: Research Institute of Enhanced Oil Recovery, China University of Petroleum (Beijing), No. 18 Fuxue Road, Beijing, 102249, China

Abstract: Flow rate history is the key information for reservoir surveillance and management, but it is not always available in practice due to expensive and unstable metering devices. This paper proposes an improved algorithm of reconstructing flow rate history from down-hole transient pressure data with wavelet transform (WT). The Haar wavelet can effectively identify flow events and distinguish pressure drawdowns from buildups, and the amplitude of WT coefficients of flow event is proportional to the flow rate change. The effects of data noise, wellbore storage and skin on flow event identification were investigated. The improved algorithm can reconstruct the flow rate history when the initial flow rate is unknown, and this improved algorithm was demonstrated with synthetic case studies and field application. [Received: November 25, 2015; Accepted: July 17, 2016]

Keywords: well test; pressure-transient analysis; production history; flow rate; transient pressure; wavelet transform; Haar wavelet; permanent down-hole gauge; PDG.

DOI: 10.1504/IJOGCT.2018.093956

International Journal of Oil, Gas and Coal Technology, 2018 Vol.19 No.1, pp.59 - 82

Received: 30 Nov 2015
Accepted: 17 Jul 2016
Published online: 10 Aug 2018 *

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