Title: Mechanistic study of steam assisted gravity drainage in heavy oil naturally fractured reservoirs

Authors: Ali Fattahi; Hamed Akhodzadeh; Mohd Nawi Derahman

Addresses: Faculty Petroleum and Renewable Energy Engineering, Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor Bahru, Malaysia ' Faculty Petroleum and Renewable Energy Engineering, Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor Bahru, Malaysia ' Faculty Petroleum and Renewable Energy Engineering, Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor Bahru, Malaysia

Abstract: While SAGD has been applied in tar sands extensively and its mechanism is well understood, the SAGD mechanism in heavy oil Naturally Fractured Reservoir is yet to be investigated. In this paper, the mechanism of SAGD in NFRs was studied. Results suggest that initial fracture water saturation plays a conspicuous role in production from NFRs, with no preheating requirement. This condition facilitates massive water production, leading to a considerable steam injection and consequently fast steam chamber creation. In oil-wet reservoirs, oil drainage takes place inside the steam chamber. In water-wet media, however, capillary imbibition contributes to oil recovery behind the steam chamber in hot water zone. The index Km/Lm was introduced which combines matrix permeability and size to propose a determining factor for matrix oil drainage rate. The controlling term of Kf Sfwo for the process initiation was proposed, so that higher values of this term imply sooner chamber creation. [Received: June 23, 2016; Accepted: July 20, 2017]

Keywords: fractured reservoirs; heavy oil; SAGD mechanism; enhanced oil recovery.

DOI: 10.1504/IJOGCT.2019.099171

International Journal of Oil, Gas and Coal Technology, 2019 Vol.20 No.4, pp.441 - 462

Received: 23 Jun 2016
Accepted: 20 Feb 2017

Published online: 19 Apr 2019 *

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