Solvent-Enhanced Steamdrive: Experiences From the First Field Pilot

Topics: Enhanced recovery Heavy oil/tar sands
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In recent years, the addition of a hydrocarbon condensate to steam operations in heavy-oil and bitumen reservoirs has emerged as potential technology to improve not only oil recovery but also energy efficiency. The idea of solvent addition to a steamdrive process has been extended and applied for the first time in the Peace River area in Canada. There, evidence was obtained of oil uplift in the patterns where solvent was injected. However, piloting this new technology in a brownfield had many challenges, especially when evaluating its main economic factors: production increase and solvent recovery.

Introduction

Vertical-well steamdrive (VSD) is the ­selected process to recover bitumen from the Peace River Bluesky formation. Solvent coinjection has been identified as an economical method to improve the efficiency of this process. In an early phase of the steamdrive, a slug of hydrocarbon condensate (diluent) is coinjected with the steam. The solvent condenses at the cold steam/bitumen interface to form a solvent bank. This bank has the potential to accelerate bitumen production by viscosity reduction and to improve ultimate recovery.

The efficiency of the diluent coinjection in a steamdrive process is expected to be lower than that of liquid addition to steam for enhanced recovery; however, the solvent recovery factors are expected to be much higher. The solvent recovery, therefore, is a key factor in the economic viability of the process. The main objectives of the pilot were to obtain a positive response in bitumen production and accurate quantification of the diluent recovery. An accurate assessment of the bitumen-production increase was not expected because of the small size of the pilot and lack of control patterns; hence, the injection slug size and concentration were designed to obtain a significant and measurable bitumen response.

This article, written by Special Publications Editor Adam Wilson, contains highlights of paper SPE 175414, “Solvent-Enhanced Steamdrive: Experiences From the First Field Pilot in Canada,” by M.L. Verlaan, SPE, and R. Hedden, SPE, Shell Canada; and O. Castellanos Díaz, V. Lastovka, SPE, and C.A. Giraldo Sierra, Shell Chemicals Americas, prepared for the 2015 SPE Kuwait Oil and Gas Show, Mishref, Kuwait, 11–14 October. The paper has not been peer reviewed.
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Solvent-Enhanced Steamdrive: Experiences From the First Field Pilot

15 February 2016

Volume: 68 | Issue: 3