Crisman Annual Report 2009 - Harold Vance Department of ...

Investigation of Hybrid Steam-Solvent Processes to Increase Efficiency of Thermal
Oil Recovery Methods
Objectives
Steam assisted gravity drainage (SAGD) has received
considerable attention as a proven technique to
recover heavy oil and bitumen which are immobile
at reservoir conditions. The main drawbacks of this
process are high energy intensity (steam generation
requirements) and environmental issues.
The addition of light hydrocarbon solvents to steam is
the simplest and most important approach to improve
SAGD process and reduce potential problems. Main
benefits possibly obtained by a hybrid steam solvent
process include: reduced Steam Oil Ratio, reduced
environmental impact, increased recovery via
reduced S or
, reduced capital to startup and enhanced
well productivity. Principal challenges are the choice
of solvent and concentration and operating strategy.
Our main research objective is to reduce energy
intensity of SAGD process by using solvents
and investigate the effect of different operating
strategies. Key tasks are to evaluate the effect on
oil recovery of the following:
» Solvents, (e.g., butane, hexane and condensates)
» Solvent concentration
» Injection types (e.g., cyclic steam solvent injection)
Fig. 1. Simulation results of oil recovery.
with increasing concentration. The aluminum 2D
cylindrical model is under construction. The sandmix
space has an inner radius of 4 in, 1-in thickness, and
10-in height, and will be lined with insulating Teflon
layers (Fig. 2). The experimental set up is shown
in Fig. 3.
Approach
Experiments will be carried out in a scaled 2D
cylindrical cell to evaluate the effect of steam-solvent
processes. Pujol and Boberg’s scaling method has
been used to design the model. Advantages of the
cylindrical model are the relatively high pressure
capability without a pressure jacket, the use of inner
thermal insulation, and the ability to conduct gravity
drainage experiments (e.g., VAPEX, SAGD). Oil and
water production, gas composition, and temperature
would be measured and analyzed. Numerical
simulation will be used for parametric studies.
Accomplishments
Compositional reservoir simulation studies of Cold
Lake bitumen were performed to investigate the
effect of solvent type and concentration on recovery
under SAGD at 220°C and 3100 kpa (450 psia)
(Fig. 1). With C5-C7 as solvents, bitumen recovery
increases to about 80% at 20 wt%. C2 and C3
however exist as vapor and act as thermal insulators
at the steam-bitumen interface, reducing recovery
Project Information
1.3.22 Investigation of Hybrid Steam-Solvent Injection to
Increase Efficiency of Thermal Oil Recovery Processes
Related Publications
Nasr T.N., and Ayodele O.R. New Hybrid Steam-Solvent
Processes for the Recovery of Heavy Oil and Bitumen.
Paper SPE 101717, presented at the 2006 International
Petroleum Exhibition and Conference, Abu Dubai, UAE, 5-8
November.
Ayodele, O.R., et al. Laboratory Experimental Testing
and Development of an Efficient Low Pressure ES-SAGD
Process. 2009. J. Cdn Pet. Tech. 48 (9).
Contacts
Daulat Mamora
979.845.2962
daulat.mamora@pe.tamu.edu
Mojtaba Ardali
CRISMAN INSTITUTE
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Crisman Annual Report 2009