Dimethylether-A Promising Solvent for ES-SAGD

摘要

Co-injection of solvent with steam is one of the promising methods to recover bitumen. The major operational cost for these projects is related to steam generation, water treatment and solvent. Propane and butane have shown desirable performance as solvent. In this work, we introduce dimethyether (DME) as an alternative solvent because of its lower cost compared to propane and butane. We evaluate the capability of DME as a solvent for bitumen recovery processes. To investigate the performance of solvents, a series of experiments were conducted using a 2D sand-pack saturated with Athabasca bitumen. In these experiments, co-injection of steam with DME was compared with steam and steam/butane injections. The steam injection was conducted at 1 MPa and solvent concentration of 5 vol. % was tested in solvent/steam co-injection experiments. The cumulative bitumen production and bitumen production rate for each scenario were measured and compared with SAGD. Experimental results revealed that using butane and DME as the additives to steam will improve the bitumen recovery. DME showed a performance close to butane. Since the cost of DME is lower than butane, it can be expected that production cost with DME injection is lower than butane. Considering that vapour pressure and density of DME are close to LPG products, its handling and transportation is as easy as LPG. Moreover, availability of DME is another advantage compared to butane. DME can be produced from natural gas or from renewable sources such as waste, wood, and agricultural products using well-established processes. A mobile production unit can be used to convert the produced solution gas to DME, which can reduce the methane emission and the costs of solvent injection.