Comparison of conventional and catalytic in-situ combustion processes for oil recovery
in-situ combustion is the processes of injecting air or oxygen enriches air into oil reservoir through injection wells. initially, communication within the reservoir is created and then the crude oil is ignited, so that a combustion front is propagated towards the produced well. It is able to improve the quality of crude oil via thermal cracking in the reservoir. to achieve the required refining and marketing specifications, further upgrading beyond that achievable by thermal cracking is performed by catalytic processing in the reservoir.in this study, four series of laboratory in-situ combustion experiments were performed ton test the concept of its use to catalytic ally upgrade a medium- heavy Clair oil (19.8 deg API), using a low pressure combustion cell. samples of the crude oil/sand mixture were packed into the tubular cell and subjected to a heating program fro room temperature to 400 deg C, in a flow of air with an operating pressure of 3 bars. Two modes of experiments were conducted using horizontal tube position; first by packing the sample bed at the middle part of combustion cell and packing the catalyst bed at the outlet end of the sample bed, and secondly, by using a small-perforated tube inserted in outlet fitting of combustion tube, which serves as a horizontal well with the catalyst packed around the perforated tube. Tests were performed for both non-catalytic and catalytic procedures and for both dry and wet forward combustion runs. the results, which are analysed and discussed and based on the stabilised period of combustion (HTO region), show that the presence and loading the catalyst promote the combustion reactions and upgraded oil is produced.The hydrogen/carbon (H/C) ratio for all tests decreased as the combustion temperature increase, and was lower than that of the original crude oil. the (CO/(CO+CO2) ratios averaged from 0.2 to 0.26 in the non-catalytic tests, compared with 0.15-0.19 for the catalyst tests. These values demonstrated the success of the combustion processes. The air requirement and fuel consumption were observed to be slightly higher in the catalytic run experiments compared with the non-catalytic experiments, while they decreased slightly in wet combustion runs compared with dry runs. Also, from the catalytic experiments, it was found that the catalyst activity decreased with time, as could be observed in the slight reduction of the produced oil's API gravity for both the last two runs.Generally, the produced oil from the catalytic runs was upgraded up to 11 points compared with up to 5 points for non-catalytic runs; these compare very favourably with the original crude oi (19.8 deg API). High oil recoveries were achieved for all runs and ranged from about 53 to 74% OOIP. The highest oil recovery was achieved during wet non-catalytic tests, while the lowest was achieved during the dry catalytic tests.
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