Vaporized hydrocarbon solvents near and below their dew points can be usedfor the recovery of highly viscous heavy oil and bitumen. The process, "Vapex", being developed in this lab, may replace the thermal processes currently usedfor recovering these otherwise unrecoverable reserves. Hydrocarbon Solventscause reduction in viscosity due to dilution (and deasphalting when used insufficient quantity) and enhance the flow of oil. Advantages of the process, tomention a few, are:

  1. High energy efficiency and negligible heat loss,

  2. Low effluent handling and related environmental hazards and

  3. In situupgrading of oil.

In our earlier experiments, carried out in a Hele-Shaw cell, it was observedthat asphaltene deposition does not prevent the flow of oil through thereservoir, on the contrary there was an enhancement of production rate. Thiswas mainly due to the drastic reduction of viscosity caused bydeasphalting.

In the present work results of experiments carried out in a scaled packedcell using butane as a solvent is described. Pressure limitation of thephysical model available was the main reason for using butane instead ofpropane. The low pressure characteristics of the process could allow it to beutilized to extract bitumen from shallow but non-minable reserves. Themechanism of the Vapex process is basically the same for propane and butanethrough the production rate is different.

The experimental results show that the flow rates in a packed cell arehigher than those obtained by scaling up the results of Hele-Shaw cellexperiments carried out with butane using identical conditions of temperatureand pressure. The reason for this is studied and described. Flow ratespredicted from these results indicate that the process has potential for fieldoperations.

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