COMPOSITION AND METHOD FOR PREPARING WATER-IN-OIL EMULSIONS USED IN CRUDE-OIL EXTRACTION

摘要

The present invention pertains to the extraction of petroleum products and more precisely relates to compositions and methods for preparing water-in-oil emulsions. These emulsions can be used for adjusting the injectivity profile of injection wells and/or for isolating the water inflow in oil wells. In order to increase the kinetic and aggregative stability of the water-in-oil emulsions thus produced, this method comprises using as an emulsifier raw and heavy crude oil which contains gumming-asphalt, which has a high porphyrin-complex content of at least 100 νg/g and which has not been submitted to any thermal-chemical treatment. The oily phase comprises a mixture of paraffin-based liquid hydrocarbons as well as a heavy solvent, wherein these components are selected in amounts by volume such that the (oily phase) mixture density is equal to that of the water used for preparing the water-in-oil emulsion.