Exergy Transfer Analysis of Thermal Driving Oil Process

Abstract

The signification of the exergy transfer phenomenological equation for multi-potential fields is introduced, and the concept of field influence factor of exergy transfer resistance is defined. Based on the analysis of the field structure for the thermal driving process, the exergy transfer analysis target is advanced, including the driving work(exergy), driving power(exergy flux), driving resistance(exergy resistance) and the field influence factor of exergy transfer resistance. In the end the aforementioned is illustrated with the hot water driving process. The numerical simulation result can reasonably illuminate the mechanism of some technical measures, such as high temperature decreases viscosity, high pressure gradient increases driving force, high pressure and low water rate decreases driving resistance. Keywords-thermal driving; exergy; exergy analysis; exergy transfer analysis; multi-field cooperation Thermal recovery method such as steam driving, hot water flooding, in situ combustion, is the main means of enhancing heavy oil recovery efficiency. From the point of improving oil displacement effect, the essential description of thermal driving process and its mechanism has special value and practical significance. Oil displacement mechanism which has obtained universal identity at present could be named as 'multiple oil displacement mechanism', it is the comprehensive function of multiple mechanisms including the viscosity reduction of heated crude oil, elastic energy caused by thermal expansion, heat medium displacement, soluble gas driving, miscible drive, gravity drive etc. Its characteristic is that each 'unit' mechanism acts respectively and crossly. Cooperation mechanism among 'multiple' mechanisms is very complex, which results in some key problems related to thermal driving effect getting difficult to solve, such as how to determine the structure composition of 'multiple' mechanism, how to discriminate the thermal driving weight of each 'unit' mechanism and so on, thus it is necesary to explore a mechanism description method which is clear, simple and can felicitously reflect the thermal driving essence. Exergy transfer is the subject to study exergy transferring and transforming rule. It is a crossly frontier subject of thermodynamics and transmission science which was born in the middle of 80's and gradually developed in 90's. To the kind of complex material transmission process such as thermal driving effected simultaneously by various energy forms, it is possible for this theory to transform multi-target into single