Concurrently in the West of Venezuela, they have come proposing technicians to improve the recovery of oil weighed through of new processes of thermal stimulation that do not use water steam as agent of heating.
In this work it is considered the injection of hot gasoil the reservoir and exists the thermal stimulation process´s physical mathematical foundation, based on the several mechanisms of heat transference as convection and conduction, as a whole with the mechanism of transference of matter for liquid diffusion - liquid, which one, it based in: A Balance of calorific energy, through it is determinated distribution of temperature in the reservoir, and the heat losses to the adjacent formations evaluated by the model of Marx and Langengein, besides the model of production defined by Boberg and Lantz. A Balance of matter ruled by Fick's Law of the diffusion oil -solvent , and the equation of difusitivity that governs the transitory behavior of pressure defined by Everdingen and Hurst.
The stability of the simultaneous solution of the differential equations system is acceptable, due the founded solutions are analytical type.
Operationally the efficiency of the stimulation and the field practice, they will be key points that there will allow the successful execution of the planned process, through the wells completation with sand control filters, sensors of pressure and temperature, besides the thermal equipments of completation that requiere the thermal processes.
To illustrate the field application of the proposed technology, there was selected the reservoir Bachaquero-01.
The results obtained in several running of sensibilities, indicate that it is achieved an increase obtains in the mobility factor of the oil at reservoir conditions of 10,5 times superior than the original one. Giving cycles of production of approximately 10 months, for a stimulated average rate with hot solvent of 850 BN/day versus stimulated average day with steam of 380 BN/day, in an arrangement of conformated wells by two horizontal ones in parallel.
The obtained results indicate that the heat solvent injecting technology to the formation is more favorable alternative than the steam alternate injection process, due it is predicted a major optimized recovery of oil by cycle.
The use of hydrocarbons solvent liquid, as the naphtha, kerosene, gasoil, they have been used to improve the process of the recovery of oil for steam injection, and to been reported and studied in a lot of works, even several processes have been patented depending on the type of solvent used, specifically in the injection of vapor/solvent. Allen (1976), proposed the use of a pot-hole of mixture composed by an aromatic hydrocarbon as solvent and a gaseous component as dioxide of carbon, to establish a preferential way between the well injector and the producer well , after which the oil is moved for constant injection of warm water or steam. Best (1979), Otherwise, he present a improved stimulation with steam in which one the oil in the formation is submitted to one o more steam cycles, followed of a pot-hole of mixture of a hydrocarbon solvent before the following cycle of steam injection.
Later, Buckley and Grist (1980) propose the injection of a pot-hole of mixture of a distilled solvent, as tolueno or refined oil mixed with an oil sulfonato surfactante, in order to increase the permeability to the water in the reservoir before the injection of the steam. In this case, the proposed solvents and the schemes might be used in the cycles of steam injection, as well as in any process of thermal stimulation with steam.
Islip y Shu (1984) present an invention that consists in the injection of a given quantity of a steam and solvent with the producer closed well. The injector well is then closed and the producer well is opened to extract the fluids from the formation, these stages are repeated cyclically in the time.