Since there are a lot of reservoirs of highly viscous heavy oil, whose extraction is a challenge for petroleum engineers in Venezuela, and also the significant gas shortage, which makes many of the gas injection projects in our reservoirs in the west of the country have been suspended are reasons why it has raised the need to explore alternative sources for the recovery of such highly viscous oil. Improved Recovery processes emerge as an alternative to increase hydrocarbon recovery, changing the characteristics of the fluids and the capillary forces acting on them. Enhanced recovery is mainly based on sophisticated techniques in operation, is usually costly, but very effective, therefore, the enhanced hydrocarbon recovery is defined as oil production, by injecting a fluid, in addition to displace oil, favorably modifies the oil recovery mechanisms. The techniques can be applied at any stage during the operation of the reservoir; in fact, there are formations which for its geological and petrophysical characteristics can only be exploited by Enhanced Recovery techniques. Several factors play a role in the selection of the most economically attractive alternative, these factors are: The rock type and characteristics that have the greatest influence on the pattern of exploitation is undoubtedly the porosity, permeability, reservoir fluid, and the last factor is the injection fluid to be introduced to the reservoir. The selection of the fluid to be injected either to maintain reservoir pressure, move, or modify the mobility of hydrocarbons, are carried out based on the analysis of the molecular interaction between the injected fluid and oil in a reserve.The present study shows the results of the Evaluation of Different Secondary Recovery Process in Reservoir BACH-01 to increase the recovery factor of the same; this reservoir is located on Lake Lagunillas Exploitation Unit. It was built a numerical simulation compositional model using the simulator STARS of CMG company, to represent the geometry and dynamics of the reservoir fluid flow, thereby validating the rock / fluid properties. Among the different methods studied is the CO 2 injection, the Alternating Steam Injection more Gas (IAV ϩ GAS), SAGP y VAPEX.

The Bach-01 reservoir has one of Heavy Oil Reserves (12° API) the most importan West Venezuela with an OOIP 6621 MMSTB. Stratigraphically the reservoir is comprised of Miocene sediments (Member Bachaquero, Lagunillas Fm) with a thickness of 750ft, the product of sedimentation prograding fluvial-deltaic domain, being divided into 8 intervals informal (AP, H, G, F, E, D, C, AB), which are marked differences in thickness, rock quality, facies and distribution of fluids. On the other hand, the development plan of the field horizontal wells has been based only on exploiting the upper sand (AP unit), which represents 75% of the OOIP. In this research, we have visualized and conceptualized new opportunities for development of heavy oil reserves, by optimizing steam injection in horizontal wells, through gas injection during the soaking period (CSS+GAS). The work integrates geological and reservoir of upper-lower sands and thermal evaluation of the optimal parameters of steam injection and rock-fluid characterization. In this research were used field data for making model pit that is the representation of the behavior of production wells, subjected the process of css+gas and weighted data reservoir, for performing a pseudo-compositional thermal simulation black oil system, through which were evaluated the effects caused in the reservoir, by css+gas process. The most outstanding results concerning this process were: increase oil accumulated by cycle, increased volume of the steam chamber in horizontal wells and, decreased viscosity.

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