For some years SITEP and Eni have started to evaluate certain tertiary methods of enhaced oil recovery for El Borma, a mature tunisian field. A pilot project based on the application of a commercial chemical product called "BRIGHT WATER®" (BW), a trademark of Tiorco-Nalco, was chosen to verify on a real case its applicability and efficiency. The technology aims at the improvement of the oil recovery and at the reduction of the water production. This methodology is applied for oil mature fields, that are subjected to the water injection and that are presenting a heterogeneous reservoir with contrast of permeability. This paper describes the work performed to design a field test of such a technique in El Borma, with the twofold purpose to achieve the highest probability of success and gather as much information as possible to use in future applications. The project went through four phases: 1. Selection of one injector well and one producer; 2. Program of monitoring to verify the connection between the injector and the producer (injection of a tracer to determine the arrival time and simulation on a numerical model); 3. Injection of the polymerics and monitoring; 4. Application on the other zones of the field, in case of the success of the method. The first three phases were completed at the beginning of 2010. This work also describes the workflow which will be established to follow the improvements of the oil production.

El Borma is a mature oil field located onshore in the Northern Sahara Desert, Tunisia. Oil production commenced in 1966 and is currently supported by water injection; the high water cut (96%) and permeability contrast in the main reservoir (Level "A") indicated thief zones with less than optimum sweep efficiency prompting the evaluation of a tertiary method for improved oil recovery. In January of 2010 a pilot project (injector-producer) was implemented to evaluate a thermally activated particle (TAP) system as a strategy to improve the sweep efficiency of ongoing water injection program. This paper will summarize TAP pilot implementation and will describe methodology and results of project monitoring and injection-production performance. The evident good results of this TAP application (decrease in water cut with consequent increase in oil recovery up to 55%) in the last fourteen months justified a larger scale application in the field. The field scale application design was performed in two different steps: 1) Comprehensive production-injection data analysis of injectors based on the number of connected (offset) producers and channel volume estimations and; 2) The numerical simulation studies of most promising patterns calibrated with information generated during the first TAP pilot. Screening of patterns candidates and simulation approach of TAP will be also presented. El Borma pilot results validate the potential of TAP as an in-depth conformance strategy that can improve sweep efficiency of mature waterfloods. El Borma workflow to screen and rank patterns candidates combined with pilot project implementation, monitoring and evaluation can be used as a reference to evaluate the benefits of TAP technology in waterflooded oil reservoirs.