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Non- Conventional Enhanced Oil Recovery Methods are important for PDVSA in Venezuela in order to increase oil production. Active improved oil recovery projects in PDVSA oilfields are mainly done by water injection in reservoir flanks, water injection by pattern, and by gas injection in the crest. Most of the production associated to these projects represents more than 40% of the total oil production, which includes condensate, light and medium oil production. In most of the cases, the recovery factor of the water injection projects do not exceeds 30% of original oil in place; whereas in projects under gas injection they can reach a recovery of 45%. Over the last 7 years, more than 50 wells have been treated with gels formulated at PDVSA-Intevep. The application is considered a successful alternative to improve injection profiles and/or productivity. In this work the effectiveness of Multigel® for gas shut off is tested. We included the diagnosis, design, and treatment in a producing oil well with a high gas to oil ratio located in North East Venezuela. The design of the treatment with both Multigel® and cement was done to isolate producing gas zones. The selective treatment and the results of the application of the technology are described. In the case of gel treatments a criterion adapted for the calculation of the volume must be used, in order to ensure the success of the application. The selection of a stable polymeric gel system at reservoir conditions is very important to guarantee a secure application and the operational sequence of the treatment. The main conclusion of this work is that there are three essential steps in a successful gel application treatment: diagnosis, design of the treatment and injection of the system in the field. In this application the combined gel-cement technique was used for gas blockade; it showed more effectiveness and assurance the complete seal to gas flow. The well was re-open to production with a low and permissible gas-oil relation, and now it is almost a half of the previous ratio before the treatment. |
