The use of chemical tracers to water injection processes applied on Romanian reservoirs

Abstract

The hydrocarbon reservoirs are extremely complex, each reservoir having its own identity. Reservoirs heterogeneity (mainly regarding the layered ones) frequently results in low recovery efficiencies, both under the primary regime and when different agents are injected from the surface. EOR processes efficiency depends on how detailed the reservoir is known and on the information related to fluids flow through reservoir. There are certain analyzes, investigations and tests providing good knowledge about the reservoir. The tracer tests are among them, being frequently used to water injection processes. Depending on the method used, IWTT (Interwell tracer test), SWTT (Single-Well Tracer Test), TWTT (Two-Well Tracer Test), information are obtained as related to: the setting of the preferential flow path of the injected fluid, the identification of water channels, evidencing the geological barriers, determining the residual oil saturation, around the well bore or along the tracer's path between two wells. This paper is focused on ICPT Câmpina efforts related to the use of the chemical tracers to the water injection processes applied to the oil reservoirs of Romania. It describes the usual tracers and the methods used to detect them in the reaction wells. Up to now, more than 50 tests with IWTT tracers have been performed on-site and this work presents some of their results. © Owned by the authors, published by EDP Sciences, 2013.