Using interwell tracer test to determine the remaining oil saturation

Interwell tracer test hasn't been widely used for many years because only average parameters from injector to producer can be determined from interwell tracer test data. In order to get more useful information, a three-dimension two-phase (oil, water) four-component (oil, water, partitioning tracer and non-partitioning tracer) mathematical model has been established and the tracer numerical interpretation model has been developed. Based on this model, the pressure, saturation and tracer concentration can be obtained, then the distribution of remaining oil saturation can be obtained by matching the tracer production curve numerically, and this is very important for the later development of the oil field. This paper presents the basic theory of how to get the information of remaining oil saturation from the data of interwell tracer test. Tracer test data of 76-30 well group of the Guan-104 fault block in Dagang oil field have been analyzed by this model. The distribution of oil saturation from this model is consistent with the result of reservoir performance and geological analysis. So it is concluded that this model is accurate and reliable. With the development of the interpretation method, interwell tracer technique will play more and more important role in waterflooding oil fields.