Determination of Residual Oil Saturation and Connectivity between Injector and Producer using Interwell Tracer Tests

Abstract

In this paper, based on simulation, a reservoir is first waterflooded and then the interwell tracer tests are used to determine the residual oil saturation (Sor) and connectivity in the region between the injector and producer pairs. In the end, the field wide average oil saturation from the simulation is compared with those from the interwell tracer test analysis. The simulation results shows that average Sor in the region between injector and producer pairs from tracer test analysis are much lower than the field wide average oil saturation obtained from simulation. This is probably because tracer tests only provide Sor in the region between different injector and producer pairs, without considering the oil in the upswept pore volumes, which may have higher oil saturations because their oil are bypassed by waterflood. Another reason is that significant percentage of oil is produced during the interwell tracer test. Final conservative
tracer recovery percentage in the end of the interwell tracer test for four producers show that producer P1 and P4 have a much higher connectivity to injector than producer P2 and P3.

Keywords: waterflood, interwell tracer tests, simulation, residual oil saturation