Novel single well chemical tracer test design: shut-in time determination for test feasibility

The well shut-in time (tsoak) in a single-well chemical tracer test (SWCTT) after injection of the primary tracer depends on its reactivity under reservoir conditions. In this paper, a novel SWCTT design is proposed to determine the well shut-in time to minimize the risk of loss of test results based on different secondary tracer generation rates considering the oil saturation of the reservoir. The developed method in this paper was approximated to conduct SWCTT in oilfield A in predicting the minimum tsoak after ethyl acetate injection for different Sor. The paper shows that the field test tracer production curves are consistent with hydrodynamic modeling data at the same tsoak. When tsoak is reduced according to the model data, the concentration profile of the secondary tracer is in the low detection range, indicating that the test was properly organized when the well shut-in to minimum tsoak. Thus, the novel test design showed how the time of all well operations can be optimized and the costs associated with equipment mobilization and service company operations can be reduced.