METHOD FOR DETERMINING A TRANSIT TIME FOR A RADIOACTIVE TRACER

摘要

An improved method for determining the transit time of a radioactive tracer for steam injection profiles in steam injection wells is disclosed. Radiation decay data is collected at two detectors at different depths. The data is then transformed into a new data set, consisting of time intervals between successive decay events. Tracer radiation decay events are distinguished from background radiation decay events by using statistical methods to establish a high probability that background radiation decay events are excluded. The total set of time intervals are then divided into subgroups of a specified sample size. The arrival time of the tracer is determined as the first time at which a specified minimum number of identified tracer radiation decay events occur successively.