Asset appraisal using pressure transient data relies on match between actual reservoir pressure response and analytical models. However, it has been found that existing analytical models are not adequate for complex reservoirs detected by modern pressure gauges. Therefore there exist high uncertainties in asset appraisal based on welltest analysis in these reservoirs. It is highly desirable to develop realistic mathematical models describing the behaviour of complex reservoirs for asset appraisal.
This paper demonstrates applications of a new mathematical mode to evaluations of two complex oil reservoirs. The flow regime in the first reservoir during test was identified by the new model as linearly supported radial flow (LSRF). The new model provided a significant improvement in matching pressure transient data and data interpretations. The interpretation results were verified using a numerical welltest simulator.