Abstract
Several deliverability test techniques are being used in the oil industry to generate a reservoir inflow performance relationship (IPR). The IPR curve describes the relationship between surface production rate and the flowing pressure at the bottom of the well (BHFP). The Absolute Open-Flow potential (AOF) represents a hypothetical gas flow rate that may be produced if the BHFP value were equivalent to the atmospheric pressure, i.e. the maximum flow rate that the reservoir may produce.
The most commonly known techniques for deliverability testing are:
Flow-after-flow
Isochronal
Modified Isochronal
Single-point
Although, these techniques are aimed to evaluate the production capacity of wells, most of them (the Isochronal, Modified Isochronal and Single-point tests) were developed to reduce the flared/vented gas and to minimize well testing cost. The flow-after-flow method requires stabilized flow for each of the flow periods, while the rest of the techniques only require stabilized flow at the last flow period test.
In this study, a radial simulation model was used to simulate the flow behaviour observed during application of the different well deliverability techniques mentioned above and to analyze and compare their flow stabilization times. These simulation results indicate that the stabilized flow condition is the main factor which influences the AOF results for any of the deliverability testing techniques used. Furthermore, the results emphasize that the use of a non-stabilized flow test may lead to an over estimation of well deliverability, especially for low permeability reservoirs.
