Drill stem tests provide crucial information on well deliverability and reservoir characteristics but gathering such crucial data may require many days of rig time, which can be expensive in deep water environment. As the information gathered during the test is generally available only when the string is pulled out of hole, well test engineers are usually conservative when designing the duration of the flow and shut-in periods to ensure sufficient data is acquired to meet the test objectives. However, in some cases, the planned test durations have not been sufficient to capture the necessary reservoir data for interpretation.

A very common practice to obtain bottomhole data before the end of the test has been to run a wireline cable to connect to the bottomhole gauges, but this may pose a major risk to the operations. Wireless downhole reservoir testing systems, which have recently been developed, can be the solution to this challenge. The system transmits information from and to the bottomhole tools in real-time without risk to operations.

This paper describes field cases where such a system was used in deep water wells offshore Brazil. The wireless telemetry system took less time to rig up than the wireline equipment and allowed the test sequence to be adjusted during the test. The data was available during flowing and shut-in conditions. It was used to monitor the clean-up efficiency in real-time and obtain key reservoir information before the end of the test. The paper reviews the benefits and limitations of the current technology and makes recommendations on how to use the technology most effectively.