Wireless Telemetry Optimizes Test Duration in Rigless Well Testing

Abstract Rigless well testing with monobore completion has become a popular method for multi-zone reservoir testing on land. This paper introduces a new wireless telemetry system which integrates the acoustic signal technology with the wireline and slickline technologies in order to optimize the build-up duration and maximize the reservoir evaluation and improve the well test process. Rigless testing can utilize slickline, wireline and coiled tubing interventions to perforate, kick-off flow and set gauges with downhole shut-in tool (DHSIT). Traditionally, the downhole gauge data will be acquired in memory mode and retrieved for analysis after the build-up is completed. However, the data interpretation may not allow possible extension of the build-up period. The new solution offers the utilization of acoustic telemetry to read-out the data live from an assembly consisting of DHSIT, gauges and acoustic repeater (deployed via slickline prior to the flowback). This downhole set-up will be able to communicate wirelessly with another repeater deployed via wireline during the build-up period. Then, the data is transmitted through wireline to surface for real-time analysis and interpretation. The solution building and validation process included the system integrity test in the warehouse and later deployed in two runs. The first run allowed a design upgrade to improve the signal between repeaters above and below the DHSIT. Based on this, it is recommended adding the centralizers to have better metal-to-metal contact to increase the acoustic signal-to-noise ratio. The second run was successful where the wireless repeater was deployed via wireline after 10 hours from the shut-in time of the DHSIT's valve. It was positioned at 100 ft above the downhole valve and it started downloading all historical data from the gauge memory and kept recording in real-time during 36 hours of build-up. During this time there was no interruption in the data transmission and the data was delivered to petroleum engineers in town for real-time interpretation and decision making. During the pull-out-of-hole, the distance at which the signal would be lost was evaluated. The tool was stopped every 200 ft to check the signal quality and found that the longest distance at which the signal was received at 1,200 ft distance from the valve. The advantage of integration of the wireless telemetry with conventional slickline and wireline operation optimizes the test duration and provides complete reservoir information. It is also recommended to add a valve control option through wireless telemetry to be able to interrupt an on-going build-up episode without additional slickline run. Other recommendations are to improve the retrieval process by knowing the pressure differential and also to reduced number of fishing operations. For the first time, the wireless telemetry was introduced for rigless well testing. It was achieved by adapting the conventional acoustic telemetry used in the DST rig operations and integrating it with slickline and wireline technologies. This is also a step forward in developing real-time controllable DHSIT.