Environmental and safety considerations for ultrahigh-rate offshore well testing

Well testing and cleanup obtain critical data for determining a well’s productivity, but conducting them on space-constrained offshore platforms poses additional HSE challenges.

An operator is facing this situation in developing a major deepwater gas condensate field. The expected ultrahigh rate for the multiwell campaign necessitated employing a dual testing train with more than twice the usual number of monitoring stations, including at pressure control valves more than 150 m from the well test area. Of particular concern is monitoring burner operation to maintain proper performance, including fallout, smoke, and deluge. The conventional approach is to physically station a crew member to observe the burner, in conjunction with numerous other manually performed tasks to read gauges and collect and analyze samples.

In addition, communication of the large volume of resulting information from the dual test equipment to the crew and the operator was inefficiently distributed across a variety of channels, potentially leading to delays and slowing understanding as to whether test objectives were being met.

Automated test monitoring and real-time communication

To improve well test data collection, analysis, and communication for better informed, collaborative decision making, Schlumberger integrated Concert live performance with the well testing operations. This compact well testing platform combines a flexible wireless sensor network and video cameras for inline, continuous digital data acquisition and analysis. The well crew is equipped with ruggedized tablets and wearable communication technology, with a web-based dashboard providing the same data and video display and analysis with voice communication capability for the crew and the operator offices alike.

A quantified holistic view for more effective well testing

By replacing manual measurements with continuous real-time data and analysis, Concert performance significantly increased well testing efficiency for flow at ultrahigh rates. The elimination of manual sampling and burner observation by personnel also enhanced both the crew safety and environmental compliance. The driller was able to easily monitor the casing pressure in real time during flow instead of waiting for individual reports.

Using the HD video cameras for streaming surveillance of combustion at the two burners enabled real-time response for maintaining environmental compliance. Without exposing the crew to the extreme heat radiation as conventional monitoring would, Concert performance guided ensuring that the pilots remained lit, air compressors ran at optimal level, the deluge water curtain worked properly for heat suppression, no nozzles plugged, flame color was correct, and the separator performed well. Additional WiFi-connected sensors continuously monitored the line bore pressure to avoid developing erosional velocity from the ultrahigh flow.

Because Concert performance provides a quantified holistic view of the well test spread, the Schlumberger engineers and the operator were able to concurrently interpret test performance as testing was conducted. Having real-time analysis of pressure and temperature trends enabled developing previously unavailable insight in evaluating the test results. This saved rig time by preventing the repetition of tests because of unrecognized fluctuation in the atmospheric temperature.