Case Study: Well Testing Decisions Enhanced by Real-Time Data Delivery and 24/7 Engineering Support
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Online collaboration helps AGR Petroleum Services save rig time and improve well testing program on a North Sea appraisal well
Challenge: Anticipated pressures and production flow rates led AGR Petroleum Services to be concerned about cleanup efficiency and duration on a North Sea appraisal well.
Solution: A collaborative working environment was created with AGR Petroleum Services and Schlumberger experts to test well performance in real time.
Result: Direct communication between key personnel helped AGR Petroleum Services save rig time, reduce risks, and achieve test objectives efficiently.
Multiple stakeholders need real-time data for fast decisions
Offset well data, the choice of tubing string needed to keep the wellhead pressure above the bubblepoint, and the expected range of pressures and flow rates led AGR Petroleum Services to be concerned with the efficiency and the amount of time that might be required for cleanup on an appraisal well being drilled and managed for a Canadian-based operator northeast of the Shetland Islands in the UK sector of the North Sea. A two-zone, discrete well-test package, including drillstem testing with memory gauges, tubing-conveyed perforating, and associated subsea and surface equipment, was proposed by Schlumberger. An AGR Petroleum Services well test engineer requested that data be provided as soon as possible during the well tests to allow well performance evaluation during cleanup and to support fast operation decisions. Well test data had to be available simultaneously to experts in Aberdeen, London, and Canada.
24/7 quality control and onshore support
Following well completion and prior to the start of perforating operations, a data acquisition expert in the Aberdeen OSC operation support center remotely logged on to the offshore computer to initiate a quality control check of the acquisition software settings, sensor coefficients, and data transmission set up for the DART well testing acquisition, reporting, and remote data display system. The InterACT real-time monitoring and data delivery system was also tailored to meet AGR requirements, and OSC operations specialists monitored job progress 24/7 to ensure reliable, high-quality data transmission.
Although the well was perforated after the key personnel onshore had left their offices for the day, the InterACT system allowed them to monitor the perforating event and initial recovery in real time on their home computers.
In consideration of well off-loading progress and North Sea regulations, the onshore team decided to shut in the well until daylight after the reservoir fluid level rose above the downhole tester valve. When the well was reopened, experts on both sides of the Atlantic were able to monitor well off-loading and initial buildup in real time.
Real-time data interpretation and improved decision making
As flow was passing through the separator during the main flow period, a group of AGR experts attended a meeting in the Aberdeen OSC facility, where well performance was discussed with a Schlumberger reservoir engineer. Using real-time data, the engineer performed NODAL production system analysis and calculated the tubing-string flow velocity to predict cleanup efficiency. The engineer also calculated the flowing bottomhole pressure at different choke sizes. Once several step rates with the well flowing through the test separator had been performed, the inflow performance relationship (IPR) curve was plotted. Based on the IPR data, AGR Petroleum Services personnel decided to alter the test program.
A real-time collaborative environment created using the InterACT system with OSC support allowed direct communication between key personnel onshore and offshore, resulting in operations being performed safely and efficiently.
During the buildup period, AGR and operator experts grew concerned that the reservoir objectives might not be met and considered extending the testing. The Schlumberger reservoir engineer performed forward modeling of the buildup based on the expected reservoir parameters and the flowing-period interpretation. The modeling results enabled testing to be concluded as planned, meeting all well objectives, and saving 6 hours of rig time.
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