Optimize Critical Well Testing Operations in Real Time | Schlumberger
Case Study
Location
United States, North America, Offshore
Details

Challenge: Conduct an extended well test in the deepest water (7,000 ft) and the highest pressure (25,000 psi) yet in the US Gulf of Mexico with real-time surface readout of bottomhole pressure and temperature

Solution: A semi-permanently deployed WellWatcher real-time reservoir and production monitoring system

Results: Reliable, uninterrupted real-time bottomhole data acquisition for 48.5 days from all three downhole gauges while monitoring sustained flow rate of 6,000 bbl/d of oil; minimized rig time spent to achieve well test objectives

Products Used

Optimize Critical Well Testing Operations in Real Time

Chevron uses Schlumberger technology in record Jack well test

Deep water, high pressure

Chevron planned an extended well test in the deepwater Jack No. 2 well in the Gulf of Mexico. Reliable, uninterrupted real-time data had to be obtained in 7,000 ft of water and a total depth of 27,500 ft, plus very high pressure of 25,000 psi. Reservoir uncertainties and extremely high daily rig spread rates required maximum efficiency.

The Jack well is in 7,000 ft of water.
The Jack well is in 7,000 ft of water
Depiction of typical dual gauge mandrel carrying two of three high-pressure quartz gauges in the test string.
Depiction of typical dual gauge mandrel carrying two of three high-pressure quartz gauges in the test string.

Robust gauge system

With the drillstem test string, Schlumberger ran a reliable WellWatcher permanent gauge system consisting of three quartz pressure and temperature gauges—rated for 25,000-psi and 425 degF—deployed using one dual and one single solid gauge mandrel and welded Intellitite electrical dry-mate connectors. The proven reliability of the welded connector technology used in this system was considered a key advantage over wireline-deployed gauge options to acquire this data.

The electrical signal was routed through the SenTREE high-pressure subsea well control system on the seafloor. At the surface, the pressure and temperature information was monitored by Chevron and Schlumberger personnel in real time during well test operations. This real-time surface readout was critical to the safety and efficiency of this well test.

Uninterrupted data stream

The Schlumberger gauge system transmitted critical downhole annulus and flow-stream bottomhole pressure and temperature information uninterrupted for 48.5 days. The well test averaged 6,000 bbl/d of oil.

The system facilitated onsite transient analysis of the downhole flowing and buildup data, allowed engineered execution of the well test, maximized well test flow rates while minimizing the risk of excessive drawdowns, minimized the rig time required to fulfill the objectives, and supplied invaluable assistance to drillstem test specialists.

 

The Schlumberger gauge system transmitted critical downhole annulus and flow-stream bottomhole pressure and temperature information uninterrupted for 48.5 days.

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The Jack extended well test was in 7,000 ft of water
Products Used

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