Emmanuel Franco Nogueira, senior petroleum engineer for Petrobras, presented his company’s experience with MPD and what the technology means for Petrobras during a presentation at the 2011 IADC/SPE Managed Pressure Drilling & Underbalanced Operations Conference & Exhibition last week in Denver, Colo. “The Petrobras philosophy for MPD first is kick detection. Maybe we can change this in the future, but so far, it’s kick detection, and also to help us on complex wells,” Mr Nogueira said.
Since discussions began with Secure Drilling in 2004, Petrobras has embarked on several field trials of MPD systems, Mr Nogueira said, starting with simple wells and moving progressively into more complexity. “The goal of the first two tests was to evaluate the performance of MPD in a high-temperature environment … because the main question is, are those electronics going to survive the high temperatures?”
The first field trial was conducted on an onshore exploratory well using a small kelly-operated rig and a water-based mud system. The well provided information on the impact of pipe movement on flow and flow measurements and confirmed the benefits of using a top drive versus a kelly due to the wear life of the element in the rotating control device, Mr Nogueira said.
With the second field trial, Petrobras switched to a rig with a top drive to drill the 8 ½-in. and 12 ¼-in. sections of a development well. It took 44 days to drill 2,372 meters.
On the third field trial, problems were encountered in the deep well, and it took approximately 130 days to drill the 8 ½-in. and 12 ¼-in. sections (3,900 meters). The system was able to detect a gas influx, which was controlled on surface.
The fourth field trial involved a jackup, drilling an exploratory well in a field where five exploratory wells had been drilled previously. However, in those five wells, “they couldn’t get any good information because they were so overbalanced,” Mr Nogueira said.
With good ECD management, it took approximately 50 days to drill 1,507 meters in the 8 ½-in. section, which was extended 500 meters from the original plan. Whereas previous operations used 12-ppg mudweight, this well used 9.7-ppg mud (later increased to 10.3 ppg after a confirmed kick). Nonproductive time on previous wells were also very high, and it was reduced on this well, he said.
Currently, Petrobras is looking at using MPD in the Santos Basin. “We have some very tough wells here,” Mr Nogueira said, referring to the basin’s pre-salt area. An exploratory well deploying MPD is expected to be spud by the end of June 2011 using Diamond Offshore’s Ocean Baroness semi. It will be located in shallow-water depths in Santa Catarina State’s Ilha do Macuco. The HPHT well is planned for 6,300 meters total depth.
“MPD is a good tool and will help not only Petrobras but all the companies,” Mr Nogueira summarized, adding that Petrobras is also looking to take MPD into deepwater in the future.