Four-well comparison in Papua New Guinea: high-risk, high-angle wells demonstrate extended wellbore stability and faster drilling time with inhibitive high-performance water-based fluid
Angus Florence A , Mike Dow A , George Shieh A and JV Babu AA Halliburton
B Oil Search Ltd
C Halliburton Australia Pty Ltd
The APPEA Journal 51(1) 119-126 https://doi.org/10.1071/AJ10007
Published: 2011
Abstract
A four-well project located onshore Papua New Guinea provided an opportunity to compare the performance of two inhibitive drilling fluids in the problematic 12¼” interval. Wells A and B were drilled using a conventional KCl/glycol fluid. Wells C and D used a high-performance water-based fluid (HPWBF) containing a shale inhibitor that also provides lubricity. All four wells were drilled with the same rig. The base brine for both fluids was KCl.
All hole sections were directionally drilled from vertical to near horizontal by section TD through a claystone interval. Tectonic wellbore breakout was present in all four wells, and the position of the breakout in the wellbore varied from well to well. Well A was regarded as the easiest well to drill due to the breakout being on the sides on the inclined well bore (horizontal), and Well D was regarded as being the most difficult well to drill due to the breakout being located directly on the top and bottom of the wellbore (vertical).
Performance comparisons were made using on bottom rates of penetration, tripping times, casing running times, and overall hole section costs. These data have been normalised to remove non hole related NPT events.
The KCl/glycol system provided sufficient wellbore stability in Wells A and B with horizontal breakouts and with non-optimal breakouts with very limited openhole exposure. For higher risk wells C and D with non-optimal breakout positions however, the HPWBF offered improved reliability and ensured there was no performance decline. Outstanding performance occurred in Well D where the HPWBF maintained good wellbore stability over a 56-day exposure.
Although the KCl/glycol fluid had a lower cost/bbl, improved overall cost savings were achieved by using the HPWBF in the high-risk wells.
This paper addresses all operations performed while drilling and casing the 12¼” interval. Possible causes for performance differences are evaluated, taking into account that mud systems represent only one variable. As other variables were introduced progressively, it was possible to back these out to determine mud system effectiveness.
Angus Florence graduated from the University of Aberdeen in Scotland in 1978 with a bachelor of science (Hons) in engineering. He joined Baroid as a drilling fluids engineer in 1982 and worked for seven years in the field–mainly in Saudi Arabia and the UK North Sea. He then held supervisory operations roles in Denmark and Norway before taking a technical advisor position for Baroid’s technical services team in Aberdeen, Scotland. In 2006, Angus moved to Jakarta as Indonesia technical manager, then on to his current role in January 2009 as technical manager for Halliburton Baroid for Australasia. angus.florence@halliburton.com |
Mike Dow graduated in 1985 with a bachelor of science (Hons) in geology from the University of Aberdeen, Scotland. He started his career in the oil field as a data engineer with Exlog. In 1992 Mike joined Baker Hughes Drilling Dynamics group and, in 1996, became a drilling optimisation engineer with Baker Hughes OASIS group. Mike joined Oil Search Ltd in Sydney as a senior drilling engineer in 2003 and transferred to their Yemen operations in 2009. Mike is currently Yemen drilling superintendent for Oil Search (ROY) Ltd. mike.dow@oilsearch.com |
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George Shieh is a drilling and completions engineer at Oil Search Limited in Sydney. He holds a bachelor's degree in petroleum engineering from the University of New South Wales. george.shieh@oilsearch.com |
JV Babu has been working in the oil industry for the previous 14 years. Babu has a bachelor's degree in agricultural sciences and a master's in management systems. In his 14 years in the industry, Babu has worked in the field as mud logger, data engineer and drilling fluids engineer in various locations in Australia and Papua New Guinea. For the previous two and a half years, Babu has worked as a coordinator for Halliburton Baroid based in the Oil Search office in Sydney. jv.babu@halliburton.com |
