简介：2008年10月12日至15日，越南举办了SPE应用技术研讨会，讨论了欠平衡钻井和管理压力钻井技术。共有来自16个国家45个不同机构的80人参加了讨论，主要讨论了欠平衡钻井与管理压力钻井技术在提高钻井效率，增产和降低风险方面的价值。

The Vietnamese city of Ho Chi Minh was the host of an SPE Applied Technology Workshop (ATW) titled “Underbalanced and Managed Pressure Drilling: Technologies for Improving Drilling Performance, Enhancing Production and Reducing Project Risk.” From 12 to 15 October 2008, 80 participants representing 45 different organizations from 16 countries discussed the value that underbalanced and managed pressure drilling (UBD and MPD) technologies can deliver to a range of projects worldwide.

UBD and MPD technologies are employed to accurately control annular pressure during the drilling and completion of wells. The intention of MPD is to avoid continuous influx of formation fluids to the surface; any influx incidental to the operation is bled off and overbalanced conditions are quickly restored. In the case of UBD operations, the pressure exerted in the wellbore is intentionally less than the pore pressure of the exposed formations with the intent of bringing formation fluids to the surface.

When used correctly, both technologies can dramatically reduce well construction time, reduce or eliminate drilling fluid formation impairment, reduce mud loss costs, and lower nonproductive time created by kick control. In addition, they can deliver a range of downhole information that can be used to optimize well designs and field development plans to improve overall field efficiencies.

This ATW was designed to further the understanding among operators and service providers of the potential of these technologies, and also to provide an understanding of optimal equipment designs for each application. The workshop also aimed to ensure that regional issues associated with technology uptake were better understood such that engineering and management staff could better capture UBD and MPD value for their companies, wherever they might operate.

Opening presentations set stage for UBD/MPD potential
The keynote address by Do Van Khanh, Chief Executive Officer of PetroVietnam Drilling Corporation, was titled “Petroleum Developments in Vietnam and the Application of Enhanced Drilling Technology to Improve Recovery.” He gave an upbeat assessment on Vietnam’s overall petroleum activity and the impact that MPD was beginning to have in the granite basement reservoirs. MPD has also been successfully employed as a drilling enabler, to solve kick/loss problems in carbonate reefs above the clastic reservoirs.

Khanh also mentioned his company’s recent successful MPD operation on their rig PVD-1 which achieved a record measured depth for Vietnam. He also discussed the overall petroleum picture in Vietnam and recent new developments among PetroVietnam and the other companies operating in the country.

Ben Gedge, one of the cochairs of the ATW and Vietnam Country Manager for Weatherford Vietnam, gave the opening presentation entitled “Where Have We Come From–The Shift to MPD.” He took the attendees through the last 10–15 years of UBD and, more recently, the shift to MPD—particularly in the Asia Pacific region—where MPD technology is proving to be a valuable drilling enabler.

ATW Cochair Dave Elliott, the Global Tight Gas Well Technology Focal Point for Shell E&P International, followed with a presentation entitled “Workshop Objectives and Our Focus for the Future.” His talk concentrated on which UBD/MPD technologies will be important over the next five years. Elliott projected that MPD as a drilling enabler will increase in use, especially in high-pressure/high-temperature and depleted wells. UBD is expected to increase in use with more tight gas projects, where it has value in drilling enabling, damage reduction, and reservoir characterization. Increased application of UBD in tight gas exploration and appraisal wells is also expected.

Tech sessions focus on real-world applications, successes
The first two technical sessions reviewed how MPD and UBD projects should be addressed to achieve a successful business case through to the planning and implementation phase. Several business cases were presented from around the world, including StatoilHydro’s business case for the Gullfaks and Kvitebjorn fields, several UBD and MPD projects and prospects in Vietnam, implementation of UBD and MPD in Shell Libya, and the staged implementation of automated MPD in depleted deepwater Gulf of Mexico reservoirs.

The second day featured two technical sessions, both titled “How to Get UBD/MPD Project Approval and Project Team Buy-in.” Presenters discussed ways in which UBD and MPD projects could be elevated to a higher level within a company and how to manage project risks once approval has been given. There was also specific focus given to implementing MPD to improve fracture orientation in fractured granite basement reservoirs, a topic that is particularly important to operators in Vietnam. The country has unique reservoir conditions in the fractured granite basement.

The third day’s sessions asked the questions “How Do We Get Out of the Hole?” and “How Do We Get Back in for Completion Techniques?” Various techniques for pulling the UBD/MPD tools out of the hole without damaging the wellbore were discussed, including the use of downhole valves, snubbing and stripping, employing hydraulic workover units, and incorporating chemical isolation. Several technologies were then highlighted for getting back into the wellbore to complete the well, including the use of swellable packers, drill-in liners, performing a completion under pressure with a downhole deployment valve, and drilling with casing in a UBD mode. Several of these technologies were also highlighted in a poster session held later that day.

A range of technologies in the MPD/UBD tool box were discussed in the next session, with particular attention on new projects and technologies which have been developed since the last Asia Pacific MPD/UBD ATW a year ago in Kunming, China. Some of the new technologies reviewed included Grant Prideco’s Intellipipe wired-drillpipe technology for high-speed, high-volume data transmission from downhole to the surface; the integration of a surface blowout preventer into MPD/UBD operations; rate of penetration gains from the use of clear drilling fluids; and improved methods of drilling-data acquisition during MPD/UBD.

Elliott closed the workshop with a summarizing address and a survey of when the next MPD/UBD ATW should be held. The consensus was to delay the workshop, which is traditionally held annually, and instead hold the next MPD/UBD ATW in 18 months time, again in Southeast Asia.