SPE and IADC Members Abstract The implementation of a new type of well profile. the designer profile, has resulted in increased recovery and production rates. The geologically complex Gullfaks Field (See fig. 1), located in the Norwegian sector of the North Sea, has seen significant change in the initial field development plan (FOP) as a result of the design technology. A new type of well profile was necessary to increase both total recovery and production rates from Gullfaks platforms A, B and C. Advances in steerable technology and directional drilling performance enabled a three dimensional horizontal I extended reach well profile, now designated as a designer well, to be utilized to penetrate multiple targets. This paper presents the concept. motivation, performance, results and conclusions from four designer wells used in the revised FDP. Introduction The Gullfaks Field, block 34/10 (See fig. 2) in the Norwegian sector, is the first license ever run by a fully Norwegian joint venture corporation. The license group consists of Statoil (operator), Norsk Hydra and Saga Petroleum. The field currently produces more than 85,000 5m /day of oil from three main reservoirs of the Jurassic age. The field produces from three separate Condeep (OBS) platforms; Gullfaks A, B and C. Gullfaks A and C are fully independent processing platforms with three separation stages. The Gullfaks B platform provides processing facilities for single stage separation only and transfers oil to both Gullfaks A and C for further processing. The Gullfaks Field has a very complex reservoir with numerous fault blocks and structures. Reverse faulting, in areas dominated by normal faults, accentuates the complexity of this reservoir. To date, approximately 70% of all GulIfaks wells have encountered small-scale faults not previously detected by seismic imaging, which again adds to the challenge presented by this field. Approximately 100 wells will be necessary to properly develop the Gullfaks Field according to the FDP. Generally, two producing wells are accompanied by one injector well. With the initial FDP approved in 1981 and an updated FDP approved in 1985 it is easy to understand its revision in light of the combination of technological advances and increasing knowledge of the reservoir with each well drilled. MOTIVATION FOR NEW PROFILE The initial FDP was based upon well profiles with minimum displacements of 3 km and maximum inclinations of 60. As the early production levels were below expectations, concern existed regarding future production levels on Gullfaks wells. Optimized multiple targets and optimized borehole placement were felt to be critical to improving the production rates and total recovery on the Gullfaks Field. To optimize both the targets and borehole placement, in this geologically complex field, would require substantial turn in the horizontal plane. The drilling department expressed concern about the ability to drill highly deviated wells with large turn in the horizontal plane. As steerable technology improved and the level of execution of the directional companies providing steerable motors improved as well, both management and the geology department were increasingly confident that this type of well profile could indeed be drilled successfully. P. 255^

This paper descnbes strategies and techniques employed to extend the drilling reach in the Gullfaks field, offshore Norway. Field development plans were originally based upon deviated wells drilled to a maximum inclination of 60°and a maximum displacement of 3 kID. Emerging horizontal drilling techniques encouraged a reevaluation of these field development plans. These techniques are now being implemented to increase the inclination and extend the reach to 5 kID in support of the revised plan. The early success achieved has urged further consideration of extended-reach drilling to as much as 10 kID.

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fax 01-972-952-9435. AbstractThe benefits of continuous rotary drilling in directional wells through application of 3-Dimensional Rotary Steering Systems (3D RSS) are well documented in the industry. ExxonMobil Development Company (ExxonMobil) continues to expand application of these systems where economic incentive exists. ExxonMobil's targeted strategy to influence the development of low-cost 3D RSS has been published 1 and has generated further discussions with 3D RSS providers. This strategy is intended to accelerate the development of lowcost 3D RSS in order to capture benefits of this technology to improve drilling performance and economics, particularly in lower-margin projects.This paper describes the results to date of the application of our stated strategy. Systematic usage of the tools in various modes (maintaining verticality, building/dropping angle, holding angle and azimuth, etc.) have given the provider valuable real-world testing to validate and improve tool design and to improve reliability of components. The role of field testing in support of the development plan, results of applying this technology at its current level of development and an assessment of its value will be discussed.