This paper discusses specialized completion tools and techniques developed while drilling and completing the open hole sections of 20 horizontal gravel packs and 3 Level 5 multi-lateral wells completed in Campos Basin, offshore Brazil. The discussion covers wellpath planning, pumping operations, wellpath selection, multilterals, the use of extended-longevity well screens, floating rig operations, and fluid systems to prevent formation damage. Open hole horizontal wells are attractive in ultra-deep water because the approach eliminates a liner and allows a larger casing string at the reservoir. This method also provides extensive reservoir exposure. Couple this technology with multi-laterals and a significant reduction in the number of wells to adequately drain the reservoir may be achieved. Twenty open hole completions have been successfully performed in the deepwater Marlim field offshore Brazil. These include both gravel- and non-gravel-packed completions in horizontal producers and injectors. Additionally, three Level 5 multi-lateral wells with open hole completions have been successfully installed in the same field. Multi-lateral (ML) completions have been classified as Levels 1 through 6, depending upon junction functionality. Only Levels 5 and 6 pertain to this discussion. Only Levels 5 and 6 provide pressure integrity at the junction. Level 5, a cased and cemented main bore and laterals, achieves pressure isolation at the junction with packers. Level 6 is similar to Level 5 except that pressure isolation at the junction is achieved using the casing. Introduction The economic viability of deepwater projects requires effectively draining the reservoir with a minimum number of wells. The completion types of choice are either long horizontal wells or multi-lateral completions.4 In unconsolidated formations, it becomes necessary to control sand production to effectively produce the reservoir. Open hole gravel packing has been gaining in popularity as the preferred sand control technique for horizontal wells. Significant advances have been recently achieved to substantially extend the length of laterals that can be successfully packed (with lengths exceeding 1000 meters being relatively common). Technology is also under development to reduce the negative effects associated with the presence of hydratable shales in the production interval. The fact that gravel packing helps to minimize well interventions and risk if planning and execution are properly carried out leads to this completion type being very desirable to deepwater applications. While stand-alone screens are often used for this purpose, it has become clear that gravel packing extends well life as required for economic viability of deepwater installations.5,6 Petrobras has been employing open hole gravel packing as well as stand-alone screen completions in their horizontal well and multi-lateral completions in the Campos Basin (Figure 1).1,2 To date, 20 horizontal open hole gravel packs and 3 Level 5 multi-laterals have been successfully installed from floating rigs. Both of these innovations were the first of their kind. With the success of isolated junction technology, both laterals of a Level 5 or Level 6 multi-lateral well can be effectively gravel packed. This can provide extended well life and improved reservoir management. Additionally, with the proper use of inflow control devices, relative flow from each branch of a multi-lateral can be controlled. The Campos Basin, home for 61 separate fields (seven of which are classified as giants)7 in water depths ranging from 100 to 2,000 meters, is one of the major deepwater developments in the world. In this challenging environment, Petrobras first performed horizontal gravel packs in water depths exceeding 700 meters, and the first Level 5 multi-lateral wells were constructed from a deepwater floating rig. For both of these applications, operating from a floating rig in a deepwater environment posed significant challenges that had to be overcome. In particular, successful horizontal gravel packing required that hole cleaning be effectively employed (even with the presence of a long, large-diameter riser).

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractWithin the last two years, multilateral systems offering full hydraulic and mechanical integrity have become commercially available in the petroleum industry. Emphasis has now begun to shift toward increasing the flexibility of these systems while minimizing the overall risk associated with the implementation of the multilateral. This paper details the development of a new Level 6 (TAML) type of multilateral that offers mechanical and hydraulic integrity and allows full liner bore access into either lateral, as demanded by the industry. Descriptions of the system and its development are discussed along with an assessment of the risk minimization possible with this new type of multilateral as compared to current state-of-the-art multilateral systems.

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractMultilateral technology has become a catalyst for enabling deepwater development.This challenging environment dictates that functionality and junction integrity are key requirements for multilateral completions. For an injection well in the Voador Field, offshore Brazil, a TAML Level 5 multilateral completion was implemented from a semisubmersible rig to achieve the junction isolation required for this application. It is the intent of this paper to demonstrate that a complex TAML Level 5 multilateral completion can be professionally designed, managed, and implemented from a semisubmersible rig, while saving ten million dollars (US) in costs over conventional technology applied in this region. This will be accomplished by reviewing the operator's deepwater development philosophy, reservoir considerations, design, operational procedures, and overall cost information related to the completion. In addition, details of the challenges faced, problems solved, and lessons learned will be examined on the world's first TAML Level 5 multilateral well completed from a semisubmersible rig, the Petrobras 8-VD #6HP-RJS and #7HPA-RJS dual lateral injection well in the Campos Basin off the coast of Brazil. Voador Field Reservoir DevelopmentGeneral Philosophy and Strategy. The operator, Petrobras, is committed to advancing technologies that enable the development of deepwater reserves. This is not surprising since 73% of Brazil's current oil and gas equivalent reserves can be found in deep water (400 m to 1,000 m) and ultra-deep water (>1,000 m). In addition, it is anticipated that 60% of all SPE 56779Case History of the World's First Level 5 Multilateral Completed from a Semisubmersible Rig

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractDespite potential and proven benefits, intelligent and multilateral wells have yet to achieve the greater-than-fiftypercent adoption level that would qualify them as truly commercialized technologies. The prevailing perception is that while these technologies hold significant potential to reduce costs in high-end, niche applications, they are too high-tech and high-risk to justify for middle-and low-end applications. The reality is that economic and production benefits exist across all types of applications, but proving it has posed a challenge.

Utilizing past multilateral installations and studies, this paper analyzes and discusses potential up front cost savings gained from a multilateral approach. Downhole savings as a result of minimized drilling requirements, reduced casing requirements, and other equipment and operations are discussed.Additional cost savings resulting from decreased surface and support requirements will are also covered in detail.Additionally, intangible cost savings in the form of reduced rig mobilization costs, lessened HSE costs and lessened rig time cost savings are included in the discussion. Introduction Multilateral systems offer a variety of opportunities for profit maximization as compared to conventional, single wellbore installations.Some of these economic benefits are easily determined while others can be more difficult to gauge.Most often, the potential advantages of a multilateral system are broken down into two broad categories.First is the ability to increase or accelerate reserves and/or production over the life of the well.Second is the ability to reduce tangible and intangible costs of the project. Either one of these may provide enough of an opportunity to justify a multilateral approach.To truly analyze the impact however, all phases of the multilateral must be considered as a whole. Certainly, the possibility of accelerating and increasing the hydrocarbon production of the well represents a significant potential benefit.When considering a multilateral approach, the reservoir and production impacts are typically the first issues discussed and tend to carry the highest priority.Recognizing the production and reservoir advantages of a multilateral well is often difficult however because this benefit is so dependent upon the targeted reservoir properties and the engineer's ability to properly model this behavior.Many times, the full reservoir benefits of the multilateral can only be determined with certainty after the well has been drilled, completed and produced for an extended period of time.This lack of certainty during the planning process makes it much more difficult in today's environment to suggest a change from standard techniques and practices. Capturing the initial cost savings of a multilateral installation in contrast, is much easier, can be determined during the well planning process and is a much more tangible economic number.And although the perception is perhaps that the reservoir is the biggest driver in a multilateral project, these tangible and intangible cost savings will certainly supplement and can easily provide the additional justification necessary to proceed with a multilateral solution. Deepwater Brazil In 1998, the first of a series of five multilaterals providing hydraulic isolation of the junction was installed offshore Brazil in a water depths of 565 meters as illustrated in Figure 1.As is typical in many multilateral considerations, the first focus and primary drivers for the project were the reservoir requirements and conditions.A reservoir study conducted in the mid 1990s had determined that in order to maintain reservoir pressures at an acceptable level, additional injection support would be necessary.Further reservoir studies had indicated that maximum reservoir exposure and sweep efficiencies could be created through the installation of a dual opposed wellbore multilateral system.