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

This paper discusses a paradigm shift in multilateral technology. The new focus is away from increasingly complex completion installations and toward simple yet highly functional multilateral completions. This paper reviews the TAML multilateral classification system, then traces Level 3 multilateral completion technology from original to current configurations. This latest iteration retains simplicity while adding full reentry functionality into both the main bore and lateral completions. The discussion then addresses pre-engineered Level 6 multilateral solutions that, by definition, uniquely embrace simplicity while providing optimal functionality. Following this discussion, case studies from Venezuela, Nigeria, and the United States illustrate installation procedures, operational issues, resulting efficiencies and economies, and opportunities to further improve the technologies. Introduction To obtain reentry and flow control in both wellbores of a multilateral application, the mindset has been to add more completion equipment for more functionality. In an effort to make multilateral risks more acceptable, Baker Oil Tools began to develop multilateral completion systems that were simpler and less risky to install. Even though there are six multilateral categories, most multilateral applications fall into two simple groups:Wells that require pressure integrity at the junction, andWells that do not require pressure integrity at the junction. For maximum functionality in both groups, the focus is on developing Level 3 and Level 6 multilateral systems that address a wide variety of multilateral well applications. TAML Classifications In an effort to provide parity when comparing multilateral systems industry wide, a classification system was developed by TAML (Technology Advancement for Multilaterals), a consortium group comprised mainly of North Sea operators. The classification system divides wells into "levels" depending upon junction functionality. Figure 1 illustrates the various level definitions1. Based on these definitions, only Levels 5 and 6 provide pressure integrity at the junction. However, Level 5 requires a complex configuration of isolation packers to isolate the junction in order to provide pressure integrity. Level 6 multilateral completions, in contrast, are much simpler in design and implementation. Levels 1 through 4 do not provide pressure integrity at the junction, and of these, only Levels 3 and 4 provide mechanical support at the junction. Note that the first Level 3 configuration did not provide a lot of functionality since a liner anchored back to the main bore limited reentry to only the lateral. As a result, one had to move up in TAML level to obtain the desired functionality of reentry into both the lateral and main bore. Technology Progression The early Level 3 multilateral well completions were constructed using a flow-through guidestock and slotted liner or screen in the lateral which was anchored back to the main bore by a liner hanger packer. Flow was allowed through the flow-through guidestock from the main bore completion, where it became commingled with the lateral production via perforations or slots in the lateral liner overlap in the main bore. The challenge was to provide a means for allowing main bore reentry. With this increased functionality, Level 3 could be a viable, simple replacement for Level 4 MLs as well as the Level 1 and 2 completions2.

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractThis paper discusses a paradigm shift in multilateral technology. The new focus is away from increasingly complex completion installations and toward simple yet highly functional multilateral completions.This paper reviews the TAML multilateral classification system, then traces Level 3 multilateral completion technology from original to current configurations. This latest iteration retains simplicity while adding full reentry functionality into both the main bore and lateral completions. The discussion then addresses pre-engineered Level 6 multilateral solutions that, by definition, uniquely embrace simplicity while providing optimal functionality. Following this discussion, case studies from Venezuela , Nigeria, and the United States illustrate installation procedures, operational issues, resulting efficiencies and economies, and opportunities to further improve the technologies.

Traditional Level 4 multilateral technology has focused on high-end applications with the intent of creating a foundation for conversion to Level 5 functionality. The Level 4 junctions are typically evaluated on three core capabilities: connectivity, isolation, and accessibility. As the evaluation criteria focuses on junction performance, little attention has been spent on reducing installation risks, junction hardware, and complexity. Recently, the effort to re-invent the Level 4 multilateral junction as a simple, low cost, low risk installation has been initiated. This new, back-to-basics approach to constructing a cemented junction has been developed by reverting to proven milling & completion techniques. This paper will introduce this new method for installing a Level 4 junction by detailing the lessons learned from a Venezuelan field trial. The paper will show how standard milling and completion techniques can be used innovatively and reliably to create simple multilateral junctions. In addition, it will explore the extensive testing and simulations needed to ensure consistent mainbore access creation while emphasizing installation simplicity. Lastly, the field trial will be compared to other Level 4 installations in the region. Introduction Definitions. As multilateral junction equipment and systems began to evolve, there was an increasing need to categorize multilateral systems industry-wide based on levels of functionality at the junction. An elaborate naming convention was developed by the consortium group: Technology Advancement of MultiLaterals (TAML), which identified the functionality level, flow control, lift mechanisms, and re-entry capability. There are essentially six functionality levels that are commonly used to describe all multilateral junctions. Only those levels discussed in this paper are defined below: Level 3. A junction where an open hole lateral is created from a cased and cemented mainbore. Screen, slotted pipe, or liner is placed in the open hole lateral and is anchored back to the mainbore by some means. This is the lowest level in which mechanical integrity at the junction may occur. Level 4.A junction in which both the lateral and the mainbore are cased and cemented. Level 5.A junction where both the lateral and the mainbore are usually cased and cemented, and the junction is hydraulically isolated using completion equipment. This is the lowest level in which pressure integrity at the junction may occur.1 The Focus The oil industry strategy has been to provide a wide variety of multilateral systems such as pre-milled windows, manufactured mainbore access windows, and completion based junction solutions. Junction construction technology has been driving the design of multilaterals industry-wide with complex hardware and methodologies. For Level 4 multilateral installations, the emphasis has been to convert the basic Level 4 to a Level 5 to provide completion based flow control and hydraulic isolation at the junction. The challenge is to provide only the functionality that is essential to meeting the minimum well requirements.2 In an effort to focus on simple, low cost, and low risk technology, Weatherford has adopted a "back-to-basics" approach to developing multilateral systems. Leveraging to their strengths as a milling company, Weatherford set out to develop a Level 4 multilateral junction using proven milling techniques and off-the-shelf components while minimizing costly completion hardware.

Horizontal sidetracking and waterflood are part of current Wafra Ratawi reservoir management strategies. These have proven successful to arrest production decline. A comprehensive surveillance program is considered to be the key to optimize waterflood performance. Saturation profile is one of critical parameters to understand waterflood sweep efficiency. The best way to acquire saturation data is by running saturation logs in vertical wells. Since horizontal sidetracking is one reservoir management strategy, the remaining vertical wells accessible for saturation logging are becoming limited and soon will not be available. This paper discusses an innovative and cost effective approach to this surveillance challenge. A combination of permanent fullbore oriented packer and retrievable whipstock, a selective re-entry system, was chosen to complete the wells. The existing vertical wellbore was converted to an observation wellbore before sidetracking. This technique has potential to save significant capital investment by using existing vertical wellbores to serve saturation surveillance purposes.Since the intent is to run saturation logs periodically in the vertical observation wellbore and to produce through the horizontal lateral during normal operation, there are several operational challenges that must be resolved. These mainly include: debris falling during ESP well services, re-entry jobs in horizontal lateral by work string, and effect of squeeze cement operation on cased-hole logs readings. This paper also discusses how the proposed completion techniques overcome these issues.Three wells have been successfully completed with this system. The first time-lapse cased-hole logs were also successfully run in one of these wells, including an attempt to re-enter the horizontal lateral by work string that went smoothly. This unique concept of saturation surveillance wellbore in horizontal producers can also be extended for new drill infill producers completed with cased pilot hole. The technique is considered to be an innovative and first time application across the globe.