TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractMultilateral technology offers the oilfield many advantages since it can deploy a completion system that can mechanically connect several lateral wellbores to a parent wellbore and will allow selective or commingled production. In most cases, these capabilities can provide more cost-effective well construction since reservoir exposure from one wellbore is increased. These advantages are particularly beneficial in offshore and deepwater environments where slot and/or subsea templates are limited, and rig costs are substantially higher. Because of the flexibility of this technique and its capability to offer various production options, it helps to mitigate the risks previously associated with directional/horizontal wells in new field developments as well as in revitalization of mature fields. Because of continual improvement in drilling techniques and the increase in field success, multilateral technology continues to gain in popularity; however, as with all completion techniques, it must be remembered that existing completion options must be evaluated for each case, and if needed, adapted to meet specific reservoir objectives and concerns. This paper will focus on considerations, applications, and benefits of specific tool configurations developed for interfacing sand-control fracturing stimulation with multilateral technology. The techniques discussed include existing, modified, and conceptual completion methods that can be deployed into multilateral field-development strategies. The strategies address window selection, junction isolation, fluid loss, debris management, and lateral accessibility. Several completion sequences, which include a new Technology Advancement for Multi-Lateral (TAML) level 4 single-trip, gravel-pack methods and installation of expandable screen technology, will also be presented.

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A visualization software tool has been developed to aid in the analysis of the numerical output generated by a 3-D gravel pack simulator. The tool provides animated 3-D graphics showing the condition of moving fluids and the progress of gravel placement within the wellbore. The advantages, limitations, and pitfalls in implementing the 3-D visualization for analysis of gravel pack simulation results are addressed.

Economic efficiency in today's oil and gas industry requires careful consideration of all horizontal openhole completion criteria during the completion design stage. This paper will review the scenarios that can limit the success of openhole horizontal completions and will focus on problems inherent to sand-producing reservoirs and their management using 1) prepack screens available today and new screen design innovations, 2) recent 90-degree short-and long-radius screen bend tests that determine flexibility characteristics, 3) mechanical fluid-loss control systems, 4) circulation options available to the operator for openhole cleaning 5) and new innovations in zonsl isolation with sliding sleeve circulation devices that address sanding problems.Case histories of several unique completions that proved to be successful in controlling premature water breakthrough and sand problems in fractured reservoirs will be presented, followed by a summary of the important considerations for openhole horizontal completion design.

Multilateral technology offers the oilfield a completion system that mechanically connects one or more lateral wellbores to a parent wellbore and allows selective or commingled production. These capabilities usually provide more costeffective well construction since reservoir exposure from one wellbore is increased. In offshore and deepwater environments where slot and/or sub-sea templates are limited and rig costs substantially higher, these advantages are even more beneficial. Because of the flexibility of this technique and its capability to offer various production options, it helps to mitigate the risks previously associated with directional/horizontal wells in new field developments as well as in revitalization of mature fields. Continual improvement in drilling techniques and the increase in the number of field successes using multilateral technology have continued to increase its popularity; however, as with all completion techniques, it must be remembered that existing completion options must be evaluated for each case, and if needed, adapted to meet specific reservoir objectives and concerns. This paper will focus on interfacing sand-control fracturing stimulation with multilateral technology. The techniques targeted include existing, modified, and conceptual completion methods that can be deployed into multilateral field-development strategies. The strategies address window selection, junction isolation, fluid loss, debris management, and lateral accessibility considerations along with the applications, and benefits of specific tool configurations recently developed. Several completion sequences, which include a new Technology Advancement for Multi-Lateral (TAML) level 4 single-trip, gravel-pack methods and installation of expandable screen technology, will also be presented. Introduction The benefits of multilateral technology have been well documented around the world as a cost effective alternative to accessing oil and gas reserves. To date, the bulk of these installations have occurred in naturally fractured carbonate reservoirs as well as poorly consolidated sandstone reservoirs. In either scenario, the lateral borehole typically is drilled horizontally so that maximum reservoir exposure can be obtained. Slotted liners or sand screen completions have been very effective for borehole support and/or sand-control devices when deployed in uniform sandstone reservoirs,1 whereas openhole completions are commonly used in carbonate reservoirs with natural fractures. Fracture stimulation and advanced sand control completion applications can also be implemented into multilateral well planning strategies. Low-perm carbonate reservoirs can be effectively stimulated using traditional stimulation designs normally performed in single wellbore applications. The junction isolation tool configuration will vary and depend predominately on the TAML classification of the junction as well as whether the stimulation job is pumped down the casing or the tubing work string. In addition to isolating the junction from the stimulation-treating pressure, the tool configuration should also have capability to provide well control and zonal isolation. This will allow multiple lateral legs to be individually stimulated from a single parent bore and will eliminate the need for kill-weight fluids after each zone is stimulated and unloaded. In sandstone reservoirs that require gravel packing or fracand-pack applications, the completion tool configuration for the mainbore and lateral completions will differ. The mainbore completion below the junction can normally deploy traditional sand-control equipment.