TX 75083-3836 U.S.A., fax 01-972-952-9435. AbstractThis paper describes the application of Sand Control Screens coupled with Inflow Control Devices (ICDs) in the Troll Oil sub sea field development.Technical and functional description, qualification, computer modeling and production experience verifies that completions with ICDs yield higher volumetric recovery of oil from each well compared with more conventional sand control completion methods. Improved sand control results from the screen systems inflow distribution functionality.

This paper discusses developments in horizontal well completion practices. During recent years, the pursuit of screen based open hole completions with zonal isolation in deviated and horizontal wells has fostered the development of new technology, new applications, and processes to improve recovery of oil and gas. Based on case histories, computer simulations and laboratory testing, this paper describes recent findings which have lead to revisions in completion design and operating best practices. Introduction Since the initial horizontal reservoir sections were drilled in the early 80's both drilling and completion methods and technologies have experienced dramatic changes and a diverse range of techniques, applications, and equipment have emerged. Most sandstone reservoirs are related to specific sandstone failure mechanism, which in turn derives the requirement for sand management. Managing the sand production related problems often means retaining the sand down hole, without jeopardizing the wells productivity. This combined with the ability to increase the drainage area in the oil or gas bearing sands, or the desire to reach multiple targets with one well, has derived strategies of:Longer horizontal sections, maximizing reservoir contact per well.Multi zone completions, draining multiple reservoir segments.Multi lateral completions, reaching different parts of the reservoir. (Figure 1)Intelligent Well Systems (IWS) providing remotely operated zone control and monitoring. Applying these technology advances have yielded increased oil recovery[1]. Combating the potential sand production, downhole sand management techniques where developed. They include:Open Hole Horizontal Gravel PacksStand Alone ScreensStandalone screen with Inflow Control Devices.Formation packers for reservoir compartmentalization.Expandable screensCased hole selective perforationCased hole oriented perforations For some regions and operator practices cased hole frac packs have become a viable default when the above mentioned methods yields undesired performance in terms of productivity and completion longevity. All but one of the above mentioned completion techniques have a common challenge or deficiency. Unless there is severe damage to the completion, they all appear transparent to flow. Screens, gravel packs even perforations represents only a negligible resistance to flow when designed and installed correctly. This is what most completion design-projects aim for.

This paper focuses on the first global installation of a water injector well with a lower completion system that incorporates both premium sand control screens and water injection profile equalization. The equalization of the water injection profile of horizontal wells has been a key issue in many development projects worldwide and has the potential to increase the reservoirs ultimate recovery by increasing the water sweep efficiency. Inflow Control Devices integrated with premium sand control screens have a long history of application in production wells. In these cases the main objective is to create a uniform inflow profile along the horizontal section, delaying unwanted water and gas production and increasing oil recovery. The method through which Inflow Control Devices equalize the inflow of oil can also be used to equalize the outflow of water. Historically, sand control completions for water injection wells include stand-alone conventional screens and open-hole gravel packs. Stand-alone conventional screen completions do not provide equalization of the water injection profile. Open-hole gravel packs provide for an effective acid treatment of the water injector well but present operational risks, high costs, as well as expensive rig time. The installation was carried out in a subsea horizontal sea water injector well in the Campos Basin, offshore Brazil. The paper presents the overall completion plan, the lower completion installation, the acid treatment through the Inflow Control Devices, and the initial water injection results based on production logs and water injectivity tests. The main concerns during the planning phase are discussed, highlighting the procedures adopted to overcome them. The good initial results have created the expectation of many applications of this system in Campos Basin. It is believed that sharing this information will benefit many operators with horizontal water injectors in their field development plans. Marlim The Marlim field, located in the northeastern part of Campos Basin, about 110 km offshore in the state of Rio de Janeiro, was discovered in January 1985. The field covers an area of about 145 km2, in water depths ranging from 600 m (1968 ft) to 1,100 m (3609 ft). The Oligocene sandstone reservoir quality is good. Core analyses of several wells indicate mean permeability of 2,000 md, mean porosity of 30%, and highly friable sandstone. Marlim's reservoir development strategy relies heavily on water injection as a source of reservoir energy maintenance. Currently 9 Floating Production Systems (FPS) are on stream with 129 subsea wells on operation (83 producers and 46 water injectors), including 36 horizontal wells. The total production reached its peak of 650,000 bbl/d in 2002, overcoming all former production forecasts. Currently Marlim field oil production, around 450,000 bbl/d, is supported by injecting 760,000 bbl/d of sea water. The recovery factor to date is 22.9 %. The water production is 217,150 bbl/d (water cut of 33 %) and GOR is equal to the initial solubility ratio, 83 STD m3/STD m3. Water injection is into the oil leg, concentrated in the lower portions of the reservoir and production is concentrated in the upper parts, to delay water breakthrough. A thorough history of the Marlim field can found in references 1 through 6. Injection Well Strategy The water injector well under consideration for this project was to be located in the south area of the Marlim field. This injector well was planned for pressure maintenance and for sweep efficiency in the thin reservoir border of the field. The injector well, IN, and its neighboring producer wells, A, B, C, and D are shown in Figure 1.