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.