The following will outline the Medusa Field development and completion design process highlighting an integrated approach between engineering disciplines and service providers to exploit the enormous amount of exploratory well data. The Medusa development, located in Mississippi Canyon blocks 538 and 582 offshore Louisiana, is a truss SPAR allowing for both dry tree production and multiple subsea tiebacks.A field overview from a geological and reservoir perspective, along with the drilling and field development considerations, will be summarized. The initial phase of the Medusa truss SPAR development includes ten compaction-tolerant FracPac completions in six dry-tree wellbores.Phase II wells included the drilling of two subsea tiebacks.One was drilled and deemed uneconomic while the second, Medusa North, was completed and tied back in early 2005. The paper will show how the information gathered during the drilling phase was applied to the completion design to ensure long-lasting, reliable and profitable wells. Introduction Design of deepwater completions requires a vast amount of planning and communication between all involved engineering disciplines. Bridging the gap between petrophysical, drilling, completions, and operations is imperative to obtaining project profitability through efficient, long-term and robust completions. Mechanical integrity is crucial to any completion design.Deepwater and subsea completions command very high production rates and can require fewer wellbores to develop a field.Add to this the high cost of well intervention and efficient, dependable wells with stacked pay horizons become the primary driver to economic deepwater Gulf of Mexico field development. The quality of a deepwater completion relies heavily on the proper use of reservoir data gathered during the drilling phase.Since it has a direct bearing on the efficiency of the completions, accurate analysis and use of this reservoir data must occur subsequent to the drilling phase.In particular, fluid samples, core samples, and logging data are all imperative. Field Overview The Medusa development, under Mississippi Canyon blocks 538/582 in the Gulf of Mexico, is about 100 miles south of New Orleans, Louisiana in about 2,200-ft of water (Fig. 1). The Medusa prospect originated from the drilling of two exploratory wells from a semi-submersible rig beginning in August 1999.These wells were sidetracked to further delineate the field and gather valuable core, fluid and logging data.Upon drilling of the discovery wells, an evaluation period followed in which economic decisions were made. Once field development was sanctioned, a development drilling program was initiated.Simultaneously, the design and fabrication of the truss SPAR production facility began. Medusa Field Development Timeline 08/99 - Spud Discovery Well 10/99 - Discovery Announced 05/00 - Delineation Drilling Complete 03/01 - Contract Awarded for Floating Production System 07/01 - Development Drilling Begins 03/02 - Development Drilling Complete 02/03 - Hull Installation 05/03 - Topsides Installation 07/03 - Topsides Commissioned 09/03 - Initial Completion 11/03 - First Oil The time from the end of the drilling phase to the commissioning of the production facility was used to analyze all available reservoir data and explore various completion techniques.From this analysis, mechanically sound, high-rate completions were designed and a reservoir depletion plan was developed to efficiently produce the hydrocarbon reserves from the multiple sands in the field.

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Optimizing the design of injection processes in sand control (i.e., conventional gravel pack and frac-pack) and stimulated completions as well as in injection wells has been a primary goal in selecting methods to improve cost and operational efficiency. It is well accepted that perforating with shaped- charge jet explosives has had a large impact on the efficiency of oil and gas completions in cased wells. However, accurate predicting of the impact of different perforating systems or operations can be difficult, as there are many variables in the process that can not be easily quantified; therefore, modeling the detailed physics of the process is complex. This paper examines perforating as it relates to injection wells and/or injection processes. Experiments using field shaped-charge explosives were conducted under a variety of conditions with different cores to quantify injectivity compared to productivity. Results from the laboratory experiments were then compared to field data for validation. New knowledge and insights are gained to better understand and to optimize the design of injection processes in sand control completions and completion processes in injection wells. Introduction The impact of perforating systems (i.e., both hardware and operating conditions) on well performance has been well researched and documented1–3. Theoretical models,4–6 experimental data,7–8 and field studies9–10 have sought to optimize well productivity or injectivity by quantifying the relationships between well inflow performance and key perforating/reservoir parameters. However, there are relatively very few studies that focus specifically on injection, with most of these focused on field-specific injection problems.11–13 The limited focus on injectivity wrongly implies that it is identical to productivity and/or not of value. Water injection is critical to maintain reservoir pressure, and optimized well performance is valuable because there are relatively fewer wells dedicated to this task. Furthermore, injection processes are prevalent in completions requiring acid and fracture stimulation and sand control. Most studies on injection damage focus on the importance of quantifying the injection fluid and rock interactions.14 Halleck et al.15 conducted an experimental study of perforating mechanical damage, measuring the rock hardness of the zone damaged by a 6.5 gm explosive shaped charge in three different cores. Blok et al.16, Wong et al.17 and Welling18 conducted experimental and field studies that related perforating and sand control completion damage. These studies confirm that there is much need for the integrated design of the perforation and completion systems to deliver optimized well performance in cased wells. This paper details a perforation study that was performed to understand the damage mechanisms associated with injection wells and/or injection processes. In particular, it looks at how perforating charges and practices affect the capability to inject fluids based on several series of API RP19B19 Section IV flow tests performed in Berea and Castlegate sandstones. The experimental study simulated a range of gun and shot conditions from perforating underbalanced using tubing-conveyed guns to perforating overbalanced with wireline-conveyed guns in moderate-to-high permeability core samples. Results were then compared to case history data to validate damage mechanisms in field injection processes and to develop understanding of how the design of perforation and completion processes in sand control, stimulated and injection wells could be optimized.