Over the past decade BP's primary sand control techniques have been dominated by Frac Packs in the Gulf of Mexico and Open Hole Gravel Packs (OHGP) and Stand Alone Screens (SAS) in the rest of the world. In 2003, BP formed a collaboration agreement with Weatherford to develop a new Expandable Reservoir Completion (ERC) system. The collaboration aimed to develop a cost competitive high performance sand control system, which would provide open hole productivity with cased hole functionality in an 8 ½″ open hole. The system would be run and expanded in a single trip to ensure efficient installation, an essential requirement in making the new system competitive with more established sand control technologies in high cost environments. BP's Exploration and Production Technology Group (EPTG) together with several Business Units, supported the development of this new ERC System. Through the initial development phase from 2004 through 2006 a total of 5 installations (3 producers, 1 injector and one Stack up Test) have been completed to test the functionality of the completion equipment and associated expansion tools. This paper will describe the development of the ERC system and review some of the most significant lessons learned during the qualification testing and field trial installations. Careful documentation of all preparation and installation activities has been supplemented by focused data acquisition during installations. Recording high resolution borehole images and caliper data and critical downhole expansion parameters has allowed detailed post job analysis capability. Subsequent well performance data has also been used in evaluating completion durability and effectiveness. The complications associated with combining single trip functionality with rotary expansion and the importance of the well trajectory with respect to downhole torque will also be discussed. The data collected will show the new 7″ ERC system has to date provided comparable sand control and productivity / injectivity performance when compared to other well established sand control techniques. Introduction In early 2000, BP recognized the potential value that expandable "screen" technology could bring to its operations. In 2002 BP initiated a technology development project based around an expandable "completion", not just an expandable screen. There were three major themes surrounding the development of this technology: The technology would be required to deliver good sand control with high reliability and assured completion integrity. Productivity would have to be equal to or better than existing cased or open hole completions. Efficient deployment that matched or improved on existing sand control techniques with minimal operational risks was targeted. The expandable completion would have the ability to allow conventional reservoir surveillance. It would also incorporate the option of zonal isolation and provide the potential for integrating intelligent well technology should it be desired. This feature provides a significant benefit with respect to reservoir management.

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Sand production is becoming increasingly problematic due to the exploitation of poorer quality reservoirs and depletion of existing reservoirs. Cased hole frac-packs (CHFP) combine reliable sand control with potential for high productivity, and have become the completion of choice in many provinces. However, CHFP completions manifest in limited flow entry area into the well. This may cause two problems; a loss of productivity and potential screen erosion. In CHFP designs it is common to perforate the casing with high shot density big hole charges, but due to shot orientation and phasing, only a relatively few perforations connect with the fracture. Entire well production therefore originates from 4spf or less. Detailed modeling shows that this will not cause productivity impairment if the proppant pack is undamaged. Predicted skins for undamaged CHFP should be slightly negative, but field observations in one particular region show typical skins of 2 to 5, but with skins above 10 also reported. This tends to suggest that proppant permeability is being reduced in-situ. By contrast, productivity of open hole frac-packs (OHFP) is significantly less impacted by proppant damage and they also greatly reduce screen erosion risk. The productivity enhancement is revealed through detailed inflow modeling and laboratory experiments. However, it is difficult to engineer multi-zone OHFP completions, and wellbore stability issues complicate implementation. These limitations can be resolved by setting field-proven expandable completion liner (ECL) in the openhole section, prior to running the inner sand screen completion and frac-pack tools. Experiments on large scale samples show that ECL stabilizes the borehole. ECL slot geometry also results in 3-5 fold increase in fracture connection area compared to CHFP. ECL technology can also be combined with a number of different zonal isolation packer technologies, such as expandable, mechanical, swell and combo packer designs, to segment zones. This gives ECL frac-packs (EFP) the functionality of a multi-zone CHFP, but mitigates productivity impairment through proppant plugging and also screen erosion risk. The EFP completion concept also removes a casing string and eliminates perforating, and so also reduces HSE risks. It also has the potential to accommodate larger screen sizes, slim well designs and to reach deeper targets. The EFP completion concept also relies on integration of existing technologies, while offering the potential for a step change in well performance.