A Novel Approach and Application to Dual String Design in Smart Well Completion

Abstract

Completion design is a very important phase in the development of a field, and it has evolved over the years with more sophisticated technology. One of the latest technology trends is the Intelligent Digital Oil fields, which although started decades ago has recently received rapid traction in past few years due to reduced costs and improvement in sensors and data storage. The starting point of this technology is the smart or intelligent well system (IWS). This system significantly improves reservoir management as it enables remote control and monitoring of downhole equipment’s. Consequently, this minimizes the need for any intervention and saves OPEX. However, the IWS has majorly being applied to a single string producer or injector. Previously, a single string completion is used across the multiple zones and hence must be commingled if the zones are to be produced simultaneously. The alternative to produce simultaneously without commingling is to use Dual string completions but they have a major drawback in that they always require some intervention to be done which is expensive. The aim of this project is therefore to test a novel idea of combining a Dual String completion with an Intelligent completion. A hypothetical field with three reservoir zones stacked was used for this study. The objective was to produce the lower zones through the long string as they had similar reservoir pressures and compatible fluids while the upper zone would produce through the short string as it is incompatible with the lower zones. Two cases were considered – with and without lower completions. The major difference in these cases was the position of the accessories. The adopted design uses a feed-through dual packer, two ICVs, and a dual gauge on the long string above the gravel pack packer and on the short string, a permanent gauge is placed above the feed-through dual packer and a total of 6 control lines is required. It is concluded that the design is feasible in both cases, and it solves the short comings of the dual string completions currently being used. The critical consideration is the well architecture. The knowledge from this paper serves as a foundation for what could become a new standard design for smart completions.