Optimized Well Design on Brage
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Slot recovery operations have the intention to increase the oil recovery and extend the lifetime of maturing fields. Keeping the well cost low is an important aspect of such operations, as the recoverable resources are minimal compared to virgin reservoirs. Well costs are highly dependent on time consumption, and avoiding non-productive time is therefore a key success factor. Hole stability challenges are a major contributor to non-productive time, and an optimized well design could therefore be considered as a design that makes it possible to avoid instabilities. This report has through a comprehensive study of the wells drilled on the Brage field proposed solutions to the hole stability challenges experienced on the field to avoid lost hole section and reduce the non-productive time. All the wells drilled on the Brage field from the discovery in 1980 until today have been studied, and some of the wells are evaluated in depth in this report. The proposed optimization of well design in mainly based on previous experiences regarding mud weight, inclination through difficult formations, direction of the well path and drilling practices.The major contributors to the instabilities experienced on the field is found to be poor hole cleaning and drilling practices, together with incorrect mud weight and inclinations through some of the formations. A simplified system for experience reporting have been suggested, together with a dedicated hole stability experience database, to improve the efficiency of the well planning phase and the result of future well operations. Some technologies have been proposed to be implemented to the well design or continued to be used. Before a final conclusion on the advantage of these technologies can be made, an evaluation of the benefit versus the cost must be carried out. In this report, optimization of the conventional well design is therefore considered as the best solution for the Brage field.