A Unified Approach to Well Integrity Evaluation Led to Better Decision Making for Workovers in Mature Wells in the Waddell Ranch, West Texas

摘要

The often referenced Norwegian standard D-0101 describes well integrity as the ―application of technical, operational and organizational solutions to reduce the risk of uncontrolled release of formation fluids throughout the life cycle of a well". Well integrity can therefore be considered in terms of the structural soundness of the well, its casing, cement and wellhead; and how it reduces the risk of the uncontrolled flow of formation fluids to other formations or surface. Well integrity is a critical issue when working over and recompleting mature wells. This paper describes common integrity issues and develops a workflow for managing well integrity information during the design, execution, and evaluation of workover operations. It was found that no one measurement can give a complete well integrity analysis; instead a unified systematic approach considering a variety of measurements will lead to successful, economical, and well executed workovers. There is a great deal of value in obtaining certainty about the status of a wellbore from a clear logging and testing regime. The type of logging package will depend on the economics of the recompletion campaign, but the cost of logging operations pales in comparison to a lost hydraulic fracture or series of expensive squeezes. The evaluation and quantification of workover rates, reserves and economics in this field are not within the scope of this paper, and will not be addressed here.