System, Apparatus, and Method for Utilization of Bracelet Galvanic Anodes to Protect Subterranean Well Casing Sections Shielded by Cement at a Cellar Area

摘要

A cathodic protection system is provided for a subterranean well casing having an enclosed upper section of the well casing being substantially shielded by a cellar from an impressed-current cathodic protection circuit passing through earth media. The impressed-current cathodic protection circuit is provided to protect an unenclosed lower section of the well casing. To protect the enclosed upper section of the well casing, a supplemental cathodic protection circuit is provided. The supplemental cathodic protection circuit is a galvanic anode cathodic protection circuit comprising the enclosed upper section of the well casing and one or more bracelet galvanic anodes being circumferentially mounted to the enclosed upper section. The enclosed upper section of the well casing and the one or more bracelet galvanic anodes are substantially surrounded by a cellar backfill, and the galvanic anode cathodic protection circuit is equally effective throughout a broad range of non-homogeneity within the cellar backfill.

主权项

1. An enhanced cathodic protection system for a subterranean well casing having an upper vertical well casing section thereof in a cellar area and one or more lower well casing sections below the cellar area, the cellar area being bounded by a cellar ring, the vertical well casing section in the cellar area defining a cellar-area well casing, the enhanced cathodic protection system comprising:
an impressed current cathodic protection system comprising a subterranean anode bed surrounded by a ground electrolyte in communication with the one or more of the lower well casing sections, the subterranean anode bed adapted to provide a first ion pathway through the ground electrolyte to the one or more of the lower well casing sections, the subterranean anode bed further being electrically connected to the subterranean well casing through one or more cables and one or more cathodic protection rectifiers to provide a first electron pathway to the subterranean well casing, the impressed current cathodic protection system providing primary cathodic protection to the subterranean well casing; and an enhanced galvanic anode cathodic protection system comprising one or more bracelet anodes being circumferentially mounted to the cellar-area well casing and being surrounded by a cellar electrolyte, the cellar electrolyte being bounded by the cellar ring and also surrounding an outer surface of the cellar-area well casing, the one or more bracelet anodes circumferentially surrounding the cellar-area well casing and providing a second ion pathway through the cellar electrolyte to the cellar-area well casing, the one or more bracelet anodes further being electrically connected to the cellar-area well casing through one or more shorting screws to provide a second electron pathway to the subterranean well casing, the enhanced galvanic anode cathodic protection system providing secondary cathodic protection to the subterranean well casing.