Case Study of Section Milling Run in Abrasive Salt Dome Formation and Technological Development for Multi-String Section Milling

Abstract

The Stratton Ridge salt dome located in Brazoria County, Texas, has been used extensively by industry for brining operations and for the storage of liquid hydrocarbons, refined products, and natural gas. The shape of the dome has been defined by several hundred oil and gas wells drilled over the top of this highly anomalous geologic diapir structure. Cavern operations at Stratton Ridge historically are known to have experienced a number of problems. These difficulties and "off-normal events" include severe lost circulation while drilling through cap-rock, sheared well casings, corrosion, shifting, and encountering hydrocarbon products that appear to have escaped from the storage cavern.

This paper describes a case study of section milling in the gas storage cavern of this highly abrasive salt dome, the challenges faced, and how the challenges were detected and overcome. The unique aspect of this case study is the introduction of new section milling technology. New technologies in multiple-string section milling plays an important role to improve operational performance, reduce costs, and eliminate NPT—especially in the current global environment of low oil prices. This paper also touches the R&D development for multi-string section milling in various settings.