Proven Well Stabilization Technology for Trouble-Free Drilling and Cost Savings in Pressurized Permeable Formations

Abstract

AbstractCase studies have shown the benefits of applying a unique wellbore stabilization technology to solve lost circulation events occurring in varying pressurize, permeable, and fragile formations. Leveraging this technology can increase successful drilling in geologically complex areas while avoiding conventional solutions that are both costly and and, in some cases, do not solve the causes of non-productive time.A unique wellbore stabilization technology has been proven effective in offshore wells in areas that are known to present small vugs, natural fissures, formation failure, wellbore erosion, and the associated drilling problems of lost circulation, poor cementing quality, problems running pipe, etc. When compared with the cost and operational lack of success offered by conventional "solutions" versus the relative low-cost and operational successes of the unique wellbore stabilization technology, the choice is clear – where use is appropriate, the stabilization technology has provided a greater success rate and trouble-free drilling operations at a lower cost than traditional solutions.The unique wellbore stabilization product is designed to address microfractures (as small as 3 µm) up to much larger fractures (3,000 µm). The product can be added to oil-based or water-based fluids at functional levels without adversely impacting the fluid rheology. Once in the drilling fluid, the stabilization product forms a pressure-sensitive layer on the formation wall to isolate the drilling fluid from the wellbore and stop fluid invasion that leads to formation failure, uncontrollable lost circulation, and well control issues. Once drilling is completed, the drop in pressure differential of the wellbore fluid allows the protective particles in the drilling fluid to lift off with the initiation of production. In the Campeche wells, one early study showed a 36% reduction in drilling time and 24% reduction in cost.This paper discusses the various options explored and detail the technical analysis that preceded the application of the wellbore stability technology. Case studies are presented to illustrate the effectiveness of the fluid technology in drilling three wells which encountered variable pressure regimes, from the highly pressurized Paleocene at around 5,000 m to underlying low-pressure sandstones. These three wells and their offsets represent the successful application of this low-invasion technology in major drilling basins where lost circulation events would normally incur major operational expenses and non-productive time (NPT).