Smart Nanostructured Materials Deliver High Reliability Completion Tools for Gas Shale Fracturing

Abstract

Abstract Hydraulic fracturing is considered necessary for economically efficient gas production in low natural permeability shale resources. Flow control devices such as setting balls or plugs are used for sleeve actuation or stimulation diversion during fracturing. After fracturing, these in-flowpath devices must be disposed of by methods such as drilling out or flowing back to open the flowpath for production. Traditional low-strength ball or plug materials are prone to shape changes. Severe deformations present flowback issues and potentially require costly intervention. Additionally, it is believed that smaller balls—particularly from the well's toe section—do not always flow back to surface, leading to potential restrictions in the tubing. Operations value the concept of fully degradable ball material. Traditional degradable material, though, lacks the high material strength necessary for high-pressure fracturing and has unreliable degradation rates. This paper will present a newly-developed nanostructured material technology called controlled electrolytic metallics (CEM), which makes high-strength and lightweight metallic composites possible. This new class of composites is completely corrodible in typical downhole environments at a predictable and controllable rate. CEM balls have passed multiple impact tests at speeds exceeding 100 mph. In 3% potassium chloride (KCl) at 200°F, these balls can completely corrode away in-situ in days. Material composition and associated processing can be changed to increase material strength by several times and the corrosion rate by several hundred times. CEM balls performed as designed in Bakken shale field testing. Material can be designed to rapidly corrode in 5 to 15% hydrogen chloride (HCl), giving a foolproof technology with operational flexibility. The fundamentals of innovative material design and processes, along with lab test and field application data of this material will be presented. CEM-based completion tools eliminate drilling out, guarantee an open flow path for each fractured zone, and enhance well productivity. This truly interventionless technology is also being researched for high-pressure, high-temperature (HP/HT) applications.