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

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.

Smart Gas Lift Valves Eliminate Multiple Slickline Trips in Gas Lift Operations

“…4 is a typical scanning electron micrograph of the NCM material, which includes a substantially continuous, cellular nanomatrix (networked white grain boundary phase) and metallic grains dispersed in the nanomatrix [3]. The NCM material encompasses a unique microstructure.…”

Smart Gas Lift Valves Enhance Operational Efficiency of Offshore Wells

“…The image on the left of Fig. 3 is a typical scanning electron micrograph of the NCM material, which includes a substantially continuous, cellular nanomatrix (networked white grain boundary phase) and metallic grains dispersed in the nanomatrix [3]. The nanomatrix consists of nanoscale metallic and/or ceramic layers/coatings that act as reinforcements for high strength as well as to provide the unique chemical property that gives the time-controlled disintegration property that conventional engineering materials normally do not have.…”

Study and Field Trials on Dissolvable Frac Plugs for Slightly Deformed Casing Horizontal Well Volume Fracturing

“…In 2014, CNPC alone spent 70–90 million RMB on drilling and plugging, and the large amount of drilling and plug residues caused by wellbore plugging has a great impact on production. In 2010, based on the research and development of dissolvable magnesium-based materials − and aluminum-based materials, the research of frac plug was conducted from drillability to self-solubility. At the end of 2015, the study of dissolvable frac plug − and the field test were started.…”