THWRC Awarded Proposal 515UHH0049H

Project Number:       515UHH0049H

Title:                           Understanding and Controlling Radioactive (Ba, Ra) SO4 Precipitation on Oil-field

                                     Equipment

Lead PI:                     Yandi Hu

Awarded Amount:    $27,500

ABSTRACT

Barite (barium sulfate, BaSO4) scale formation on oil-field equipment can cause production efficiency decrease, production equipment failure, and even emergency shutdown. Also, barite can incorporate radioactive radium (Ra) in its structure and form (Ba, Ra)SO4, which is the primary host of oil-field naturally occurring radioactive materials (NORM). Once barite formed on oil-field equipment, its removal can be very expensive and can cause radioactive exposure to the workers. Especially for Texas, radioactive (Ba, Ra)SO4 scale formation on oil-field instrument has been, and will continue to be, an essential problem which requires new solutions. Polymer inhibitors have been injected to reservoirs to inhibit barite crystal growth in solution; However, controlling heterogeneous (Ba, Ra)SO4 precipitation on equipment, which involves various interactions among the aqueous species, barite crystals, and instrument surfaces, are not studied yet. Here we propose to coat the equipment with well-designed self-assembled monolayers (SAMs), which will alter the physicochemical properties of the equipment surfaces and will therefore inhibit heterogeneous (Ba, Ra)SO4 precipitation on equipment. Stainless steel coupons, which represent equipment surfaces, will be coated with common SAMs (i.e., –CH3, –OH, –SH, or –COOH terminated SAMs), and the performance of the SAM coatings on preventing (Ra, Ba)SO4 precipitation on the coupon will be quantified and compared under varied aqueous conditions (varied ionic strength, Sr2+, Ra2+, Ba2+, and SO42- concentrations, and in the presence of organics). To understand the underlying mechanisms, solution–barite–substrate interactions will also be investigated using multiple interfacial characterization techniques. At the end of the two-year project costing a total of $50,000, optimized SAM coatings will be designed for the first time. The proposed research will establish a foundation for using SAM coatings to prevent barite precipitation and radium accumulation on oil-field equipment surfaces, which are important for safer and more efficient oil production. Furthermore, the methodology and knowledge can be translated to control heterogeneous precipitation of other minerals on operation equipment in many industrial processes.