Fosfomycin and Its Derivatives: New Scale Inhibitors for Oilfield Applications

Aminomethylenephosphonate-based scale inhibitors (SIs) have been widely studied and recognized for several decades to mitigate various oilfield scales. However, most of these compounds afforded several drawbacks, such as poor biodegradability and intolerance with the production system. As environmental regulations become more rigid, new production chemicals must adhere to certain criteria to qualify for use in the oil and gas industry, particularly in areas with strict regulations, such as the Norwegian Sea. The low toxicity of fosfomycin encouraged us to test fosfomycin and related molecules as new aminomethylene-free phosphonate SIs for calcite and gypsum scales. The tested chemicals are fosfomycin disodium salt (SI-1), fosfomycin trometamol (SI-2), and hydrolysis of fosfomycin called 1,2-dihydroxypropyl phosphonic acid (SI-3). The inhibition efficiency of all these chemicals was evaluated against calcite and gypsum scales compared to commercial oilfield scale inhibitor hydroxyphosphonoacetic acid (HPAA) according to the NACE Standard TM0374-2007. In addition, the calcite scale inhibition efficiency of all aminomethylene-free phosphonate SIs (SI-1 to SI-3 and HPAA) was investigated based on the Heidrun oilfield, Norway. Moreover, we have reported the calcium compatibility of these chemicals at various concentrations of SIs and calcium ions at 80 °C over 24 h. All new aminomethylene-free phosphonate SIs showed good gypsum and calcite inhibition performance. It was also found that all tested chemicals derived from fosfomycin demonstrated excellent compatibility with calcium ions of up to 1000 ppm throughout the 24 h experiment period compared to HPAA.