chemicals used in drilling, stimulating and treating subterranean wells and formations, namely, acid corrosion inhibitors, acid systems for stimulating subterranean wells and formations, buffers, microemulsions, scale inhibitors, gelling agents for acid, anti-sludge agents, gel breakers for water and oil, clay control agents, crosslinkers, emulsifiers, fluid loss control agents, foamers, friction reducers, iron control agents, mutual solvents, non-emulsifiers, gelling agents for oil and water, anti-foamers and de-foamers, and surfactants