chemicals for use in oil well drilling fluids; chemicals for use in cement; chemicals for use in mining; chemical additives for use in oil and gas; chemical additives for use in oil well drilling fluids; chemical additives for use in drilling muds; chemical additives for use in determining the presence of oil, gas, or minerals in a sample; chemical additives for use in cement; chemical additives for use in mining; chemical additives for use in the oilfield service industry, namely, the petrol...