RESULTS OF BIOSTABILITY TESTING OF SOME ACRYLIC-BASED ADDITIVES IN THE DRILLING WATER

Abstract

The conventional process of drilling oil and gas wells uses a rotary drill bit that is lubricated by drilling fluids or muds. As the drill bit grinds downward through the rock layers, it generates large amounts of ground-up rock known as drill cuttings. Drill cuttings are made up of ground rock coated with a layer of drilling fluid. Drilling fluids or muds are made up of a base fluid (water, diesel or mineral oil, or a synthetic compound), weighting agents (most frequently barium sulfate is used), bentonite clay to help remove cuttings from the well and to form a filter cake on the walls of the hole, lignosulfonates and lignites to keep the mud in a fluid state, and various additives that serve specific functions. Most water-based muds are disposed of when the drilling job is finished. In contrast, many oil-based muds and synthetic-based muds are recycled when possible. Sometimes the physical and chemical properties of the used muds have degraded somewhat, and the muds must be processed to rejuvenate the necessary properties. Choosing the right organic additive to the drilling water as to protect of the environment we should take into consideration its experimental data of the biodestruction. Biological destruction research of the most common drilling acrylic-based reagents identified significant biostability of wasted drilling partially hydrolyzed polyacrylamide, hydrolytic polyacrelamide and polyacrylate of sodium. The evaluation of phytotoxicity of acrylic-based drilling reagents derivatives shown that the inhibitory polymer effect decreases with their biodegradability and products accumulated are not phytotoxic.