Research and development, sales, and leasing of petroleum drilling and production tools, equipment, and accessories; technical services, technical consultation, technical development, and technical transfer for petroleum drilling and production; well completion services; technical research, design, and services for solid waste and wastewater treatment equipment and accessories; design, manufacturing, sales, leasing, technical services, and tank cleaning services for tank cleaning equipment; research and development, manufacturing, sales, leasing, and after-sales services for environmental protection equipment; soil remediation services; treatment of sewage and sludge; maintenance, technical services, and sales of oilfield equipment and accessories, and specialized industrial equipment and accessories; labor subcontracting; production, processing, manufacturing, and sales of mechanical equipment; acidification and fracturing, coiled tubing solution design, construction, and technical services.