【Ten Years of Great Progress in Chemical Engineering Technology】International Advanced Core Technologies for the Treatment of Waste Liquids from Oilfield Operations from 2020 to 2022
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Ten years of rapid development in chemical engineering technology; praise for the prosperous and strong China. This is just a starting point to encourage more participation from everyone. HaiChuan becomes even better with your involvement – we welcome all to join in the forum discussions. The fragrance of rice flowers in August -----------------------------------------In December 2022, the “high-salinity water-based drilling fluid/drill cuttings treatment technology for oil fields,” developed by CNOOC Safety and Environmental Protection Company, successfully passed the evaluation conducted by an expert panel organized by Tianjin Technology Property Exchange Co., Ltd. This technology was deemed to be of “internationally advanced” level. The technical team took the challenges associated with the disposal of drilling waste fluids as its goals for research and development. It successfully overcame the technical barriers related to the difficult task of collecting and discharging such waste fluids in a compliant manner, establishing a complete process for dealing with drilling waste fluids and fracturing return fluids. This approach effectively resolved various technical issues encountered in the treatment of drilling waste fluids, including gel breakdown, multi-metal catalytic oxidation of fracturing return fluids, and MVC evaporation crystallization for high-salt waste fluids. The team mastered the core technologies needed to handle complex waste fluid streams generated during oilfield operations, thereby enabling standardized and centralized disposal of these waste fluids
Technological innovation 1: Broad-spectrum composite demulsifier for saline drilling fluid systems. To address issues such as high amounts of water-soluble polymers in drilling waste fluids, which make demulsification difficult; high salt content that hinders flocculation; and high oil content that causes clogging of the filters used in subsequent processes, a broad-spectrum composite demulsifier for saline drilling fluid systems was developed for the first time by utilizing a combination of strong electrolytes for demulsification, cations for flocculation breakdown, and adsorption-substitution mechanisms. This approach **reduces the amount of chemicals required and increases the proportion of liquid that can be filtered out after demulsification to over 20%.
Technological innovation 2: Multimetal catalytic oxidation technology. To address the prominent issues such as high water-soluble COD in fracturing return fluids, their difficulty in degradation, and the challenges associated with desalting these waste fluids, the technical team has innovatively developed multimetal catalytic oxidation technology. Air oxidation was used in place of traditional Fenton oxidation, and various transition metals were introduced to reduce the oxidation potential energy of organic pollutants, thereby enabling the degradation of waste liquids through air oxidation. This technology reduces the amount of chemical agents required, thereby improving the economic efficiency of wastewater treatment (the cost per ton of water treated is only 30% of that in the Fenton process).
Technological innovation 3: Chemical hardening removal + forced circulation evaporation crystallization technology. To address issues such as high salt content in pre-treatment wastewater, scaling during desalination, large fluctuations in water quality, stress on treatment systems, and high organic content that affects the efficiency of evaporation crystallization, the technical team developed the “chemical hardening removal + forced circulation evaporation crystallization” technology. By adding agents such as chelators to the crystallized salts, heavier salts can be produced as alternatives to KCl for use in drilling and well completion processes, resulting in significant energy savings.