Thread Content
Applications of humic acid products in oil fields: Due to the characteristics of its structure, humic acid is widely used in oil fields. Currently, humic acid-based products are primarily used in oil fields as drilling fluid additives, owing to the hydrophilicity, chelating ability, and adsorption/dispersing properties of their molecules. These products help to reduce filtration loss, viscosity, and collapse risks, and they also possess good resistance to salts and high temperatures. (1) Loss control agents: Most humic acid-based loss control agents are anionic sulfonated products obtained by reacting humic acid with aldehydes, phenols, polyacrylonitrile, and sulfonating agents, and they are suitable for various types of drilling fluid systems. Tan Daozhong developed the high-temperature resistant filter loss reducer SPNH using sulfonated chromium humate SMC, sulfonated phenolic resin SMP, and HPAN. This product possesses both viscosity-reducing properties as well as capabilities to prevent formation collapse and blockages, and it has achieved good results when applied in 35 wells in the North China Oilfield. Wang Pingquan obtained the improved fluid loss reducer G-SPNH by reacting lignite, waste acrylic fibers, phenol, formaldehyde, and sulfonating agents. This product exhibits significantly better fluid loss reduction and viscosity reduction properties under high-temperature (above 200°C) and high-salt (15% NaCl) conditions compared to similar sulfonated agents. Li Chaoxing synthesized the fluid loss reducer SDX through reactions involving humic acid, acrylic waste yarn, sulfonated phenolic resin, etc. The product was successfully applied in the Zhongyuan oil field, which features numerous faults and thick salt beds. **Sen et al. developed FD2-1 using Xundian lignite, formaldehyde, phenol, sodium polyacrylonitrile, and sodium sulfite as raw materials; the resulting product exhibits excellent temperature and salt resistance: under high-temperature (150°C) and high-salt (15%) conditions, its fluid loss reduction performance is superior to that of SPNH and the American product Resinex. Wang Xiaoshi and others synthesized RSTF through the graft copolymerization of two or more monomers with humic acid. Through internal evaluations as well as applications in over 30 wells in the Sichuan and Tarim oil fields, it demonstrated strong resistance to salt and calcium contamination, and was able to significantly reduce the high-temperature and high-pressure filtration loss of water-based drilling fluids under various conditions ； In recent years, cationic humic acid fluid loss reducers have also been developed and applied. Liu Yuqing et al. synthesized the anti-collapse and fluid loss control agent CHSP2 using sulfonated humic acid, phenol, formaldehyde, hydrolyzed acrylic waste yarn, and cationic acrylamide. Field applications have shown that this product exhibits good temperature and salt resistance, as well as effective fluid loss control properties; it also has strong inhibitory capabilities and anti-collapse effects. Liu Ying and others developed the cationic high-temperature resistance and filtration loss control agent CAP through reactions involving lignite, sodium hydrolyzed polyacrylonitrile, diethyl diallyl ammonium chloride, AMPS, urea, formaldehyde, etc. This product exhibits excellent resistance to high temperatures (200°C), salts (saturated conditions), and calcium (7000 mg/L) ； Oil-soluble humic acid fluid loss reducers have also been developed. The Ying-Qiong Basin in the western South China Sea is a gas field with great development potential, but it features harsh geological conditions, high abnormal pressures, well depths exceeding 5000 meters, and a predicted maximum bottom hole temperature of 220°C. In such cases, conventional fluid loss inhibitors are no longer sufficient; they will desorb and decompose at high temperatures, resulting in partial or complete loss of effectiveness. Gao Haiyang et al. modified humic acid through ammonolysis to develop the Xnt rol 2220 oil-based drilling fluid, and the product was compared with the American Versalt rol loss control agent. Table: Comparison of properties of diesel-based drilling fluids – Loss control agents, demulsification voltage / V, AV / mPa·s, PV / mPa·s, YP / mPa·s, FL / mL, FLHTHP / mL. Xntrol A-220: >2000, 106, 95, 6.2, 0, 12; Versaltrol: >2000, 123, 100, 21.6, 1.0, 56. Comparison conditions: 220°C, 3.45 MPa. As can be seen from the table, Xntrol 2220 is an effective loss control agent capable of withstanding high temperatures of 220°C; its filtration volume at these conditions is 12 mL, which is less than the 20 mL specified by the API RP 13B standard. Thus, its performance meets all API requirements. In addition, it possesses certain emulsification and dilution capabilities, enabling the drilling fluid system to have good rheological properties, and its effectiveness is far superior to that of the American Versaltrol loss control agent. (2) Shale inhibitors: Polymer-based drilling fluids exhibit good inhibition and shear-thinning properties, but they have poor wall-building ability and high filtration rates. Liu Zilong and others developed organosilicon humate salts, which are formed by the condensation of appropriately polymerized methylsilanol with humate salts under the catalysis of aluminum salts. These compounds possess both the high-temperature stability and inhibition properties of organosilicon treatment agents, as well as the viscosity-reducing and filtration-loss-reducing effects of humic acid-based treatment agents. Field application results show that these products have certain inhibition capabilities and can effectively improve the wall-forming properties of drilling fluids. Li Xiangshan modified humic acid using chlorosilanes to develop the HA-Si series of inhibitors, which possess excellent thermal stability and dispersion properties and can inhibit the swelling of shale and drill cuttings. He also developed the loss control agent SCUR through graft polymerization of active humic acid with carbamide derivatives; this agent, when combined with sulfonated asphalt, KAHM, NH4HPAN, and KHm, exhibits a strong ability to suppress the hydration and dispersion of shale, resulting in mud cakes that are thin, dense, and smooth, as well as low permeability. Yu Peizhi et al. synthesized the collapse and filtration control agent KH-931 by reacting humic acid with acrylamide, acrylonitrile, etc. It exhibits good performance in preventing collapse and controlling filtration, is non-fluorescent, and does not affect geological logging. Li Jianying and others developed the non-fluorescent water-based drilling fluid loss control agent MHP by reacting potassium nitrohumic acid with sulfonated phenolic resin. This agent possesses excellent resistance to high temperatures and salts, works well in combination with other treatment agents, and is suitable for exploration wells, deep wells, and wells in complex geological formations. Zhang Gaobo and others synthesized cationic lignite using cationic monomers and lignite in the presence of alkali and catalysts. This product exhibits excellent anti-collapsing properties, enabling it to effectively suppress the swelling and dispersion of shale and prevent further slurry formation by bentonite. (3) Viscosity reducers: Viscosity reducers are essential drilling fluid additives used during drilling, and they play a very important role in regulating the rheology of the drilling fluid. Chromium-containing viscosity reducers such as FCLS and SMC have been the most widely used types in oil fields for many years, but they cause severe environmental pollution. Li Xiangshan and others developed the chromium-free viscosity reducer GHm by replacing chromium with manganese. This product requires less usage than SMC, offers longer-lasting performance compared to FCLS, and features low production costs, good compatibility, strong inhibitory effects, as well as resistance to temperature and salts. Zhang Xijiu and others developed the SMCT chromium-free high-temperature viscosity reducer from modified lignite; its performance is equivalent to or superior to that of FCLS, it can meet the requirements of drilling in deep wells over 4000 meters, and it is easy to use with low production costs. Luo Yue and others synthesized binary, ternary, or quaternary series copolymers using humic acid and olefin monomers, which can be used as viscosity reducers, viscosity enhancers, and fluid loss inhibitors, respectively, and also possess a certain ability to prevent clay swelling. Su Changming and others developed the viscosity reducer XG1 using lignosulfonate, humic acid, chelating agents, and other reagents. This reducer achieves a dilution efficiency of over 95% for bentonite-based drilling fluids at high temperatures, and over 85% for high-density drilling fluids; it can also withstand temperatures above 180°C. Fan Hongfu developed the viscosity reducer HKSF using tannin, humic acid, chelating agents, and other reagents; its viscosity-reducing performance is superior to that of SMK and FCLS, while its resistance to salts and calcium is on par with that of FCLS. This post was last edited by majingkunmail on 2009-2-19 15:49.]