Application of Sodium Humate in Drilling Fluids

In drilling operations, drilling fluid plays a crucial role because there are many types of highly active functional groups in humic acid sodium,  such as methoxy, enol, amino, carbonyl, etc., which have good complexing ability, adsorption dispersion, and strong hydrophilicity, acidity, and surface activity. Sodium humate is used as a modification additive in drilling fluids used in petroleum drilling engineering.

The conventional application methods of sodium humate mainly include shale inhibitors, filter loss reducers, viscosity reducers, etc.

(1) Shale inhibitors. Polymer drilling fluid has good shear dilution and inhibition effects, but its filtration rate is relatively high and its wall building performance is relatively poor. The organic silicon formed by the condensation of sodium humate and polymerized appropriate methyl silanol under the catalytic action of aluminum salt has the functions of reducing filtration and viscosity of sodium humate treatment agents, as well as the inhibitory performance and high-temperature stability of organic silicon treatment agents, which can effectively improve their wall building properties; The inhibitor made from sodium humate modified with chlorosilane has good dispersion and stability, which can inhibit the expansion of drilling cuttings and shale; The composite system composed of SCUR, NH4HPAN, KAHM, KHM, and sulfonated asphalt, which is an anti sloughing fluid loss agent formed by grafting polymerization of derivatives of carbonamide and active humic acid sodium, has a strong inhibitory ability on the dispersed water splashes of shale, low permeability, and dense, smooth, and thin mud cake; KH2931, an anti collapse filter loss agent generated by the chemical reaction of acrylonitrile, acrylamide, and sodium humate, has no fluorescence and does not affect geological logging. The anti collapse filter loss effect is relatively good; Utilizing sulfonated phenolic resin with nitro groups

MHP, a non fluorescent water-based drilling fluid produced by the chemical reaction of sodium and potassium humate, has good compatibility with other treatment agents and has salt and temperature resistance, making it suitable for use in complex formation wells, deep wells, and exploration wells.

(2)Filter loss reducing agent. Sodium humic acid type filtration reducers are mostly sulfonated products of anions generated by the chemical reaction of aldehydes, polypropylene, sulfonation agents, and phenols with sodium humic acid. They are composed of water-soluble ions and can resist salt and high temperature, making them suitable for many drilling fluid systems. The high-temperature resistant fluid loss agent SPNH generated by using HPAN, sulfonated phenolic resin (SMP), and sulfonated sodium humate (SMC) has anti jamming, anti collapse, and viscosity reducing capabilities; Under high salt (15% NaCl) and high temperature (>200 ℃) conditions, an improved type of fluid loss reducer - G2SPNH, which is generated through the reaction of sulfonation agents, formaldehyde, phenol, waste acrylic fibers, and lignite, has better viscosity and fluid loss reduction effects than similar sulfonation treatment agents; The use of sulfonated phenolic resin, acrylic fiber waste, sodium humate and other chemical reactions to generate a filter loss agent - SDX - has also been successfully applied.

(3) Viscosity reducer. It is an indispensable drilling fluid treatment agent in drilling operations and plays a crucial role in regulating the rheological properties of the drilling fluid. In oil fields, the most commonly used varieties include SMC and chromium containing viscosity reducers (FCLS). However, they also cause serious environmental pollution. Chromium free viscosity reducers (GHMs) have been manufactured using manganese instead of chromium, and their dosage is less than SMC. The effect is also more durable than FCLS, with good compatibility, salt resistance, temperature resistance, strong inhibition, and low production costs; The high-temperature resistant and chromium free viscosity reducing agent (SMCT) generated by modifying lignite has better performance than FCLS, and can be used for drilling operations in deep wells greater than 4km, with low production costs and convenient use. The binary series of copolymers generated by the reaction between olefinic monomers and humic acids can be used as viscosity reducers, ternary copolymers can be used as viscosity enhancers, quaternary copolymers can be used as filter loss reducers, and have anti clay swelling effects; Using complexing agents, sodium humate, lignosulfonate, and other reagents to form a viscosity reducer - XG21 dilutes bentonite drilling fluid with an efficiency of over 95% under high temperature conditions, dilutes high-density drilling fluid with an efficiency of over 85%, and can withstand high temperatures exceeding 180 ℃; The viscosity reducing agent HKSF, generated by complexing agents, sodium humate, tannin extract, and other reagents, has a viscosity reducing effect that exceeds that of FCLS and SMK, and its ability to resist calcium and salt is also equivalent to that of FCLS.

The most common new application methods of sodium humate in drilling fluids include fungicides, corrosion inhibitors, and scale inhibitors. Sodium humate has strong antibacterial ability. After modification with quaternary amine, its algal killing and sterilization effects can be better exerted, and the metabolism of microorganisms can be disrupted, making them unable to metabolize normally. This can effectively inhibit harmful microorganisms in drilling. In addition, sodium humate can also regulate the acidity and alkalinity of drilling fluid, have a scale inhibiting effect, and prevent acidic gases from corroding drilling equipment. Therefore, it can be used as a corrosion inhibitor and scale inhibitor.

The application of oil drilling fluid containing sodium humate inhibits the dispersion, hydration and swelling properties of mud shale, reduces the water loss of drilling fluid, and improves the potential of drilling fluid, so it can very effectively strengthen the ability of drilling fluid to reduce filtration loss and dilution effect. Under the condition that the filter loss reduction and dilution of drilling fluid are effectively strengthened, the suspended charge of clay can be effectively enhanced, the hydration film can be thickened, and the dynamic electrical properties can be effectively increased, which is conducive to the improvement of physical properties of drilling fluid, such as calcium resistance, salt resistance and high temperature resistance, and can meet the requirements of anti-collapse ability, lubrication ability and sand carrying ability of drilling fluid.

It can meet the requirements of anti-collapse ability, lubrication ability and sand-carrying ability of drilling fluid. When preparing sodium humate, tap water is added to the container, then hydrochloric acid is slowly added to it, and the mixture of hydrochloric acid and tap water is mixed well with sufficient stirring. The product is then washed repeatedly, 3~5 times, to ensure that the pH of filtrate is more than 4. Sodium humic acid is prepared, organic amine is mixed with it evenly, and the reaction is charged with inert gas under high temperature conditions, and finally the product is finely ground and sieved, and after the above operation, humic After the above operation, humic acid is used as a filter loss reduction agent.