Lignosulfonates are mainly used as drilling fluid treatment agents, surfactants for tertiary oil recovery, and profile control and plugging agents in oilfield operations. Their core functions focus on improving the rheological properties of drilling fluids, increasing crude oil recovery rates, and optimizing downhole plugging effects.

1、 Drilling process: as a drilling fluid treatment agent
Lignosulfonate mainly plays a role in reducing viscosity, dispersing, and stabilizing mud properties during drilling, and is a key additive in water-based drilling fluid systems.
Viscosity reduction and dilution effect
By adsorbing onto the surface of clay particles, the flocculent structure is broken down, reducing the structural viscosity and shear force of drilling fluid, and improving its fluidity.
Specially suitable for freshwater, seawater, and saturated saltwater drilling fluid systems, it can maintain good dilution efficiency even in high salt and high temperature environments.
Strong temperature and salt resistance
Modified or chromium free lignosulfonates can withstand high temperatures above 180 ℃ and are suitable for deep, ultra deep, and offshore deviated well operations.
Has excellent resistance to calcium and magnesium, prevents salt precipitation failure, and ensures drilling safety in complex formations such as gypsum layers and saltwater layers.
Environmental upgrade trend
Traditional iron chromium lignosulfonates (FCLS) pose environmental risks due to their chromium content and are now being replaced by chromium free lignosulfonates. The latter can control chromium residue below 0.1ppm, which is practically non-toxic and has a high biodegradation rate.
In practical applications, it is often compounded with sulfonated tannins (SMT), sulfonated tannin extract (SMK), etc. to construct a high-temperature resistant composite treatment agent system.
2、 Oil extraction process: used for tertiary oil recovery (EOR)
Lignosulfonates and their modified products can serve as inexpensive and efficient alternatives to surfactants during the tertiary oil recovery stage to enhance oil recovery efficiency.
Reduce interfacial tension
Modified lignosulfonates (such as alkoxylation and sulfomethylation products) can form ultra-low oil-water interfacial tension with crude oil, promoting residual oil mobilization.
After compounding, the interfacial tension can be reduced by an order of magnitude, significantly improving oil displacement efficiency.
As a 'sacrificial agent' to reduce adsorption losses
In polymer/surfactant composite flooding, lignosulfonate preferentially adsorbs on the rock surface, protecting the main flooding agent and reducing the loss of expensive surfactants, with a reduction of over 60%.
Significant cost advantage
Compared to petroleum sulfonates, lignosulfonates are derived from papermaking wastewater, with renewable raw materials and low costs, which is in line with the direction of green oilfield development.
3、 Underground operation: used as a profile control and water plugging agent
Lignosulfonate can also be used for profile control in heterogeneous formations and water plugging operations in high water content wells, achieving increased oil production and precipitation.
High strength plugging agent formula
A high-strength plugging agent LT can be prepared by mixing lignosulfonate with sulfonated tannin extract, with a curing time of 2-25 hours and a compressive strength of 1.2 MPa. It is suitable for oil well environments at 40-50 ℃.
Gel profile control agent
Crosslinking with metal ions to form a gel with good thermal stability, improve the water injection profile, and improve the production degree of low-permeability layers, which has been successfully applied in Henan Oilfield.
Graft copolymer used for sealing
After graft copolymerization of wheat straw alkali lignin and acrylamide, the water solubility is improved, and it can be used as a selective water blocking agent or profile control agent, with both environmental protection and high efficiency characteristics.