Recently, in the laboratory of the Oilfield Chemistry Research Institute at the Drilling Engineering Technology Research Institute of Zhongyuan Petroleum Engineering Company, drilling fluid technology expert Su Xuexia is leading technicians to test the filtration reduction, temperature resistance, pressure resistance, and other properties of the newly developed multifunctional long-lasting polymer treatment agent. Holding a bag of off-white small granular samples, Su Xuexia introduced: "By adding a certain proportion of the new treatment agent to the drilling fluid, the drilling fluid can maintain stable fluidity even at a high temperature of 220 degrees Celsius."

After two years of effort, the institute's independently developed multifunctional long-lasting polymer treatment agent based on the "pendant group" concept has achieved breakthrough progress. Experimental data show that this treatment agent performs excellently under extreme conditions such as high temperature, high salinity, and high density. It not only significantly reduces the filtration loss of drilling fluid but also greatly enhances the stability and anti-pollution capability of the drilling fluid, providing strong technical support for the efficient development of deep wells, ultra-deep wells, and shale gas horizontal wells. This achievement won the first prize for outstanding papers at the 21st National Drilling Fluid and Completion Fluid Technology Exchange Seminar.

Replacing Traditional Structure with "Pendant Groups"

The working principle of traditional drilling fluid treatment agents is similar to "detergent removing oil stains"—through charged molecules adsorbing drilling cuttings particles, wrapping them in a layer of "slippery outer coat," making it easier for the mud pump to flush the cuttings out of the wellbore. However, as oil and gas exploration and development gradually advance toward deep wells, ultra-deep wells, and unconventional oil and gas fields, geological conditions become more complex. Traditional drilling fluid treatment agents are prone to issues such as molecular weight reduction and group variation under high-temperature and high-shear conditions, leading to functional failure and high maintenance costs.

In addition, traditional treatment agents have excessively high viscosity at low temperatures and excessively low viscosity at high temperatures, making it difficult to balance rheology and filtration loss control, severely restricting drilling efficiency.

To address these issues, Wang Zhonghua, former senior expert of Sinopec Group, broke through the traditional mechanism of treatment agents and proposed the "pendant group" concept. In molecular design, "pendant groups" were introduced to transform the mechanism of traditional treatment agents relying on adsorption groups and hydration groups into one based on pendant groups and hydration groups.

Researchers used "pendant groups" to replace the traditional structure, akin to equipping molecules with flexible "robotic arms": when the drilling fluid flows, these "arms" retract to reduce resistance; when the drilling fluid is static, they extend, holding hands to form a stable network to support the cuttings. This ensures the fluidity of the drilling fluid during operations and maintains its stability during shutdowns.

"This treatment agent can solve the core problem of traditional adsorption groups failing due to group desorption at high temperatures," said Wang Zhonghua.

Laboratory data show that the new treatment agent can withstand 220 degrees Celsius high temperature and remains stable after immersion in saturated brine. More notably, it integrates multiple functions such as increasing viscosity, enhancing shear, reducing medium-pressure filtration loss, and high-temperature high-pressure filtration loss. "Problems that used to require a dozen treatment agents can now be solved with just two or three," Su Xuexia vividly analogized, "It's like in the past, going out required carrying a wallet, key case, and card case; now one smartphone solves everything." This new treatment agent not only greatly reduces the types of drilling fluid treatment agents needed but also decreases the total dosage by more than 30%. Su Xuexia introduced that the cost of this additive is similar to common drilling fluid polymer stabilizers, yet its performance is superior to materials already good at high-temperature resistance; its ability to control drilling fluid filtration loss under high-temperature and high-pressure conditions is better than traditional materials, truly achieving the goal of "low cost, multifunctional."

In terms of production process, the research team adopted "inverse micro-suspension polymerization" technology. This process is like making the "popping boba" in pearl milk tea, allowing raw materials to react in tiny droplets, with no wastewater or waste gas emissions throughout, and no need for drying and grinding, avoiding dust pollution. The finished product is porous spherical particles that dissolve much faster than traditional powders, like effervescent tablets that dissolve instantly in water.

Currently, researchers have applied this additive in simulations of nearly 300 wells across 75 series of conditions in the laboratory, with experimental results surpassing design indicators.

Wang Zhonghua stated that although the research and development has achieved significant results, researchers are still deeply studying the mechanism of polymer treatment agents. Next, the team will further optimize the synthesis process, accelerate the transformation of scientific research achievements, and promote wider application of this additive.