Hydraulic fracturing, commonly known as fracking, is a well stimulation technique in which a high-pressure fluid, typically water mixed with sand and chemicals is injected into a wellbore in order to create small fractures in rock formations. When the fluid pressure is removed from the well, small grains of hydraulic fracturing proppants remain in the well and hold open the small rock fractures to allow oil or gas held within the rock to migrate to the main well. The first experimental use of hydraulic fracturing was in 1947, and commercially successful applications of fracking followed shortly after. The oil and gas extraction technique is very common within the USA but is becoming increasingly common globally.
The method works when a fluid is injected into the wellbore, with the pressure above the fracture gradient of the rock which contains oil or gas. A fracturing fluid is used to carry proppant into the rock formation, the purpose of which is to stay there without damaging the formation or production of the well. A fracture fluid contains water-soluble gelling agents such as guar gum, functionalised guars, celluloses and functionalised celluloses which increase overall fluid viscosity and allow for more efficiently deliver the proppant into the formation for minimal polymer use.
The specific role of the cross linker is to increase the total fluid viscosity, allowing for greater levels of proppant to be carried by the fluid while doing so at much lower polymer levels. Typical fluid formulations contain less than 0.5% chemicals with almost all of the fluid made up of water and proppant. The most common cross linkers are based on borates and zirconates, however, both of these product types have both advantages and disadvantages to the user. Catalytic Technologies Ltd’s new products have solved a wide range of the historical disadvantages of zirconates and offer customers unique cross linking performance with unrivalled flexibility.
It is now common for water used in fracking fluids to be recycled which can lead to high levels of total dissolved solids. While this can be problematic for standard borates and zirconium cross-linkers, the new Catalytic Technologies Ltd products demonstrate high levels of performance, even at TDS up to 300,000 ppm.