drilling fluid thickener Acid thickener AT350P Viscosity-Enhanced Acid System

High-Viscosity-Yield Acid Systems for High-Temperature Stimulation

Historically, both gelled and in-situ crosslinked acids have been used for fluid loss control during fracture acidizing and for diversion in matrix treatments in carbonate formations. Various synthetic polymers are used to gel the acid.

The reaction rate of hydrochloric acid and carbonate rock has a great influence on the acidification effect. Acid thickener AT350P can effectively slow the reaction rate of hydrochloric acid and carbonate rock. Acid thickener AT350P is a cationic, very high-molecular-weight polymer that increase the viscosity of hydrochloric acid as a gelling acid. As a dry powder type, AT350P is different from the traditional emulsion type drag reducing agent (containing a large amount of extra organic solvent and expensive surfactant), which has the advantages of transportation and storage, and is more economical and environmentally friendly.

In oilfield operations, acidizing is a common practice used to clean wellbore, dissolve carbonate deposits in the rock formation, and enhance well productivity. In this process, thickening agents play a crucial role. The function of thickening agents goes beyond simply increasing the viscosity of the liquid; they also affect the fluidity, suspension capability, and penetration depth of the acid solution.

Firstly, thickening agents control the fluidity of the acid solution. By thickening the solution, the acid becomes more viscous, slowing down its flow rate in the wellbore. This helps to extend the contact time and effectiveness of the acid, ensuring that it adequately reacts with the wellbore and rock surfaces to achieve the desired cleaning and dissolution effects.

Secondly, thickening agents enhance the suspension capability of the acid solution. During acidizing, solid particles and deposits may be carried by the acid solution, and the addition of thickening agents helps to keep these solid particles suspended, preventing them from settling in the wellbore. This helps to maintain the acid's action on the wellbore, ensuring that it can fully exert its cleaning and dissolution effects.

Additionally, thickening agents increase the penetration depth of the acid solution. Through thickening, the acid can better penetrate the rock formation's pores, enhancing the acid's etching effect. This means that the acid can more effectively clean the wellbore, dissolve carbonate deposits, and improve well productivity.

Therefore, the role of thickening agents in the acidizing process is crucial. It is not just about increasing the liquid's viscosity; more importantly, by controlling the fluidity, enhancing suspension capability, and increasing penetration depth, thickening agents enable the acid solution to more effectively achieve the objectives of cleaning the wellbore, dissolving deposits, and enhancing productivity. In oilfield operations, the selection and use of thickening agents are vital for the success of acidizing operations.

Refer to the safety data sheet (SDS) for handling, transport, environmental information, and first aid.

■ Creates a gelling acid system or a viscosity-enhanced acid system

■ Can be used as a friction reducer at lower concentration

■ No breaker is needed as gelling acid system because the product is self-degradable at high temperatures.

■ The product achieves maximum viscosity in 30 minutes and does not form “fish eyes”.

■ The maximum working temperature of the product can exceed 350F.