Cement dispersant (also known as drag reducer, water reducer or turbulence agent) is a material to improve the rheological properties of cement slurry. It is widely used in the cementing operation of oil and gas wells. In the future, it will develop in the direction of anti pollution, non-toxic, tasteless, non combustible, non explosive and non polluting the environment. In the process of oil and gas well cementing, cement dispersant (also known as drag reducer, water reducer or turbulence agent) is often used to improve the rheological properties of cement slurry and promote the improvement of cementing quality. The research in this field has been paid more and more attention by domestic cementing engineering circles. One time cement injection must have good displacement effect in order to achieve the purpose of sealing the formation. After long-term exploration and practice, people realize that in most cases, the method of turbulent cement injection is conducive to obtain high displacement efficiency.

 

Oil well cement dispersant can reduce the water cement ratio, improve the rheology and construction performance of cement slurry, and realize turbulent flow under low displacement and pump pressure. Therefore, the research and application of oil well cement dispersant has been continuously developed, and has become one of the most widely used and consumed oil well cement admixtures at home and abroad. At the same time, the advent of more new products has also brought direct economic and obvious social benefits to cementing operation and oil and gas field exploration and development.

 

Oil well cement dispersant can be divided into general type, saturated brine type and anti settlement type. According to its chemical composition, it can be divided into the following categories:

 

① Lignosulfonate and its derivatives;

 

② Naphthalene sulfonates;

 

③ Sulfonated ketal condensation polymer;

 

④ Water soluble melamine resin;

 

⑤ Sulfonated vinyl monomer polymers and their derivatives;

 

⑥ Citric acid;

 

⑦ Amps (2-acrylamide-2-methylpropanesulfonic acid) polymers;