Polydadmac (polydiallyldimethylammonium chloride) has several applications in the oil field industry, mainly due to its cationic nature and ability to interact with various substances present in oilfield waters. Here are some of its uses:

1. Water Treatment: 

In oil extraction processes like Enhanced Oil Recovery (EOR), polydadmac is used as a water-soluble polymer for waterflooding operations. It can act as a scale inhibitor, preventing mineral deposits from forming on pipes or production equipment, which can obstruct flow and reduce efficiency.

2. Oil/Water Separation: 

Polydadmac can improve the separation of oil and water mixtures that occur naturally during oil production or in produced water treatment. Its high charge density helps in coagulating and flocculating emulsified oils, making it easier to separate them from the water phase.

3. Drilling Fluids: 

As an additive to drilling fluids, polydadmac can enhance the fluid's viscosity and filtration properties, thereby improving wellbore stability and reducing fluid loss into the formation.

4. Corrosion Control: 

By neutralizing acidic components in produced water, polydadmac can help control corrosion in pipelines and other metal structures within the oilfield.

5. Clay Stabilization: 

In oil reservoirs, clay swelling can cause severe damage to the formation's permeability, affecting oil recovery. Polydadmac can be used to stabilize clays by adsorbing onto their surfaces, limiting swelling and migration.

6. Waste Management:

 It aids in sludge dewatering processes, making it easier to handle and dispose of the waste generated during oilfield operations.

7. Biocides: 

Some forms of polydadmac exhibit antimicrobial properties, which may find application in controlling bacterial growth in oilfield systems, reducing biofilm formation, and extending the life of the equipment.

In each application, the dosage and specific formulation of polydadmac are carefully controlled to achieve optimal results while minimizing any potential negative impacts on the environment or operational efficiency.