PVA is a synthetic polymer that can dissolve in water and has numerous applications across different industries.
By substituting hydroxyl groups for acetate groups in polyvinyl acetate, PVA is produced. The chemical formula of PVA is [CH2CH(OH)]n, with n indicating the degree of polymerization.
Oil and gas are among the industries that use PVA extensively. As one of the most versatile specialty chemicals, it has been used to boost oil and gas extraction, processing efficiency, and performance.
This article delves into the applications of PVA in this sector. So, read on to learn more about this crucial chemical’s use in today’s oil and gas.
1. PVA In Drilling Fluids
One application of PVA is in drilling fluids, which act as a stabilizing agent in water-based muds (WBM).
PVA can enhance the performance of WBM by managing the viscosity and rheological properties of the mud. That prevents excessive fluid loss into the formation, promoting wellbore stability.
By forming a thin and flexible filter cake on the wellbore wall, PVA can reduce the invasion of drilling fluid into the formation and minimize damage. It can also swell in water and create a gel- like structure, increasing the viscosity and gel strength of the mud. That helps to suspend drill cuttings, transport them to the surface, and maintain hole cleaning and stability.
Furthermore, PVA can modify the mud’s rheological properties, including yield point and plastic viscosity. It affects the flow behavior and pumpability of the mud.
PVA is also compatible with most WBM additives, such as bentonite, starch, xanthan gum, and lignosulfonate. It even improves the thermal stability of WBM, allowing it to withstand temperatures up to 150°C without significant degradation.
Above all, being biodegradable and eco-friendly makes PVA suitable for offshore and environmentally sensitive areas. It’s a versatile polymer that can enhance WBM performance in various drilling conditions.
2. PVA In Fracturing Fluids.
PVA finds another of its applications in fracturing fluids.
Fracturing fluids generate and extend fractures in the rock formation, which allows oil or gas to flow effortlessly to the wellbore.
PVA functions as a thickener in fracturing fluids, increasing the viscosity and decreasing the friction of the liquid. It enhances its proppant-carrying ability, allowing more solid particles to be suspended and transported into the fractures to maintain their openness.
PVA also aids in regulating the viscosity of the fracturing fluid, as it can be easily degraded by enzymes or heat once the fracturing process is completed. It helps in the recovery and cleanup of the liquid.
Furthermore, PVA inhibits the formation of emulsions and fluid loss, which can reduce the effectiveness and increase the environmental impact of fracturing. It’s a biodegradable, non-toxic polymer that can replace synthetic polymers.
3. PVA In Enhanced Oil Recovery (EOR)
The oil and gas industry also applies PVA in enhanced oil recovery (EOR).
EOR is a process that enhances oil extraction by injecting various substances into a well. PVA can act as its surfactant, reducing the surface tension between liquids such as oil and water.
PVA can create stable emulsions by reducing the interfacial tension between fluids. These emulsions can improve the mobility and efficiency of the injected fluid, making it easier to extract trapped oil. PVA can also alter the wettability of the rock surface, making it more water-wet and less oil-wet. It makes the oil recovery process much more manageable.
Moreover, PVA is a synthetic polymer with good resistance to salinity and chemicals, high solubility in water, high viscosity, and high thermal stability. These properties make it suitable for EOR applications in various reservoir conditions.
Additionally, it can be mixed with other additives. Examples include sodium hydroxide (NaOH) or ethanol. This mixing can help improve PVA’s compatibility with heavy oil.
4. PVA As A Corrosion Inhibitor
Another application of PVA in the oil and gas industries is as a corrosion inhibitor.
Corrosion is a grave issue that can affect the safety and performance of equipment and pipelines in oil and gas production and transportation. It can result in environmental harm, explosions, failures, and leaks.
PVA can prevent metal surfaces from corrosion by creating a shielding layer that stops contact between the metal and corrosive mediums like saline or acidic solutions. It has a strong affinity for metal ions and can form robust bonds.
PVA also has hydroxyl groups that can interact with water molecules and decrease their availability for corrosion reactions.
According to reports, PVA has an inhibition efficiency of 50-70% based on the metal-acid system. Additionally, it can be combined with amino acids. The ones used include leucine, histidine, threonine, and cysteine. This combination can improve the inhibition efficiency to over 92% in 1M HCl.
Understanding Its Value
Overall, using PVA in the oil and gas industry is a significant technological breakthrough. As advances continue, specialty chemicals such as this will undoubtedly play a more significant role in solving industry challenges and promoting innovation.
