How DWAX Works
Paraffin, bitumen and asphaltene are heavy organics contained in crude oil. These components are the primary cause of oil flow restrictions or blockages in producing oil wells. Paraffin deposition occurs due to the lowering of crude oil temperatures, changes in pressure, and other factors resulting in the formation of crystalline solids (Afanas’ev, et al, 1993). These heavy solids stick to the walls of all equipment coming in contact with crude oil including; tubulars, flow lines, pumps and tanks. As the paraffin builds up, arterial blockage occurs resulting in increased friction, reduced oil flow and potentially complete restriction. The increased friction from this build-up can also cause equipment breakdown and failure. DWAX paraffin and asphaltene removal program greatly improves performance and reduces costs.
Conventional practices are costly and time consuming including; scraping (where production must cease and the cap is removed from the well), chemical programs (often requiring extensive safety procedures, shut down and flushing after use) and hot oiling with limited success. The problem with most methods is not only the cost, but rather that they only soften and move the paraffin further down the line where it precipitates out elsewhere. The DWAX solution removes paraffin and asphaltene from your wells by permanently encapsulating them in a liquid state that cannot cross-link back into a solid.
DWAX solvent is a proprietary mixture of bio-based detergents, surfactants, and organic solvents specifically formulated for the purpose of breaking down these heavy deposits while allowing pump operations to continue. DWAX’s solvent is hydro-carbon based and is both oil soluble and water dispersible. A DWAX service liquefies paraffin and other heavy deposits to the point where they flow freely with the oil stream and are captured for sale.
The following experiment demonstrates paraffin removal using DWAX solvent.
Properties of Paraffin
- Paraffin was was first identified by Carl Reichenbach in 1830. It refers to alkane hydrocarbons with the formula CnH2n+2. The solid forms of paraffin (paraffin wax), are from the heaviest molecules (C20H42 to C40H82).
- Alternate names: petroleum wax, hydrocarbon wax
- Melting point: 50°C-57°C
- Flash point: 199°C
- Specific gravity: 0.72
- Density: 0.9 g/cm3
Our experiment starts with a sample of paraffin taken directly from an Alberta oil well. This sample is typical of paraffin deposits that build-up in oil production equipment causing flow restrictions and equipment failure.
DWAX’s solution is now added to the container where it immediately starts to dissolve the Paraffin.
In the field, the product is heated and injected into the annulus where it would reach the restriction and flow up the tubing. The amount of solvent used would depend on the depth of the well and the extent of the build-up. For this experiment, enough solvent was added to make it quite obvious that the Paraffin has been completely liquified.
At this point the container is rocked back and forth several times until the paraffin has been completely dissolved into the solvent.
In the field this is done by operating the pump to agitate the solvent.
After heating the mixture to 70° for about 5 minutes, the solution becomes transparent indicating that the paraffin has been completely broken down and liquefied.
In the field, the solution is heated before being injected into the well utilizing our specialized equipment so we may control the tempurature at a range of 60C to 120C. This allows us to be able to be cool enough to work in fiberglass flow lines, and also adjustbale to be hot enough to adress the toughest of restrictions.
As seen in the last photo, the paraffin is molecularly re-structured, resulting in an oil soluble and water dispersible product that mixes in with the oil stream and will not precipitate out in the flow line.
- Katz, D. H. and Beu, K. E., “Nature of asphaltic substances,” Ind. Eng. Chem. 37 (1945), pages 195-200.
- Mansoori, G. A., “Remediation of heavy organic deposits in petroleum production,” presented at IBC’s 1998 Controlling Hydrates, Waxes and Asphaltenes Conference, New Orleans, Louisiana.
- Thomas J. Glover, “POCKET REF,” Second Edition (1996)