Technology Update: Nanochemistry Drives New Method for Removal and Control of Wax
- Dauren Tukenov (Diversitech)
- Document ID
- Society of Petroleum Engineers
- Journal of Petroleum Technology
- Publication Date
- December 2014
- Document Type
- Journal Paper
- 30 - 33
- 2014. Copyright is retained by the author. This document is distributed by SPE with the permission of the author. Contact the author for permission to use material from this document.
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Paraffin wax precipitation and deposition is one of the pervasive nuisances in oil industry operations worldwide, with wax deposits creating problems from the wellhead to the refinery.
Up to 85% of the world’s oil is adversely affected by paraffin wax precipitating out and solidifying at the wellbore, in tubing, perforations, pump strings, and rods, and throughout the transfer system of flowlines and pipelines (Figs. 1a, 1b, and 1c). Precipitation and deposition causes equipment failures, bottlenecks upstream and downstream, and loss of production, transport capacity, and storage.
Because of paraffin wax deposition, thousands of wells are shut in, numerous pipelines blocked, transport vessels taken out of service, tanks locked in, and refinery equipment shut down at any given time globally, all resulting in loss of revenue.
Common remedies such as the application of hot oil or hot water, mechanical scraping, and solvent cleaning can be cumbersome, costly, and hazardous. They also are effective only for short periods and soon need reapplications.
Paralax, a novel chemical treatment that controls wax precipitation, was developed by a small United States-based engineering firm that has been acquired by Diversitech Holdings. The treatment does not fit conventional wax-control chemical definitions. More than a dispersant, solvent, or inhibitor, the chemical works when mixed and activated with crude oil by a proprietary nanochemical mechanism and attacks wax differently.
Flushing wax with activated crude oil removes the wax by layers and creates a waxophobic (wax repelling) condition for an extended period. The chemistry is also environmentally friendly, being nontoxic and nonvolatile, and the activator is safe to handle. Spills can be washed down and no special handling requirements are needed.
The advantages of activated crude oil treatment over other dewaxing methods are
- Significantly less labor for wax control, freeing personnel for other important tasks
- Significantly less frequency of treatment
- “Smart chemistry” that works by itself for 2 to 3 months after treatment when accompanied by proper maintenance to replenish waxophobic nanostructures
The benefits of the post-treatment waxophobic condition are
- Extension of wax-free production time of up to 3 months
- Lower load on pump, rod, and drive
- Fewer workovers caused by wax, such as pump hang-ups and broken rods
- Better well performance because of less wax in the tubing
Case Study: Subsea Pipeline
A dewaxing treatment was performed to clear a 28-mile, 8-in.-diameter subsea oil pipeline in the US Gulf of Mexico. Wax in the pipeline had gradually built up over 7 years and very aggressively in the final year. Various efforts had failed to prevent the buildup.
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