Removal of scales in petroleum production tubing utilising high pressure atomisers

Enyi, GC; Nasr, GG; Nourian, A; El Kamkhi, MA; Burby, ML

Abstract

Scale is a mineral deposit usually formed on surfaces in contact with water. Scale deposition in petroleum
production wells can be attributed to mixing of incompatible waters, changes in thermodynamic, kinetic and
hydrodynamic conditions in oilfield operations.
Scale creates serious problems in producing, injection and waste disposal wells. It may restrict and completely plug off production in the formation, tubing or in flow lines. Scale prevention using chemical and mechanical methods are limited in application and depend on the type of well completion method used. This investigation proposes a new technique to address the problem and lay the foundations for a methodology for descaling in-situ production in oil and gas wells. The technique uses flat fan atomiser to produce high water pressure of
6 MPa, flow rate of 23 l/min and high impact force of 0.657 MPa which are used to dislodge scales build-up
along the production tubing. Simulated laboratory scale removal rig was designed and built to demonstrate the
effects of using overlapping flat fan spray atomisers to remove scales that were formed in oil and gas production
tubing. This non-destructive method provides significant advantages over current scale removal methods that
involve the use of chemicals or other harmful substances which are impediments to the environment and can also
affect the integrity of the pipe.
Three scale samples from oil and gas wells from North Africa and one laboratory prepared candle wax scale
were tested using single flat fan atomiser and a combination of two and three high pressure and high impact
force atomisers. The Volume of Scale Removed (VSR) was measured experimentally using a combination of
atomisers, at different spray angles, downstream distances, and water supply pressures and spraying times. The
maximum quantity of scale removed using the soft candle wax was found to be 53 cm3
at spray cone angle of 30
degree at 75 mm downstream distance from the atomisers exit. Moreover, the volume of scale removed from
other three samples was found to be 11.688 cm3
for the soft gas scale, 13.750 cm3
for the oil wax scale and approximately 0.989 cm3 for hard scale sample at 75 mm downstream distance.

Citation

Enyi, G., Nasr, G., Nourian, A., El Kamkhi, M., & Burby, M. Removal of scales in petroleum production tubing utilising high pressure atomisers. Presented at ICLASS 2012, 12th Triennial International Conference on Liquid Atomization and Spray Systems, Heidelberg, Germany

• Presentation Conference Type: Other
• Conference Name: ICLASS 2012, 12th Triennial International Conference on Liquid Atomization and Spray Systems
• Conference Location: Heidelberg, Germany
• End Date: Sep 6, 2012
• Publication Date: Sep 3, 2012
• Deposit Date: Feb 10, 2021
• Publicly Available Date: Feb 10, 2021
• Publisher URL: http://www.ilasseurope.org/ICLASS/iclass2012_Heidelberg/Contributions/Paper-pdfs/Contribution1144_b.pdf
• Related Public URLs: https://ilasseurope.org/events/12th-iclass-conference/
• Additional Information: Event Type : Conference