ACOUSTIC WELL STIMULATION (AWS)
AWS was specifically designed to enhance oil flow from producing wells utilizing primarily three basic methods, (i) freeing the perforation channels from accumulated debris, (ii) elimination of the “skin effect” and (iii) significantly reducing the viscosity of the of oil.
HOW DOES AWS WORK
A powerful Downhole Acoustic Emitter Tool (DUET) is placed adjacent to the perforation zone producing ultrasonic pulses which vibrate the formation fluid thereby dislodging any debris that is blocking the perforation channels and the transmission of kinetic energy into the formation fluid thus reducing the viscosity of the fluid.
AWS EQUIPMENT & TOOLS
AWS is conducted by inserting into the production tubing a DUET adjacent to the perforation interval connected via a geophysical cable to a surface ultrasound generator, therefore the AWS equipment consist of (i) Surface Ultrasound Generator, (ii) Downhole Ultrasonic Emitter Tool (DUET), and (iii) Geophysical Cable capable to transmit at least 10 KW
AWS METHODS & APPLICATIONS
There are 2 main types of AWS, Short Term Stimulation and (STS) and Long Term Stimulation (LTS).
- STS is recommended for wells with low viscosity oil to clean up the perforation channels of accumulated debris and is conducted periodically depending on downhole conditions.
- LTS is recommended for oil with high viscosity and is performed by permanently fixing the DUET alongside the perforation interval and conducting frequent AWS to significantly reduce the viscosity, stimulation occurs every 2-4 days depending on downhole conditions and is agreed with the client after evaluation of the logging data.
ADVANTAGES OF AWS OVER OTHER EOR METHODS
- As AWS uses only physical means to stimulate production, no chemicals or reagents are involved thus eliminating any risks to the formation zone or the environment as a whole
- As AWS, both STS and LTS, don’t affect the well structure or integrity, AWS can be repeated multiple time with no adverse effect whatsoever
- The results of AWS can be readily observed immediately after re-logging the well and production increase measured after restarting the well and the pump rate increased
- AWS using the LTS method ensures almost continuous stimulation with no down-time