CT technologies are widely implemented by Schlumberger in Russia for cleanouts of oil and gas wells as well as for production stimulation, logging and also drilling the horizontal wells. CT operations in Astrakhan field are an example of successful experience of CT intervention in highly sour high pressure/high temperature environment.

Astrakhan gas condensate field is extremely harsh in terms of highly corrosive conditions, due to H2S concentration of up to 26% vol., bottomhole temperature of 110 C and formation pressure as high as 600 bars. All this has a significant corrosive effect on downhole equipment during well production and workover.

The field has been in production since the middle 80’s and there is a tailpipe 100 to 200 meters long installed as a part of completion. The tailpipe (tubing) is overlapping the production zone for 50–100 meters and there-fore highly susceptible to corrosion. That corrosion of tubing metal can result in the coiled tubing becoming stuck during CT operations. During well interventions with CT, the fluid is circulated to the surface with flaring of gas phase after separation. It is not always possible because of towns and villages located close to the field.

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