Urengoy oil-gas condensate field is at the final development stage characterized by reservoir depletion and reservoir pressure decline.

To stabilize the production of raw hydrocarbons at Urengoy field it is stimulated by using hydraulic fracturing. Hydraulic fracturing is performed at gas, gas condensate and oil wells in Bolshoi Urengoy, where upon the completion of works it becomes necessary to ensure good bottom hole cleaning, i.e. to remove the proppant plug from the well bore. In accordance with the operating procedures adopted at Urengoy filed, the hydraulic fracturing is carried out predominantly by underflashing the proppant into the formation; in other words by leaving the proppant in the perforation interval and above it.

Bottom hole cleaning in oil wells located at the margins of the field – at socalled oil rims – present special difficulties. There is considerably less reservoir energy here than in the central areas where gas and gas-condensate wells are located. In such challenging geotechnical conditions the choice of the bottom hole cleaning technique and its efficient implementation greatly influence the outcome of the hydraulic fracturing. In addition to that, good flushing of the oil well can have an impact on timely (scheduled) or premature putting out of operation of the downhole equipment, and centrifugal pumps in particular.

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