Chemical stimulation of gas condensate wells

Abstract

Gas wells are susceptible to sub-optimal performance due to accumulation of liquid in the near wellbore region of the producing well. This liquid may arise when the bottom hole flowing pressure drops below the dewpoint pressure of the fluid and a gas condensate bank (retrograde condensate) forms in the near wellbore region of the producing well. Alternatively, water may be present from many natural and man-made causes, ie, connate water, water from an aquifer, bottom water, crossflow from another zone, completion/fracturing fluids, etc. In a worst case scenario, both of these situations can occur and cause severe liquid blocking of the gas. In all instances, capillary forces trap some of this liquid in the pores resulting in a high liquid saturation and a reduction in the relative permeability of both the gas and the condensate, which is the root cause of the loss in production. Even for lean gas (1% liquid dropout) significant liquid condensate saturations can build up near the wells and can decrease production by a factor of two or three. Copyright 2007, International Petroleum Technology Conference.