CONDITIONS FOR THE ACCUMULATION OF WATER AND CONDENSATE AT THE BUTTONHOLE OF GAS AND GAS-CONDENSATE WELLS AND ITS IMPACT ON THE OPERATING REGIME

This paper identifies the conditions for the accumulation of water and condensate at the buttonhole of gas and gas-condensate wells and evaluates the effect of the resulting liquid column on the operating regime. In gas-condensate wells operating under depletion conditions, reservoir pressure gradually falls below the dew-point pressure. Under these conditions, two-phase flow develops in the well, leading to operational complications. The accumulation of liquid at the buttonhole creates resistance to flow, causing the well production rate to decline and eventually reach zero. Water entering the well together with condensate is generally not lifted to the surface but accumulates in the wellbore, forming a liquid column. Water loading of gas and gas-condensate wells reduces production rates, creates various operational difficulties in the wellbore, increases the volume of separated liquids, and provides favorable conditions for the formation of crystalline hydrates. Surface and downhole equipment are also subjected to corrosion and other adverse effects. An analysis of the causes of water loading in affected wells shows that wells may be watered by their own formation waters. In such cases, wells can be operated in a water-free production regime, enabling the selection of effective methods to control water loading. Methods for investigating well water loading are presented. One of these methods is the hydro chemical analysis of formation water composition, in which the chloride ion content is determined. For this purpose, water samples are taken from separators, and the chloride ion concentration, water salinity, and water volume are measured. The study demonstrates the possibility of lifting liquids using the energy of the gas in the well with the aid of surfactants, as well as through the application of new equipment and technologies. Keywords: gas-condensate wells, depletion regime, well water loading, settled water, water salinity, liquid column, surfactants, gas–liquid mixture, well production rate, stimulation method.