Changes

Liquid that enters the wellbore at the bottom of the hole can only flow to the surface if the difference in pressure between the bottom and the top of the well is greater than the hydrostatic pressure of the fluid column, plus any friction that occurs as a result of flow up the tubing. If the pressure is not sufficient, the fluid will remain static in the wellbore. This is referred to as ''liquid loading''. If gas is primarily being produced, water flowing from the formation, or condensed within the tubing, can also accumulate in the wellbore if the gas is not flowing at sufficient velocity to lift the water from the well. Accumulation of this static fluid column can impose an additional backpressure on the formation that can significantly reduce the productivity of the well or can actually “kill” the well so that it does not flow at all.

Liquid that enters the wellbore at the bottom of the hole can only flow to the surface if the difference in pressure between the bottom and the top of the well is greater than the hydrostatic pressure of the fluid column, plus any friction that occurs as a result of flow up the tubing. If the pressure is not sufficient, the fluid will remain static in the wellbore. This is referred to as ''liquid loading''. If gas is primarily being produced, water flowing from the formation, or condensed within the tubing, can also accumulate in the wellbore if the gas is not flowing at sufficient velocity to lift the water from the well. Accumulation of this static fluid column can impose an additional backpressure on the formation that can significantly reduce the productivity of the well or can actually “kill” the well so that it does not flow at all.

When liquid loading occurs, it may be necessary to change the wellbore configuration or to install [[artificial lift]] equipment. For example, the size of the tubing affects the velocity of the fluid flowing up the well. If smaller tubing is used, the velocity of the fluid will be greater because of the smaller cross-sectional area. From a study of over 100 flowing gas wells, Turner et al.<ref name=pt09r24>Turner, R. G., Hubbard, M. G., Pukler, A. E., 1969, Analysis and prediction of minimum flow rate for the continuous removal of liquids from gas wells: Journal of Petroleum Technology, Nov., p. 1475–1482.</ref> developed a useful correlation to determine the minimum flow rate (and thus, velocity) required to lift liquids continuously from a gas well. Turner's correlation can be used to determine the size tubing required to remove water continuously from a well that is flowing at a specific rate.

When liquid loading occurs, it may be necessary to change the wellbore configuration or to install [[artificial lift]] equipment. For example, the size of the tubing affects the velocity of the fluid flowing up the well. If smaller tubing is used, the velocity of the fluid will be greater because of the smaller cross-sectional area. From a study of over 100 flowing gas wells, Turner et al.<ref name=pt09r24>Turner, R. G., M. G. Hubbard, A. E. Pukler, 1969, Analysis and prediction of minimum flow rate for the continuous removal of liquids from gas wells: Journal of Petroleum Technology, Nov., p. 1475–1482.</ref> developed a useful correlation to determine the minimum flow rate (and thus, velocity) required to lift liquids continuously from a gas well. Turner's correlation can be used to determine the size tubing required to remove water continuously from a well that is flowing at a specific rate.

In oil or gas wells that make large volumes of water or condensate, it may be necessary to install artificial lift equipment to pump the liquids to the surface. Most common methods of artificial lift include rod pumps, submersible pumps, and gas lift valves (see [[Artificial lift]]).

In oil or gas wells that make large volumes of water or condensate, it may be necessary to install artificial lift equipment to pump the liquids to the surface. Most common methods of artificial lift include rod pumps, submersible pumps, and gas lift valves (see [[Artificial lift]]).