Consequently, a low volume of liquid is present in the tubing or production conduit, resulting in a pressure drop caused by gravity acting on the flowing fluids.
Possible solutions to this problem include the installation of a velocity string, a capillary string injecting foamers (often with corrosive effects on surface wellhead seals), or a pump to continuously or intermittently pump the water to the surface to remove the hydrostatic barrier that the water creates.
Improved electrical pumps coming onto the market may enhance the effectiveness of the technology.
More recently, downhole compressors are being used to increase velocity of gas flow, which in turn accelerates liquid unloading.
In this case, the reservoir pressure drops to such a low level that it cannot lift the weight of the oil/water column to the surface.