Increasing fluid production by properly venting formation gas in insert chamber installations

摘要

Accumulation chambers are generally recommended for wells with low bottom-hole pressure and high productivity index. Insert chamber is one type of accumulation chamber that is used when casing conditions do not allow the installation of double packer chambers or when lowering the point of gas injection bellow the top of teh perforations will increase the liquid production. In normal intermittent gas lift operations the formation gas is constantly being vented to the well head and no gas accmulation can occur. For insert chamber installations, formation gas has to travel downwared first through the annular space between the performation and the outside pipe of the chamber. A complicated two-phase flow process takes place in this annulus with formation gas trying to move upward and accumulate at the top, while the liquid is moving downward carrying some formation gas with it. To avoid the accumulation of formation gas in the outer annular space that can block the liquid flow from the reservoir, it is important to provide a way of venting this free gas to the surface. Insert chambers are highly recommended in some low static pressure reservoirs located in the northern part of Lake Maracaibo where the perforated intervals are, in many cases, as long as 25