Recent experimental studies on intermittent gas lift havernshown that the lift efficiency of this method decreasesrndrastically as the viscosity of the fluid to be lifted increases.rnAs the viscosity increases more gas is needed to keep thernfallback losses at a minimum. One way to get around thisrnproblem and eliminate fallback losses is to implement the usernof Gas Chamber Pumps (GCP’s).rnGCP’s are highly appropriate for shallow wells producingrnheavy oil in places where high-pressure injection gas isrnavailable. That is the case of some wells in Lake Maracaibornand in some places in the eastern oil fields in Venezuela thatrnare currently producing oil of 14 to 23° API from reservoirsrnlocated at depths between 2000 and 3500 ft.rnA variety of different GCP configurations can be found inrnthe literature, from highly complex and compact units tornsimple types of completion that can be implemented withrnminor changes of current gas lift completions. The advent ofrnsimple and highly reliable programmable surface controllers isrnmaking it possible to simplify subsurface completion. Thernsimplicity of these new completions implies a new andrneconomical way of implementing GCP’s where they arernappropriate.rnA description of how different GCP’s work and the mostrnpopular configurations are given in this paper. It is alsornexplained in detail a new and simple engineering procedure tornestimate the liquid production and gas consumption of a wellrnproducing with a GCP. This procedure takes into account therninflow capability of the well and couples this capability withrnthe pressure losses across the different parts of the completionrnand the flow and pressure capacity of the gas lift system.
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