HYDRAULIC JET PUMPING AT TINTABURRA OILFIELD

Abstract

The Hutton zone of the Tintaburra oilfield has an active bottom water drive which necessitates high gross fluid production rates to enable reserves to be produced within a reasonable period of time. A high volume artificial lift system capable of producing 8 000 to 10 000 barrels of fluid per day (BFPD) from 6 producing wells formed the basic design criteria, and hydraulic jet pumping was chosen as the means of artificial lift. The hydraulic jet pumping installation at Tintaburra was the first of its kind in Australia.

The basic principle of operation of a jet pump is the transfer of momentum from a power fluid to reservoir fluid. The power fluid is pumped through a nozzle and the corresponding increase in velocity results in a pressure drop at the nozzle exit. This drop in pressure provides the drawdown necessary to move reservoir fluid to the pump where it is entrained and mixed with the power fluid. The combined stream is produced to surface and handled using convential production techniques. Equipment required in the Tintaburra system consists of a power fluid settling and storage tank, surface power fluid pump, distribution manifold, wellhead control valves and the subsurface assembly, including the jet pump itself.

The application of mathematical equations describing jet pump operation was used in the initial selection of pumps for the Tintaburra wells. While this method provides insight into the operation of jet pumps, the use of equipment supplier's software proved to be more expedient in the final design stages and allowed many nozzle and throat combinations to be evaluated. Changes to well productivity brought about by the installation of down hole equipment required new pump selections for all wells. After nine months of operation, comprehensive production testing again highlighted changes to well productivity, necessitating variations in operating parameters or, in some cases, specification of new pumps.