IMPROVED INFLOW PERFORMANCE RELATIONSHIPS AND IMPROVED WELL BORE PERFORMANCE

Abstract

The inflow performance relationship for oil proposed by Vogel (1968) and extended by Brown (1981) has been modified empirically to allow for variations in water cut and gas liquid ratio.

The well bore performance of wells flowing or gas lifting continuously is known to be affected adversely by the separation of fluids at the eductor (tubing or annulus) intake. Performance is affected mostly in wells with large well bore storage.

The design of the tubing intake also affects separation. A tubing intake that will reduce separation in flowing wells and increase separation in pumped wells has been designed and tested in a transparent model.

A qualitative estimate of the gas separation efficiency of this device has been made. The estimate is based on the Ros (1961) flow regime map and on observations by Beggs and Brill (1973) that liquid hold-up increases with well deviation up to 40º. Further tests are warranted.

Rod pump performance is analysed in detail. A spreadsheet allows comparison of pump capacity with well inflowperformance.

Even at very low gas/liquid ratios, gas separation at the tubing intake affects significantly both single and two stage pump performance.